Prenatal care has long included carrier screening for genetic diseases, such as cystic fibrosis and Tay-Sachs disease. Recently, advances in genetics technologies led to the development of multiplex panels that can be used to test for hundreds of genetic disorders simultaneously, and can be used to assess carrier status for expectant couples or those planning a pregnancy. Although such screening covers many more conditions than those recommended in traditional guidelines, the benefit of expanded carrier screening (ECS) over standard gene-by-gene testing is not clear.

In this Update, I review recent ECS research that can be helpful to those who practice reproductive endocrinology and infertility medicine, maternal–fetal medicine, and general ObGyn. This research considered some of the many complexities of ECS:

• number and type of severe autosomal recessive conditions identified by an ECS panel, or by panethnic screening for 3 common conditions (cystic fibrosis, fragile X syndrome, spinal muscular atrophy)
• whether the disorders covered by ECS panels meet recommended criteria regarding severity, prevalence, and test accuracy
• women’s thoughts and perspectives on ECS
• whether the marketing materials disseminated by commercial providers of ECS are accurate and balanced.

Genetic diseases identified by expanded carrier screening

Haque IS, Lazarin GA, Kang HP, Evans EA, Goldberg JD, Wapner RJ. Modeled fetal risk of genetic diseases identified by expanded carrier screening. JAMA. 2016;316(7):734-742.

Screening during pregnancy to determine if one or both parents are carriers of genetic disorders historically has involved testing for a limited number of conditions, such as cystic fibrosis, hemoglobinopathies, and Tay-Sachs disease. Patients usually are offered testing for 1 or 2 disorders, with test choices primarily based on patient race and ethnicity. Unfortunately, ancestry-based screening may result in inequitable distribution of genetic testing and resources, as it has significant limitations in our increasingly multicultural society, which includes many people of uncertain or mixed race and ethnicity.

Advantages of expanded carrier screening

Several commercial laboratories now offer ECS. Haque and colleagues used data from one of these laboratories and modeled the predicted number of potentially affected fetuses that would be identified with traditional, ethnicity-based screening as compared with ECS. In one of their hypothetical cohorts, of Northern European couples, traditional screening would identify 55 affected fetuses per 100,000 (1 in 1,800), and ECS would identify 159 per 100,000 (almost 3 times more). The numbers identified with ECS varied with race or ethnicity and ranged from 94 per 100,000 (about 1 in 1,000) for Hispanic couples to 392 per 100,000 (about 1 in 250) for Ashkenazi Jewish couples.

In Australia, Archibald and colleagues conducted a similar study, of panethnic screening of 12,000 women for cystic fibrosis, fragile X syndrome, and spinal muscular atrophy.¹ The number of affected fetuses identified was about 1 per 1,000 screened couples--not much different from the ECS number, though comparison is difficult given the likely very different racial and ethnic backgrounds of the 2 cohorts.

Although these data suggest ECS increases detection of genetic disorders, and it seems almost self-evident that more screening is better, there are concerns about ECS.² Traditional carrier screening methods focus on conditions that significantly affect quality of life--owing to cognitive or physical disabilities or required lifelong medical therapies--and that have a fetal, neonatal, or early-childhood onset and well-defined phenotype. In ECS panels, additional conditions may vary significantly in severity or age of onset. Although some genetic variants on ECS panels have a consistent phenotype, the natural history of others is less well understood. Panels often include conditions for which carrier screening of the general population is not recommended by current guidelines--for example, hemochromatosis and factor V Leiden. Moreover, almost by definition, ECS panels include rare conditions for which the natural history may not be well understood, and the carrier frequency as well as the proportion of condition-causing variants that can be detected may be unclear, leaving the residual risk unknown.

Read about the ideal expanded carrier screening panel.

The ideal expanded carrier screening panel

Stevens B, Krstic N, Jones M, Murphy L, Hoskovec J. Finding middle ground in constructing a clinically useful expanded carrier screening panel. Obstet Gynecol. 2017;130(2):279-284.

Both the American College of Obstetricians and Gynecologists (ACOG) and the American College of Medical Genetics and Genomics (ACMG) have proposed criteria for including specific disorders on ECS panels.^3,4 These criteria consider disorder characteristics, such as carrier prevalence, which should be at least 1 in 100; severity; early-childhood onset; and complete penetrance. In addition, they consider test characteristics, such as sensitivity, which should be at least 70%.

Details of the study

Stevens and colleagues evaluated the ECS panels offered by 6 commercial laboratories in the United States. They found that only 27% of included conditions met the recommended criteria, and concluded that these panels are putting patients at risk for undue anxiety, and that time and money are being spent on follow-up testing for rare and mild conditions for which the benefits of testing are unclear or unlikely. The potential benefits of the extra screening should be weighed against the significant resulting harms.

Across the 6 ECS panels, 96 conditions met the criteria. As some laboratories allow providers to customize their panels, members of my practice, after reviewing this thought-provoking article, agreed we should create a custom panel that includes only these 96 conditions. Unfortunately, no commercial laboratory includes all 96 conditions, so it is not feasible to create an "ideal" panel at this time.

Arguments favoring ECS include its low cost and the efficiency of screening with multigene panels. In a 2013 study, however, 24% of patients were identified as carriers, and in most cases this finding led to screening for the reproductive partner as well.⁵ If the rate of detection of the disorder is low, the utility of screening with the same panel may be limited, and couples may require more extensive testing, such as gene sequencing, which is far more expensive. These findings and the additional testing also will increase the need for genetic counseling, and may lead to invasive prenatal diagnostic testing with further increases in costs. If counseling and prenatal testing yield improved outcomes--increased detection of important findings--the benefit will justify the higher costs. However, if the increased costs are largely generated chasing down and explaining findings that are not important to patients or providers, the costs may be incurred without benefit.

Read about the pregnant women’s perspectives on ECS.

Pregnant women's perspectives on expanded carrier screening

Propst L, Connor G, Hinton M, Poorvu T, Dungan J. Pregnant women's perspectives on expanded carrier screening [published online February 23, 2018]. J Genet Couns. doi:10.1007/s10897-018-0232-x.

Although several authors have discussed ECS detection rates, less has been reported on how women perceive ECS or how they elect or decline screening. Studies have found that the decision to undergo screening for cystic fibrosis is influenced by factors that include age, sex, ethnicity, socioeconomic status, lack of family history, cost, fear of a blood test, lack of knowledge about the condition, already having children, wanting to avoid having a disabled child, abortion preferences, and feeling pressured by health care providers.^6,7 Propst and colleagues asked women for their perspectives on ECS, on electing or declining screening, and on any anxiety associated with their decision.

Details of the study

Women who declined ECS said they did so because they:

• had no family history
• knew there was a very small chance their partner carried the same condition  
• would not change the course of their pregnancy on the basis of the test results.

Women who elected ECS said they did so because they wanted to:

• know their risk of having a child with a genetic condition
• have all available information about their genetic risks
• be able to make decisions about continuing or terminating their pregnancy.

Women also were asked what they would do if they discovered their fetus had a genetic disorder. About 42% said they were unsure what they would do, 34% said they would continue their pregnancy and prepare for the birth of an affected child, and 24% said they likely would terminate their pregnancy.

The most common reason women gave for declining ECS was that they had no family history. However, ECS is not a good option for women with a positive family history, as they need genetic counseling and specific consideration of their own risks and what testing should be done. The majority of couples who have a child with a genetic disease have no other family history of the disorder. In a study of reproductive carrier screening in Australia, 88% of carriers had no family history.¹ Careful pretest counseling is needed to explain the distinction between, on one hand, genetic counseling and testing for those with a family history of genetic disease and, on the other hand, population screening performed to identify unsuspecting individuals who are healthy carriers of genetic disorders.

Another crucial point about carrier screening is the need to consider how its results will be used, and what options the carrier couple will have. For women who are pregnant when a risk is identified, options include expectant management, with diagnosis after birth, or prenatal diagnosis with termination of an affected fetus, out-adoption of an affected fetus, or expectant management with preparation for caring for an affected child. For women who are not pregnant when they have ECS, additional options include use of a gamete (ovum or sperm) donor to achieve pregnancy, or preimplantation genetic diagnosis with implantation of only unaffected embryos.

Read about the marketing of ECS.

Marketing of expanded carrier screening

Chokoshvili D, Borry P, Vears DF. A systematic analysis of online marketing materials used by providers of expanded carrier screening [published online December 14, 2017]. Genet Med. doi:10.1038/gim.2017.222.

Prenatal carrier screening can be helpful to women and their families, but it is also a high-volume, lucrative business, with many commercial laboratories competing for the growing ECS market. Professional medical societies recommend making all screening candidates aware of the purpose, characteristics, and limitations of the tests, and of the potential significance of their results. As becoming familiar and comfortable with the tests and explaining them to each patient can be time-consuming, and daunting, many busy clinicians have started relying on marketing materials and other information from the commercial laboratories. Therefore analysis of the accuracy of such materials is in order.

Details of the study

Chokoshvili and colleagues performed a systematic analysis of the quality and accuracy of online marketing materials for ECS. They identified 18 providers: 16 commercial laboratories and 2 medical services providers. All described ECS as a useful tool for family planning, and some were very directive in stating that this testing is "one of the most important steps in preparing for parenthood." In their materials, most of the companies cover some limitations, such as residual risk, but none of the commercial laboratories indicate that ECS can overestimate risk (many variants have incomplete penetrance, meaning that some individuals with a positive test result may in fact be asymptomatic throughout their lifetime).

In addition, whereas a large amount of the marketing materials implies the test was developed in line with professional recommendations, none in fact complies with ACOG and ACMG guidance. Finally, though some of the online information provided by laboratories can be helpful, it is important for clinicians to remember that reproductive genetic counseling should be nondirective and balanced. Carrier testing should be based on patient (not provider) values regarding reproductive autonomy.

Summary

ECS increasingly is being adopted into clinical practice. According to ACOG, traditional ethnicity-based screening, panethnic screening (the same limited panel of tests for all patients), and ECS are all acceptable alternatives for prenatal carrier screening.³ For providers who offer ECS, it is important to have a good understanding of each selected test and its limitations. Providers should have a plan for following up patients who have positive test results; this plan may include having genetic counseling and prenatal genetic diagnostic testing in place. Although treatment is available for a few genetic conditions, for the large majority, prenatal screening has not been proved to lead to improved therapeutic options. Providers should try to make sure that patients do not have unrealistic expectations of the outcomes of carrier screening.

Share your thoughts! Send your Letter to the Editor to [email protected]. Please include your name and the city and state in which you practice.

Prenatal care has long included carrier screening for genetic diseases, such as cystic fibrosis and Tay-Sachs disease. Recently, advances in genetics technologies led to the development of multiplex panels that can be used to test for hundreds of genetic disorders simultaneously, and can be used to assess carrier status for expectant couples or those planning a pregnancy. Although such screening covers many more conditions than those recommended in traditional guidelines, the benefit of expanded carrier screening (ECS) over standard gene-by-gene testing is not clear.

In this Update, I review recent ECS research that can be helpful to those who practice reproductive endocrinology and infertility medicine, maternal–fetal medicine, and general ObGyn. This research considered some of the many complexities of ECS:

• number and type of severe autosomal recessive conditions identified by an ECS panel, or by panethnic screening for 3 common conditions (cystic fibrosis, fragile X syndrome, spinal muscular atrophy)
• whether the disorders covered by ECS panels meet recommended criteria regarding severity, prevalence, and test accuracy
• women’s thoughts and perspectives on ECS
• whether the marketing materials disseminated by commercial providers of ECS are accurate and balanced.

Genetic diseases identified by expanded carrier screening

Haque IS, Lazarin GA, Kang HP, Evans EA, Goldberg JD, Wapner RJ. Modeled fetal risk of genetic diseases identified by expanded carrier screening. JAMA. 2016;316(7):734-742.

Screening during pregnancy to determine if one or both parents are carriers of genetic disorders historically has involved testing for a limited number of conditions, such as cystic fibrosis, hemoglobinopathies, and Tay-Sachs disease. Patients usually are offered testing for 1 or 2 disorders, with test choices primarily based on patient race and ethnicity. Unfortunately, ancestry-based screening may result in inequitable distribution of genetic testing and resources, as it has significant limitations in our increasingly multicultural society, which includes many people of uncertain or mixed race and ethnicity.

Advantages of expanded carrier screening

Several commercial laboratories now offer ECS. Haque and colleagues used data from one of these laboratories and modeled the predicted number of potentially affected fetuses that would be identified with traditional, ethnicity-based screening as compared with ECS. In one of their hypothetical cohorts, of Northern European couples, traditional screening would identify 55 affected fetuses per 100,000 (1 in 1,800), and ECS would identify 159 per 100,000 (almost 3 times more). The numbers identified with ECS varied with race or ethnicity and ranged from 94 per 100,000 (about 1 in 1,000) for Hispanic couples to 392 per 100,000 (about 1 in 250) for Ashkenazi Jewish couples.

In Australia, Archibald and colleagues conducted a similar study, of panethnic screening of 12,000 women for cystic fibrosis, fragile X syndrome, and spinal muscular atrophy.¹ The number of affected fetuses identified was about 1 per 1,000 screened couples--not much different from the ECS number, though comparison is difficult given the likely very different racial and ethnic backgrounds of the 2 cohorts.

Although these data suggest ECS increases detection of genetic disorders, and it seems almost self-evident that more screening is better, there are concerns about ECS.² Traditional carrier screening methods focus on conditions that significantly affect quality of life--owing to cognitive or physical disabilities or required lifelong medical therapies--and that have a fetal, neonatal, or early-childhood onset and well-defined phenotype. In ECS panels, additional conditions may vary significantly in severity or age of onset. Although some genetic variants on ECS panels have a consistent phenotype, the natural history of others is less well understood. Panels often include conditions for which carrier screening of the general population is not recommended by current guidelines--for example, hemochromatosis and factor V Leiden. Moreover, almost by definition, ECS panels include rare conditions for which the natural history may not be well understood, and the carrier frequency as well as the proportion of condition-causing variants that can be detected may be unclear, leaving the residual risk unknown.

Read about the ideal expanded carrier screening panel.

The ideal expanded carrier screening panel

Stevens B, Krstic N, Jones M, Murphy L, Hoskovec J. Finding middle ground in constructing a clinically useful expanded carrier screening panel. Obstet Gynecol. 2017;130(2):279-284.

Both the American College of Obstetricians and Gynecologists (ACOG) and the American College of Medical Genetics and Genomics (ACMG) have proposed criteria for including specific disorders on ECS panels.^3,4 These criteria consider disorder characteristics, such as carrier prevalence, which should be at least 1 in 100; severity; early-childhood onset; and complete penetrance. In addition, they consider test characteristics, such as sensitivity, which should be at least 70%.

Details of the study

Stevens and colleagues evaluated the ECS panels offered by 6 commercial laboratories in the United States. They found that only 27% of included conditions met the recommended criteria, and concluded that these panels are putting patients at risk for undue anxiety, and that time and money are being spent on follow-up testing for rare and mild conditions for which the benefits of testing are unclear or unlikely. The potential benefits of the extra screening should be weighed against the significant resulting harms.

Across the 6 ECS panels, 96 conditions met the criteria. As some laboratories allow providers to customize their panels, members of my practice, after reviewing this thought-provoking article, agreed we should create a custom panel that includes only these 96 conditions. Unfortunately, no commercial laboratory includes all 96 conditions, so it is not feasible to create an "ideal" panel at this time.

Arguments favoring ECS include its low cost and the efficiency of screening with multigene panels. In a 2013 study, however, 24% of patients were identified as carriers, and in most cases this finding led to screening for the reproductive partner as well.⁵ If the rate of detection of the disorder is low, the utility of screening with the same panel may be limited, and couples may require more extensive testing, such as gene sequencing, which is far more expensive. These findings and the additional testing also will increase the need for genetic counseling, and may lead to invasive prenatal diagnostic testing with further increases in costs. If counseling and prenatal testing yield improved outcomes--increased detection of important findings--the benefit will justify the higher costs. However, if the increased costs are largely generated chasing down and explaining findings that are not important to patients or providers, the costs may be incurred without benefit.

Read about the pregnant women’s perspectives on ECS.

Pregnant women's perspectives on expanded carrier screening

Propst L, Connor G, Hinton M, Poorvu T, Dungan J. Pregnant women's perspectives on expanded carrier screening [published online February 23, 2018]. J Genet Couns. doi:10.1007/s10897-018-0232-x.

Although several authors have discussed ECS detection rates, less has been reported on how women perceive ECS or how they elect or decline screening. Studies have found that the decision to undergo screening for cystic fibrosis is influenced by factors that include age, sex, ethnicity, socioeconomic status, lack of family history, cost, fear of a blood test, lack of knowledge about the condition, already having children, wanting to avoid having a disabled child, abortion preferences, and feeling pressured by health care providers.^6,7 Propst and colleagues asked women for their perspectives on ECS, on electing or declining screening, and on any anxiety associated with their decision.

Details of the study

Women who declined ECS said they did so because they:

• had no family history
• knew there was a very small chance their partner carried the same condition  
• would not change the course of their pregnancy on the basis of the test results.

Women who elected ECS said they did so because they wanted to:

• know their risk of having a child with a genetic condition
• have all available information about their genetic risks
• be able to make decisions about continuing or terminating their pregnancy.

Women also were asked what they would do if they discovered their fetus had a genetic disorder. About 42% said they were unsure what they would do, 34% said they would continue their pregnancy and prepare for the birth of an affected child, and 24% said they likely would terminate their pregnancy.

The most common reason women gave for declining ECS was that they had no family history. However, ECS is not a good option for women with a positive family history, as they need genetic counseling and specific consideration of their own risks and what testing should be done. The majority of couples who have a child with a genetic disease have no other family history of the disorder. In a study of reproductive carrier screening in Australia, 88% of carriers had no family history.¹ Careful pretest counseling is needed to explain the distinction between, on one hand, genetic counseling and testing for those with a family history of genetic disease and, on the other hand, population screening performed to identify unsuspecting individuals who are healthy carriers of genetic disorders.

Another crucial point about carrier screening is the need to consider how its results will be used, and what options the carrier couple will have. For women who are pregnant when a risk is identified, options include expectant management, with diagnosis after birth, or prenatal diagnosis with termination of an affected fetus, out-adoption of an affected fetus, or expectant management with preparation for caring for an affected child. For women who are not pregnant when they have ECS, additional options include use of a gamete (ovum or sperm) donor to achieve pregnancy, or preimplantation genetic diagnosis with implantation of only unaffected embryos.

Read about the marketing of ECS.

Marketing of expanded carrier screening

Chokoshvili D, Borry P, Vears DF. A systematic analysis of online marketing materials used by providers of expanded carrier screening [published online December 14, 2017]. Genet Med. doi:10.1038/gim.2017.222.

Prenatal carrier screening can be helpful to women and their families, but it is also a high-volume, lucrative business, with many commercial laboratories competing for the growing ECS market. Professional medical societies recommend making all screening candidates aware of the purpose, characteristics, and limitations of the tests, and of the potential significance of their results. As becoming familiar and comfortable with the tests and explaining them to each patient can be time-consuming, and daunting, many busy clinicians have started relying on marketing materials and other information from the commercial laboratories. Therefore analysis of the accuracy of such materials is in order.

Details of the study

Chokoshvili and colleagues performed a systematic analysis of the quality and accuracy of online marketing materials for ECS. They identified 18 providers: 16 commercial laboratories and 2 medical services providers. All described ECS as a useful tool for family planning, and some were very directive in stating that this testing is "one of the most important steps in preparing for parenthood." In their materials, most of the companies cover some limitations, such as residual risk, but none of the commercial laboratories indicate that ECS can overestimate risk (many variants have incomplete penetrance, meaning that some individuals with a positive test result may in fact be asymptomatic throughout their lifetime).

In addition, whereas a large amount of the marketing materials implies the test was developed in line with professional recommendations, none in fact complies with ACOG and ACMG guidance. Finally, though some of the online information provided by laboratories can be helpful, it is important for clinicians to remember that reproductive genetic counseling should be nondirective and balanced. Carrier testing should be based on patient (not provider) values regarding reproductive autonomy.

Summary

ECS increasingly is being adopted into clinical practice. According to ACOG, traditional ethnicity-based screening, panethnic screening (the same limited panel of tests for all patients), and ECS are all acceptable alternatives for prenatal carrier screening.³ For providers who offer ECS, it is important to have a good understanding of each selected test and its limitations. Providers should have a plan for following up patients who have positive test results; this plan may include having genetic counseling and prenatal genetic diagnostic testing in place. Although treatment is available for a few genetic conditions, for the large majority, prenatal screening has not been proved to lead to improved therapeutic options. Providers should try to make sure that patients do not have unrealistic expectations of the outcomes of carrier screening.

Share your thoughts! Send your Letter to the Editor to [email protected]. Please include your name and the city and state in which you practice.

Prenatal care has long included carrier screening for genetic diseases, such as cystic fibrosis and Tay-Sachs disease. Recently, advances in genetics technologies led to the development of multiplex panels that can be used to test for hundreds of genetic disorders simultaneously, and can be used to assess carrier status for expectant couples or those planning a pregnancy. Although such screening covers many more conditions than those recommended in traditional guidelines, the benefit of expanded carrier screening (ECS) over standard gene-by-gene testing is not clear.

In this Update, I review recent ECS research that can be helpful to those who practice reproductive endocrinology and infertility medicine, maternal–fetal medicine, and general ObGyn. This research considered some of the many complexities of ECS:

• number and type of severe autosomal recessive conditions identified by an ECS panel, or by panethnic screening for 3 common conditions (cystic fibrosis, fragile X syndrome, spinal muscular atrophy)
• whether the disorders covered by ECS panels meet recommended criteria regarding severity, prevalence, and test accuracy
• women’s thoughts and perspectives on ECS
• whether the marketing materials disseminated by commercial providers of ECS are accurate and balanced.

Genetic diseases identified by expanded carrier screening

Haque IS, Lazarin GA, Kang HP, Evans EA, Goldberg JD, Wapner RJ. Modeled fetal risk of genetic diseases identified by expanded carrier screening. JAMA. 2016;316(7):734-742.

Screening during pregnancy to determine if one or both parents are carriers of genetic disorders historically has involved testing for a limited number of conditions, such as cystic fibrosis, hemoglobinopathies, and Tay-Sachs disease. Patients usually are offered testing for 1 or 2 disorders, with test choices primarily based on patient race and ethnicity. Unfortunately, ancestry-based screening may result in inequitable distribution of genetic testing and resources, as it has significant limitations in our increasingly multicultural society, which includes many people of uncertain or mixed race and ethnicity.

Advantages of expanded carrier screening

Several commercial laboratories now offer ECS. Haque and colleagues used data from one of these laboratories and modeled the predicted number of potentially affected fetuses that would be identified with traditional, ethnicity-based screening as compared with ECS. In one of their hypothetical cohorts, of Northern European couples, traditional screening would identify 55 affected fetuses per 100,000 (1 in 1,800), and ECS would identify 159 per 100,000 (almost 3 times more). The numbers identified with ECS varied with race or ethnicity and ranged from 94 per 100,000 (about 1 in 1,000) for Hispanic couples to 392 per 100,000 (about 1 in 250) for Ashkenazi Jewish couples.

In Australia, Archibald and colleagues conducted a similar study, of panethnic screening of 12,000 women for cystic fibrosis, fragile X syndrome, and spinal muscular atrophy.¹ The number of affected fetuses identified was about 1 per 1,000 screened couples--not much different from the ECS number, though comparison is difficult given the likely very different racial and ethnic backgrounds of the 2 cohorts.

Although these data suggest ECS increases detection of genetic disorders, and it seems almost self-evident that more screening is better, there are concerns about ECS.² Traditional carrier screening methods focus on conditions that significantly affect quality of life--owing to cognitive or physical disabilities or required lifelong medical therapies--and that have a fetal, neonatal, or early-childhood onset and well-defined phenotype. In ECS panels, additional conditions may vary significantly in severity or age of onset. Although some genetic variants on ECS panels have a consistent phenotype, the natural history of others is less well understood. Panels often include conditions for which carrier screening of the general population is not recommended by current guidelines--for example, hemochromatosis and factor V Leiden. Moreover, almost by definition, ECS panels include rare conditions for which the natural history may not be well understood, and the carrier frequency as well as the proportion of condition-causing variants that can be detected may be unclear, leaving the residual risk unknown.

Read about the ideal expanded carrier screening panel.

The ideal expanded carrier screening panel

Stevens B, Krstic N, Jones M, Murphy L, Hoskovec J. Finding middle ground in constructing a clinically useful expanded carrier screening panel. Obstet Gynecol. 2017;130(2):279-284.

Both the American College of Obstetricians and Gynecologists (ACOG) and the American College of Medical Genetics and Genomics (ACMG) have proposed criteria for including specific disorders on ECS panels.^3,4 These criteria consider disorder characteristics, such as carrier prevalence, which should be at least 1 in 100; severity; early-childhood onset; and complete penetrance. In addition, they consider test characteristics, such as sensitivity, which should be at least 70%.

Details of the study

Stevens and colleagues evaluated the ECS panels offered by 6 commercial laboratories in the United States. They found that only 27% of included conditions met the recommended criteria, and concluded that these panels are putting patients at risk for undue anxiety, and that time and money are being spent on follow-up testing for rare and mild conditions for which the benefits of testing are unclear or unlikely. The potential benefits of the extra screening should be weighed against the significant resulting harms.

Across the 6 ECS panels, 96 conditions met the criteria. As some laboratories allow providers to customize their panels, members of my practice, after reviewing this thought-provoking article, agreed we should create a custom panel that includes only these 96 conditions. Unfortunately, no commercial laboratory includes all 96 conditions, so it is not feasible to create an "ideal" panel at this time.

Arguments favoring ECS include its low cost and the efficiency of screening with multigene panels. In a 2013 study, however, 24% of patients were identified as carriers, and in most cases this finding led to screening for the reproductive partner as well.⁵ If the rate of detection of the disorder is low, the utility of screening with the same panel may be limited, and couples may require more extensive testing, such as gene sequencing, which is far more expensive. These findings and the additional testing also will increase the need for genetic counseling, and may lead to invasive prenatal diagnostic testing with further increases in costs. If counseling and prenatal testing yield improved outcomes--increased detection of important findings--the benefit will justify the higher costs. However, if the increased costs are largely generated chasing down and explaining findings that are not important to patients or providers, the costs may be incurred without benefit.

Read about the pregnant women’s perspectives on ECS.

Pregnant women's perspectives on expanded carrier screening

Propst L, Connor G, Hinton M, Poorvu T, Dungan J. Pregnant women's perspectives on expanded carrier screening [published online February 23, 2018]. J Genet Couns. doi:10.1007/s10897-018-0232-x.

Although several authors have discussed ECS detection rates, less has been reported on how women perceive ECS or how they elect or decline screening. Studies have found that the decision to undergo screening for cystic fibrosis is influenced by factors that include age, sex, ethnicity, socioeconomic status, lack of family history, cost, fear of a blood test, lack of knowledge about the condition, already having children, wanting to avoid having a disabled child, abortion preferences, and feeling pressured by health care providers.^6,7 Propst and colleagues asked women for their perspectives on ECS, on electing or declining screening, and on any anxiety associated with their decision.

Details of the study

Women who declined ECS said they did so because they:

• had no family history
• knew there was a very small chance their partner carried the same condition  
• would not change the course of their pregnancy on the basis of the test results.

Women who elected ECS said they did so because they wanted to:

• know their risk of having a child with a genetic condition
• have all available information about their genetic risks
• be able to make decisions about continuing or terminating their pregnancy.

Women also were asked what they would do if they discovered their fetus had a genetic disorder. About 42% said they were unsure what they would do, 34% said they would continue their pregnancy and prepare for the birth of an affected child, and 24% said they likely would terminate their pregnancy.

The most common reason women gave for declining ECS was that they had no family history. However, ECS is not a good option for women with a positive family history, as they need genetic counseling and specific consideration of their own risks and what testing should be done. The majority of couples who have a child with a genetic disease have no other family history of the disorder. In a study of reproductive carrier screening in Australia, 88% of carriers had no family history.¹ Careful pretest counseling is needed to explain the distinction between, on one hand, genetic counseling and testing for those with a family history of genetic disease and, on the other hand, population screening performed to identify unsuspecting individuals who are healthy carriers of genetic disorders.

Another crucial point about carrier screening is the need to consider how its results will be used, and what options the carrier couple will have. For women who are pregnant when a risk is identified, options include expectant management, with diagnosis after birth, or prenatal diagnosis with termination of an affected fetus, out-adoption of an affected fetus, or expectant management with preparation for caring for an affected child. For women who are not pregnant when they have ECS, additional options include use of a gamete (ovum or sperm) donor to achieve pregnancy, or preimplantation genetic diagnosis with implantation of only unaffected embryos.

Read about the marketing of ECS.

Marketing of expanded carrier screening

Chokoshvili D, Borry P, Vears DF. A systematic analysis of online marketing materials used by providers of expanded carrier screening [published online December 14, 2017]. Genet Med. doi:10.1038/gim.2017.222.

Prenatal carrier screening can be helpful to women and their families, but it is also a high-volume, lucrative business, with many commercial laboratories competing for the growing ECS market. Professional medical societies recommend making all screening candidates aware of the purpose, characteristics, and limitations of the tests, and of the potential significance of their results. As becoming familiar and comfortable with the tests and explaining them to each patient can be time-consuming, and daunting, many busy clinicians have started relying on marketing materials and other information from the commercial laboratories. Therefore analysis of the accuracy of such materials is in order.

Details of the study

Chokoshvili and colleagues performed a systematic analysis of the quality and accuracy of online marketing materials for ECS. They identified 18 providers: 16 commercial laboratories and 2 medical services providers. All described ECS as a useful tool for family planning, and some were very directive in stating that this testing is "one of the most important steps in preparing for parenthood." In their materials, most of the companies cover some limitations, such as residual risk, but none of the commercial laboratories indicate that ECS can overestimate risk (many variants have incomplete penetrance, meaning that some individuals with a positive test result may in fact be asymptomatic throughout their lifetime).

In addition, whereas a large amount of the marketing materials implies the test was developed in line with professional recommendations, none in fact complies with ACOG and ACMG guidance. Finally, though some of the online information provided by laboratories can be helpful, it is important for clinicians to remember that reproductive genetic counseling should be nondirective and balanced. Carrier testing should be based on patient (not provider) values regarding reproductive autonomy.

Summary

ECS increasingly is being adopted into clinical practice. According to ACOG, traditional ethnicity-based screening, panethnic screening (the same limited panel of tests for all patients), and ECS are all acceptable alternatives for prenatal carrier screening.³ For providers who offer ECS, it is important to have a good understanding of each selected test and its limitations. Providers should have a plan for following up patients who have positive test results; this plan may include having genetic counseling and prenatal genetic diagnostic testing in place. Although treatment is available for a few genetic conditions, for the large majority, prenatal screening has not been proved to lead to improved therapeutic options. Providers should try to make sure that patients do not have unrealistic expectations of the outcomes of carrier screening.

Share your thoughts! Send your Letter to the Editor to [email protected]. Please include your name and the city and state in which you practice.

The Third Annual "UCLA / SVS Symposium: A Comprehensive Review and Update of What's New in Vascular and Endovascular Surgery," is set for Aug. 25 to 27 in California. This course is offered by the Division of Vascular and Endovascular Surgery at UCLA and the Society for Vascular Surgery. It provides an in-depth review of our specialty for those preparing to take the vascular board examinations as well as providing the basic didactic education for vascular residents and fellows in training.

The Third Annual "UCLA / SVS Symposium: A Comprehensive Review and Update of What's New in Vascular and Endovascular Surgery," is set for Aug. 25 to 27 in California. This course is offered by the Division of Vascular and Endovascular Surgery at UCLA and the Society for Vascular Surgery. It provides an in-depth review of our specialty for those preparing to take the vascular board examinations as well as providing the basic didactic education for vascular residents and fellows in training.

The Third Annual "UCLA / SVS Symposium: A Comprehensive Review and Update of What's New in Vascular and Endovascular Surgery," is set for Aug. 25 to 27 in California. This course is offered by the Division of Vascular and Endovascular Surgery at UCLA and the Society for Vascular Surgery. It provides an in-depth review of our specialty for those preparing to take the vascular board examinations as well as providing the basic didactic education for vascular residents and fellows in training.

Want to make a billion dollars? Here’s a hot tip: Invent wearable technology that detects diabetes, measures glucose levels, and determines how much insulin is needed – all without the need for a single drop of blood.

If you accept this mission, there’s a catch: You’ll have a whole bunch of company. When it comes to using technology to free patients with diabetes from the dreaded finger stick, “hope springs eternal in the hearts of scientists, entrepreneurs, opportunists, and charlatans alike,” writes electrochemical specialist and consultant John L. Smith, PhD, in his book “The Pursuit of Noninvasive Glucose.”

Google and Apple have been in the hunt, along with countless makers of devices and software. A noninvasive glucose monitoring system is the prime target, but there’s also plenty of interest in software that puts data from such devices as heartbeat sensors to work.

Early failure has a lasting impact

In the beginning, there was Glucowatch. And it was not good.

The GlucoWatch G2 Biographer product received approval from the Food and Drug Administration back in 2001 and touted as a high-tech tool to monitor glucose levels via interstitial concentrations every 10 minutes. The device promised to draw glucose to the skin surface for measurement via electric shocks, and alarms were to go off when hypoglycemia or hyperglycemia was detected.

But numerous problems cropped up. There was a time lag, with the device estimating glucose levels that actually occurred 15-20 minutes earlier. Some patients couldn’t tolerate wearing the watch, and some were burned by the electric current.

And perhaps worst of all, the measurements often weren’t accurate, with one study finding that more than half of 240 nighttime alarms incorrectly warned children with diabetes of dangerously high or low glucose. (Diabetes Technol Ther. 2005 June; 7[3]:440-7).

As a result of the Glucowatch debacle, the FDA “become a little gun shy about approving anything. It made it even harder to approve something,” said Mark J. Rice, MD, of Vanderbilt University, Nashville, Tenn., who has tried to develop glucose-measuring technology.

On tech front, promises and more promises

So far, there have been more promises than actual products.

If you don’t look too closely at the website of a device called GlucoWise, you might assume a noninvasive glucose monitor already exists. Under a photo of a smiling woman, the site promises a “100% pain-free device that makes traditional blood sampling a thing of the past.”

The “simple yet highly reliable” device, which looks a bit like a large clip for a potato chip bag, promises to measure glucose through high-frequency radio waves that penetrate thin body tissue in the earlobe or the area between the thumb and forefinger.

But the GlucoWise device is neither approved nor available, and the company’s predictions that it would take preorders by late 2016 didn’t come true.

Another product called SugarBEAT missed its planned 2016 release and now hopes to be available in the Britain later this year. It promises to measure glucose levels every 5 minutes via a small disposable patch that draws interstitial fluid from the skin.

Meanwhile, Apple has enlisted biomedical engineers to work on a secret project to measure glucose continuously and noninvasively, CNBC reported last year. And Google announced in 2014 that it was working on a glucose-detecting contact lens that could alert patients via tiny LED lights – yes, apparently in the lenses themselves – if levels go too high or low. But neither of these technologies is ready for prime time.

Sneaky glucose molecules elude scientists

According to Dr. Rice, no truly noninvasive glucose-measuring technique has worked so far.

The challenge, he said, is that it’s difficult to measure tiny glucose molecules, which have no color and share many characteristics with H₂O.

“The real problem is trying to measure a colorless molecule in a sea of water,” Dr. Rice said.

Glucose lab tests rely on indicators from reactions with other substances, he said, “but you can’t do that in the body.” Measuring glucose in tears or urine is one possibility, he said, but the scarcity in those liquids poses a challenge: “Your body doesn’t want to spill glucose and lose energy.”

Dr. Rice himself explored a glucose-measuring technique that aimed to correlate glucose levels to the speed of the retina’s reaction to light. The idea was that patients would wear special glasses that would shine a light in the eye at the press of a button. The project ultimately failed.

There are other challenges, said Dr. Baers, the technology adviser. “Glucose concentrations in sweat or tears are not reflective of blood glucose concentrations. To make things even more challenging, glucose levels in these fluids are orders of magnitude smaller than that found in blood.”

And, she said, there’s a time lag between glucose levels in blood and in other body fluids. “This means that a sweat glucose level is really giving information from an hour previous, which can be dangerous if you’re operating machinery or driving.”

Wearable diabetes tech targets more than glucose

There’s more to wearable, noninvasive diabetes technology than glucose-monitoring. One of the new frontiers is diagnostics.

Earlier this year, researchers from the University of California at San Francisco and the digital startup Cardiogram reported that they were able to use data from digital heart rate sensors (like those found in Apple Watches, Fitbits and other devices) to correctly detect diabetes in patients.

In a study presented at the 2018 meeting of the Association for the Advancement of Artificial Intelligence, the researchers said they detected diabetes in 85% of 462 participants (out of a pool of 14,011) who’d previously been diagnosed with the condition (AAAAI abstract arXiv:1802.02511v1 [cs.LG]).

As tech advances, questions remain

San Diego’s Scripps Whittier Diabetes Institute is another player in the diabetes/digital health world. It’s currently working on several clinical trials of diabetes technology, including a study into whether older adults with type 1 diabetes will benefit from a continuous glucose monitoring device with a wireless connection.

[email protected]

Want to make a billion dollars? Here’s a hot tip: Invent wearable technology that detects diabetes, measures glucose levels, and determines how much insulin is needed – all without the need for a single drop of blood.

If you accept this mission, there’s a catch: You’ll have a whole bunch of company. When it comes to using technology to free patients with diabetes from the dreaded finger stick, “hope springs eternal in the hearts of scientists, entrepreneurs, opportunists, and charlatans alike,” writes electrochemical specialist and consultant John L. Smith, PhD, in his book “The Pursuit of Noninvasive Glucose.”

Google and Apple have been in the hunt, along with countless makers of devices and software. A noninvasive glucose monitoring system is the prime target, but there’s also plenty of interest in software that puts data from such devices as heartbeat sensors to work.

Early failure has a lasting impact

In the beginning, there was Glucowatch. And it was not good.

The GlucoWatch G2 Biographer product received approval from the Food and Drug Administration back in 2001 and touted as a high-tech tool to monitor glucose levels via interstitial concentrations every 10 minutes. The device promised to draw glucose to the skin surface for measurement via electric shocks, and alarms were to go off when hypoglycemia or hyperglycemia was detected.

But numerous problems cropped up. There was a time lag, with the device estimating glucose levels that actually occurred 15-20 minutes earlier. Some patients couldn’t tolerate wearing the watch, and some were burned by the electric current.

And perhaps worst of all, the measurements often weren’t accurate, with one study finding that more than half of 240 nighttime alarms incorrectly warned children with diabetes of dangerously high or low glucose. (Diabetes Technol Ther. 2005 June; 7[3]:440-7).

As a result of the Glucowatch debacle, the FDA “become a little gun shy about approving anything. It made it even harder to approve something,” said Mark J. Rice, MD, of Vanderbilt University, Nashville, Tenn., who has tried to develop glucose-measuring technology.

On tech front, promises and more promises

So far, there have been more promises than actual products.

If you don’t look too closely at the website of a device called GlucoWise, you might assume a noninvasive glucose monitor already exists. Under a photo of a smiling woman, the site promises a “100% pain-free device that makes traditional blood sampling a thing of the past.”

The “simple yet highly reliable” device, which looks a bit like a large clip for a potato chip bag, promises to measure glucose through high-frequency radio waves that penetrate thin body tissue in the earlobe or the area between the thumb and forefinger.

But the GlucoWise device is neither approved nor available, and the company’s predictions that it would take preorders by late 2016 didn’t come true.

Another product called SugarBEAT missed its planned 2016 release and now hopes to be available in the Britain later this year. It promises to measure glucose levels every 5 minutes via a small disposable patch that draws interstitial fluid from the skin.

Meanwhile, Apple has enlisted biomedical engineers to work on a secret project to measure glucose continuously and noninvasively, CNBC reported last year. And Google announced in 2014 that it was working on a glucose-detecting contact lens that could alert patients via tiny LED lights – yes, apparently in the lenses themselves – if levels go too high or low. But neither of these technologies is ready for prime time.

Sneaky glucose molecules elude scientists

According to Dr. Rice, no truly noninvasive glucose-measuring technique has worked so far.

The challenge, he said, is that it’s difficult to measure tiny glucose molecules, which have no color and share many characteristics with H₂O.

“The real problem is trying to measure a colorless molecule in a sea of water,” Dr. Rice said.

Glucose lab tests rely on indicators from reactions with other substances, he said, “but you can’t do that in the body.” Measuring glucose in tears or urine is one possibility, he said, but the scarcity in those liquids poses a challenge: “Your body doesn’t want to spill glucose and lose energy.”

Dr. Rice himself explored a glucose-measuring technique that aimed to correlate glucose levels to the speed of the retina’s reaction to light. The idea was that patients would wear special glasses that would shine a light in the eye at the press of a button. The project ultimately failed.

There are other challenges, said Dr. Baers, the technology adviser. “Glucose concentrations in sweat or tears are not reflective of blood glucose concentrations. To make things even more challenging, glucose levels in these fluids are orders of magnitude smaller than that found in blood.”

And, she said, there’s a time lag between glucose levels in blood and in other body fluids. “This means that a sweat glucose level is really giving information from an hour previous, which can be dangerous if you’re operating machinery or driving.”

Wearable diabetes tech targets more than glucose

There’s more to wearable, noninvasive diabetes technology than glucose-monitoring. One of the new frontiers is diagnostics.

Earlier this year, researchers from the University of California at San Francisco and the digital startup Cardiogram reported that they were able to use data from digital heart rate sensors (like those found in Apple Watches, Fitbits and other devices) to correctly detect diabetes in patients.

In a study presented at the 2018 meeting of the Association for the Advancement of Artificial Intelligence, the researchers said they detected diabetes in 85% of 462 participants (out of a pool of 14,011) who’d previously been diagnosed with the condition (AAAAI abstract arXiv:1802.02511v1 [cs.LG]).

As tech advances, questions remain

San Diego’s Scripps Whittier Diabetes Institute is another player in the diabetes/digital health world. It’s currently working on several clinical trials of diabetes technology, including a study into whether older adults with type 1 diabetes will benefit from a continuous glucose monitoring device with a wireless connection.

[email protected]

Want to make a billion dollars? Here’s a hot tip: Invent wearable technology that detects diabetes, measures glucose levels, and determines how much insulin is needed – all without the need for a single drop of blood.

If you accept this mission, there’s a catch: You’ll have a whole bunch of company. When it comes to using technology to free patients with diabetes from the dreaded finger stick, “hope springs eternal in the hearts of scientists, entrepreneurs, opportunists, and charlatans alike,” writes electrochemical specialist and consultant John L. Smith, PhD, in his book “The Pursuit of Noninvasive Glucose.”

Google and Apple have been in the hunt, along with countless makers of devices and software. A noninvasive glucose monitoring system is the prime target, but there’s also plenty of interest in software that puts data from such devices as heartbeat sensors to work.

Early failure has a lasting impact

In the beginning, there was Glucowatch. And it was not good.

The GlucoWatch G2 Biographer product received approval from the Food and Drug Administration back in 2001 and touted as a high-tech tool to monitor glucose levels via interstitial concentrations every 10 minutes. The device promised to draw glucose to the skin surface for measurement via electric shocks, and alarms were to go off when hypoglycemia or hyperglycemia was detected.

But numerous problems cropped up. There was a time lag, with the device estimating glucose levels that actually occurred 15-20 minutes earlier. Some patients couldn’t tolerate wearing the watch, and some were burned by the electric current.

And perhaps worst of all, the measurements often weren’t accurate, with one study finding that more than half of 240 nighttime alarms incorrectly warned children with diabetes of dangerously high or low glucose. (Diabetes Technol Ther. 2005 June; 7[3]:440-7).

As a result of the Glucowatch debacle, the FDA “become a little gun shy about approving anything. It made it even harder to approve something,” said Mark J. Rice, MD, of Vanderbilt University, Nashville, Tenn., who has tried to develop glucose-measuring technology.

On tech front, promises and more promises

So far, there have been more promises than actual products.

If you don’t look too closely at the website of a device called GlucoWise, you might assume a noninvasive glucose monitor already exists. Under a photo of a smiling woman, the site promises a “100% pain-free device that makes traditional blood sampling a thing of the past.”

The “simple yet highly reliable” device, which looks a bit like a large clip for a potato chip bag, promises to measure glucose through high-frequency radio waves that penetrate thin body tissue in the earlobe or the area between the thumb and forefinger.

But the GlucoWise device is neither approved nor available, and the company’s predictions that it would take preorders by late 2016 didn’t come true.

Another product called SugarBEAT missed its planned 2016 release and now hopes to be available in the Britain later this year. It promises to measure glucose levels every 5 minutes via a small disposable patch that draws interstitial fluid from the skin.

Meanwhile, Apple has enlisted biomedical engineers to work on a secret project to measure glucose continuously and noninvasively, CNBC reported last year. And Google announced in 2014 that it was working on a glucose-detecting contact lens that could alert patients via tiny LED lights – yes, apparently in the lenses themselves – if levels go too high or low. But neither of these technologies is ready for prime time.

Sneaky glucose molecules elude scientists

According to Dr. Rice, no truly noninvasive glucose-measuring technique has worked so far.

The challenge, he said, is that it’s difficult to measure tiny glucose molecules, which have no color and share many characteristics with H₂O.

“The real problem is trying to measure a colorless molecule in a sea of water,” Dr. Rice said.

Glucose lab tests rely on indicators from reactions with other substances, he said, “but you can’t do that in the body.” Measuring glucose in tears or urine is one possibility, he said, but the scarcity in those liquids poses a challenge: “Your body doesn’t want to spill glucose and lose energy.”

Dr. Rice himself explored a glucose-measuring technique that aimed to correlate glucose levels to the speed of the retina’s reaction to light. The idea was that patients would wear special glasses that would shine a light in the eye at the press of a button. The project ultimately failed.

There are other challenges, said Dr. Baers, the technology adviser. “Glucose concentrations in sweat or tears are not reflective of blood glucose concentrations. To make things even more challenging, glucose levels in these fluids are orders of magnitude smaller than that found in blood.”

And, she said, there’s a time lag between glucose levels in blood and in other body fluids. “This means that a sweat glucose level is really giving information from an hour previous, which can be dangerous if you’re operating machinery or driving.”

Wearable diabetes tech targets more than glucose

There’s more to wearable, noninvasive diabetes technology than glucose-monitoring. One of the new frontiers is diagnostics.

Earlier this year, researchers from the University of California at San Francisco and the digital startup Cardiogram reported that they were able to use data from digital heart rate sensors (like those found in Apple Watches, Fitbits and other devices) to correctly detect diabetes in patients.

In a study presented at the 2018 meeting of the Association for the Advancement of Artificial Intelligence, the researchers said they detected diabetes in 85% of 462 participants (out of a pool of 14,011) who’d previously been diagnosed with the condition (AAAAI abstract arXiv:1802.02511v1 [cs.LG]).

As tech advances, questions remain

San Diego’s Scripps Whittier Diabetes Institute is another player in the diabetes/digital health world. It’s currently working on several clinical trials of diabetes technology, including a study into whether older adults with type 1 diabetes will benefit from a continuous glucose monitoring device with a wireless connection.

[email protected]

SVS is accepting applications for Medical Editor of "Vascular Specialist," the monthly news periodical produced by SVS. The editor can expect to spend approximately 10-20 hours each month in the three weeks leading up to publication. A modest annual honorarium is provided. Previous editorial experience will be helpful. Please send letters of interest by April 15 to Kenneth M. Slaw, Ph.D., at [email protected]. He will forward your interest to the SVS Publications Committee for consideration. More information is in the March 29 issue of Pulse.

SVS is accepting applications for Medical Editor of "Vascular Specialist," the monthly news periodical produced by SVS. The editor can expect to spend approximately 10-20 hours each month in the three weeks leading up to publication. A modest annual honorarium is provided. Previous editorial experience will be helpful. Please send letters of interest by April 15 to Kenneth M. Slaw, Ph.D., at [email protected]. He will forward your interest to the SVS Publications Committee for consideration. More information is in the March 29 issue of Pulse.

SVS is accepting applications for Medical Editor of "Vascular Specialist," the monthly news periodical produced by SVS. The editor can expect to spend approximately 10-20 hours each month in the three weeks leading up to publication. A modest annual honorarium is provided. Previous editorial experience will be helpful. Please send letters of interest by April 15 to Kenneth M. Slaw, Ph.D., at [email protected]. He will forward your interest to the SVS Publications Committee for consideration. More information is in the March 29 issue of Pulse.

CHICAGO – When women with polycystic ovary syndrome (PCOS) took metformin during pregnancy, preterm births and late miscarriages were reduced, but researchers saw no effect on blood glucose levels or other diabetes-related maternal outcomes.

A Nordic study of pregnant women, dubbed PregMet 2, followed the course of 487 women with PCOS who were randomized to take 2,000 mg of metformin or placebo daily during pregnancy.

Kari Oakes/MDedge News

[email protected]

CHICAGO – When women with polycystic ovary syndrome (PCOS) took metformin during pregnancy, preterm births and late miscarriages were reduced, but researchers saw no effect on blood glucose levels or other diabetes-related maternal outcomes.

A Nordic study of pregnant women, dubbed PregMet 2, followed the course of 487 women with PCOS who were randomized to take 2,000 mg of metformin or placebo daily during pregnancy.

Kari Oakes/MDedge News

[email protected]

CHICAGO – When women with polycystic ovary syndrome (PCOS) took metformin during pregnancy, preterm births and late miscarriages were reduced, but researchers saw no effect on blood glucose levels or other diabetes-related maternal outcomes.

A Nordic study of pregnant women, dubbed PregMet 2, followed the course of 487 women with PCOS who were randomized to take 2,000 mg of metformin or placebo daily during pregnancy.

Kari Oakes/MDedge News

[email protected]

Background: The acuity of many patients recently discharged from an acute care facility is high. Some of these patients are being transferred to a SNF upon hospital discharge. Currently existing SNF care systems may not be prepared sufficiently for the challenges that arise with the admission of such patients to the SNFs after hospital discharge, resulting in readmissions.

Study design: Observational, retrospective cohort analysis.

Setting: Collaborative effort among a large, urban, acute care center, interdisciplinary clinical team, 124 community physicians, and eight SNFs.

Synopsis: In addition to standard care, the Enhanced Care Program (ECP) included a team of nurse practitioners participating in the care of SNF patients, a pharmacist-driven medication reconciliation at the time of transfer, and educational in-services for SNF nursing staff. Following introduction of the three ECP interventions, 30-day readmission rates were compared for both ECP and non-ECP patient groups. After adjustment for sociodemographic and clinical characteristics, ECP patients had 29% lower odds of being readmitted within 30 days (P less than .001). Multivariate analyses confirmed similar results. Major caveats include that this was a single-hospital study and that selection of the enrolled patients was not random, but rather, was determined by their primary care providers, potentially leading to some confounding.

Bottom line: For patients discharged to SNFs, an interdisciplinary care approach may reduce 30-day hospital readmissions.

Citation: Rosen BT et al. The Enhanced Care Program: Impact of a care transition program on 30-day hospital readmissions for patients discharged from an acute care facility to skilled nursing facilities. J Hosp Med. 2017 Oct 4:E1-E7. doi: 10.12788/jhm.2852

Dr. Burklin is assistant professor of medicine in the division of hospital medicine, Emory University, Atlanta.

Background: The acuity of many patients recently discharged from an acute care facility is high. Some of these patients are being transferred to a SNF upon hospital discharge. Currently existing SNF care systems may not be prepared sufficiently for the challenges that arise with the admission of such patients to the SNFs after hospital discharge, resulting in readmissions.

Study design: Observational, retrospective cohort analysis.

Setting: Collaborative effort among a large, urban, acute care center, interdisciplinary clinical team, 124 community physicians, and eight SNFs.

Synopsis: In addition to standard care, the Enhanced Care Program (ECP) included a team of nurse practitioners participating in the care of SNF patients, a pharmacist-driven medication reconciliation at the time of transfer, and educational in-services for SNF nursing staff. Following introduction of the three ECP interventions, 30-day readmission rates were compared for both ECP and non-ECP patient groups. After adjustment for sociodemographic and clinical characteristics, ECP patients had 29% lower odds of being readmitted within 30 days (P less than .001). Multivariate analyses confirmed similar results. Major caveats include that this was a single-hospital study and that selection of the enrolled patients was not random, but rather, was determined by their primary care providers, potentially leading to some confounding.

Bottom line: For patients discharged to SNFs, an interdisciplinary care approach may reduce 30-day hospital readmissions.

Citation: Rosen BT et al. The Enhanced Care Program: Impact of a care transition program on 30-day hospital readmissions for patients discharged from an acute care facility to skilled nursing facilities. J Hosp Med. 2017 Oct 4:E1-E7. doi: 10.12788/jhm.2852

Dr. Burklin is assistant professor of medicine in the division of hospital medicine, Emory University, Atlanta.

Background: The acuity of many patients recently discharged from an acute care facility is high. Some of these patients are being transferred to a SNF upon hospital discharge. Currently existing SNF care systems may not be prepared sufficiently for the challenges that arise with the admission of such patients to the SNFs after hospital discharge, resulting in readmissions.

Study design: Observational, retrospective cohort analysis.

Setting: Collaborative effort among a large, urban, acute care center, interdisciplinary clinical team, 124 community physicians, and eight SNFs.

Synopsis: In addition to standard care, the Enhanced Care Program (ECP) included a team of nurse practitioners participating in the care of SNF patients, a pharmacist-driven medication reconciliation at the time of transfer, and educational in-services for SNF nursing staff. Following introduction of the three ECP interventions, 30-day readmission rates were compared for both ECP and non-ECP patient groups. After adjustment for sociodemographic and clinical characteristics, ECP patients had 29% lower odds of being readmitted within 30 days (P less than .001). Multivariate analyses confirmed similar results. Major caveats include that this was a single-hospital study and that selection of the enrolled patients was not random, but rather, was determined by their primary care providers, potentially leading to some confounding.

Bottom line: For patients discharged to SNFs, an interdisciplinary care approach may reduce 30-day hospital readmissions.

Citation: Rosen BT et al. The Enhanced Care Program: Impact of a care transition program on 30-day hospital readmissions for patients discharged from an acute care facility to skilled nursing facilities. J Hosp Med. 2017 Oct 4:E1-E7. doi: 10.12788/jhm.2852

Dr. Burklin is assistant professor of medicine in the division of hospital medicine, Emory University, Atlanta.

The prevalence of gallstones is approximately 10% to 15% of the adult US population.^1,2 Most cases are asymptomatic, as gallstones are usually discovered incidentally during routine imaging for other abdominal conditions, and only about 20% of patients with asymptomatic gallstones develop clinically significant complications.^2,3

Nevertheless, gallstones carry significant healthcare costs. In 2004, the median inpatient cost for any gallstone-related disease was $11,584, with an overall annual cost of $6.2 billion.^4,5

Laparoscopic cholecystectomy is the standard treatment for symptomatic cholelithiasis. For asymptomatic cholelithasis, the usual approach is expectant management (“watch and wait”), but prophylactic cholecystectomy may be an option in certain patients at high risk.

CHEMICAL COMPOSITION

Gallstones can be classified into 2 main categories based on their predominant chemical composition: cholesterol or pigment.

Cholesterol gallstones

About 75% of gallstones are composed of cholesterol.^3,4 In the past, this type of stone was thought to be caused by gallbladder inflammation, bile stasis, and absorption of bile salts from damaged mucosa. However, it is now known that cholesterol gallstones are the result of biliary supersaturation caused by cholesterol hypersecretion into the gallbladder, gallbladder hypomotility, accelerated cholesterol nucleation and crystallization, and mucin gel accumulation.

Pigment gallstones

Black pigment gallstones account for 10% to 15% of all gallstones.⁶ They are caused by chronic hemolysis in association with supersaturation of bile with calcium hydrogen bilirubinate, along with deposition of calcium carbonate, phosphate, and inorganic salts.⁷

Brown pigment stones, accounting for 5% to 10% of all gallstones,⁶ are caused by infection in the obstructed bile ducts, where bacteria that produce beta-glucuronidase, phospholipase, and slime contribute to formation of the stone.^8,9

RISK FACTORS FOR GALLSTONES

Age. After age 40, the risk increases dramatically, with an incidence 4 times higher for those ages 40 to 69 than in younger people.¹⁰

Female sex. Women of reproductive age are 4 times more likely to develop gallstones than men, but this gap narrows after menopause.¹¹ The higher risk is attributed to female sex hormones, pregnancy, and oral contraceptive use. Estrogen decreases secretion of bile salts and increases secretion of cholesterol into the gallbladder, which leads to cholesterol supersaturation. Progesterone acts synergistically by causing hypomobility of the gallbladder, which in turn leads to bile stasis.^12,13

Ethnicity. The risk is higher in Mexican Americans and Native Americans than in other ethnic groups.¹⁴

Rapid weight loss, such as after bariatric surgery, occurs from decreased caloric intake and promotes bile stasis, while lipolysis increases cholesterol mobilization and secretion into the gallbladder. This creates an environment conducive to bile supersaturation with cholesterol, leading to gallstone formation.

Chronic hemolytic disorders carry an increased risk of developing calcium bilirubinate stones due to increased excretion of bilirubin during hemolysis.

Obesity and diabetes mellitus are both attributed to insulin resistance. Obesity also increases bile stasis and cholesterol saturation.

Most patients with gallstones (cholelithiasis) experience no symptoms. Their gallstones are often discovered incidentally during imaging tests for unrelated or unexplained abdominal symptoms. Most patients with asymptomatic gallstones remain symptom-free, while about 20% develop gallstone-related symptoms.^2,3

Abdominal pain is the most common symptom. The phrase biliary colic—suggesting pain that is fluctuating in nature—appears ubiquitously in the medical literature, but it does not correctly characterize the pain associated with gallstones.

Most patients with gallstone symptoms describe a constant and often severe pain in the right upper abdomen, epigastrium, or both, often persisting for 30 to 120 minutes. Symptoms are frequently reported in the epigastrium when only visceral pain fibers are stimulated due to gallbladder distention. This is usually called midline pain; however, pain occurs in the back and right shoulder in up to 60% of patients, with involvement of somatic fibers.^15,16 Gallstone pain is not relieved by change of position or passage of stool or gas.

Onset of symptoms more than an hour after eating or in the late evening or at night also  very strongly suggests biliary pain. Patients with a history of biliary pain are more likely to experience it again, with a 69% chance of developing recurrent pain within 2 years.¹⁷

GALLSTONE-RELATED COMPLICATIONS

Acute gallbladder inflammation (cholecystitis)

Gallbladder inflammation (cholecystitis) is the most common complication, occurring in up to 10% of symptomatic cases. Many patients with acute cholecystitis present with right upper quadrant pain that may be accompanied by anorexia, nausea, or vomiting. Inspiratory arrest on deep palpation of the right upper quadrant (Murphy sign) has a specificity of 79% to 96% for acute cholecystitis.²⁰ Markers of systemic inflammation such as fever, elevated white blood cell count, and elevated C-reactive protein are highly suggestive of acute cholecystitis.^20,21

Bile duct stones (choledocholithiasis)

Bile duct stones (choledocholithiasis) are detected in 3.4% to 12% of patients with gallstones.^22,23 Most stones in the common bile duct migrate there from the gallbladder via the cystic duct. Less commonly, primary duct stones form in the duct due to biliary stasis. Removing the gallbladder does not completely eliminate the risk of bile duct stones, as stones can remain or recur after surgery.

Bile duct stones can obstruct the common bile duct, which disrupts normal bile flow and leads to jaundice. Other symptoms may include pruritus, right upper quadrant pain, nausea, and vomiting. Serum levels of bilirubin, aspartate aminotransferase, alanine aminotransferase (ALT), and alkaline phosphatase are usually high.²⁴

Acute bacterial infection (cholangitis)

Acute bacterial infection of the biliary system (cholangitis) is usually associated with obstruction of the common bile duct. Common symptoms of acute cholangitis include right upper quadrant pain, fever, and jaundice (Charcot triad), and these are present in about 50% to 75% of cases.²¹ In severe cases, patients can develop altered mental status and septicemic shock in addition to the Charcot triad, a condition called the Reynold pentad. White blood cell counts and serum levels of C-reactive protein, bilirubin, aminotransferases, and alkaline phosphatase are usually elevated.²¹

Pancreatitis

Approximately 4% to 8% of patients with gallstones develop inflammation of the pancreas (pancreatitis).²⁵ The diagnosis of acute pancreatitis requires at least 2 of the following:^26,27

• Abdominal pain (typically epigastric, often radiating to the back)
• Amylase or lipase levels at least 3 times above the normal limit
• Imaging findings that suggest acute pancreatitis.

Gallstone-related pancreatitis should be considered if the ALT level is greater than 150 U/mL, which has a 97% specificity for gallstone-related pancreatitis.²⁸

Transabdominal ultrasonography, with a sensitivity of 84% to 89% and a specificity of up to 99%, is the test of choice for detecting gallstones.²⁹ The characteristic findings of acute cholecystitis on ultrasonography include enlargement of the gallbladder, thickening of the gallbladder wall, presence of pericholecystic fluid, and tenderness elicited by the ultrasound probe over the gallbladder (sonographic Murphy sign).

Scintigraphy as a second test

Acute cholecystitis is primarily a clinical diagnosis and typically does not require additional imaging beyond ultrasonography. When there is discordance between clinical and ultrasonographic findings, the most accurate second imaging test is scintigraphy of the biliary tract, usually performed with technetium-labeled hydroxy iminodiacetic acid. Given intravenously, the radionuclide is rapidly taken up by the liver and then secreted into the bile. In acute cholecystitis, the cystic duct is functionally occluded and the isotope does not enter the gallbladder, creating an imaging void compared with a normal appearance.

Scintigraphy is more sensitive than abdominal ultrasonography, with a sensitivity of up to 97% vs 81% to 88%, respectively.^29,30 The tests have about equal specificity.

Even though scintigraphy is more sensitive, abdominal ultrasonography is often the initial test for patients with suspected acute cholecystitis because it is more widely available, takes less time, does not involve radiation exposure, and can assess for the presence or absence of gallstones and dilation of the intra- and extrahepatic bile ducts.

Looking for stones in the common bile duct

When acute cholangitis due to choledocholithiasis is suspected, abdominal ultrasonography is a prudent initial test to look for gallstones or biliary dilation suggesting obstruction by stones in the common bile duct. Abdominal ultrasonography has only a 22% to 55% sensitivity for visualizing stones in the common bile duct, but it has a 77% to 87% sensitivity for detecting common bile duct dilation, a surrogate marker of stones.³¹

The normal bile duct diameter ranges from 3 to 6 mm, although mild dilation is often seen in older patients or after cholecystectomy or Roux-en-Y gastric bypass surgery.^32,33 Bile duct dilation of up to 10 mm can be considered normal in patients after cholecystectomy.³⁴ A normal-appearing bile duct on ultrasonography has a negative predictive value of 95% for excluding common bile duct stones.³¹

Endoscopic ultrasonography (EUS), magnetic resonance cholangiopancreatography (MRCP), and endoscopic retrograde cholangiopancreatography (ERCP) have similar sensitivity (89%–94%, 85%–92%, and 89%–93%, respectively) and specificity (94%–95%, 93%–97%, and 100%, respectively) for detecting common bile duct stones.^35–37 EUS is superior to MRCP in detecting stones smaller than 6 mm.³⁸

ERCP should be reserved for managing rather than diagnosing common bile duct stones because of the risk of pancreatitis and perforation. Patients undergoing cholecystectomy who are suspected of having choledocholithiasis may undergo intraoperative cholangiography or laparoscopic common bile duct ultrasonography.

WATCH AND WAIT, OR INTERVENE?

Asymptomatic gallstones

Standard treatment for these patients is expectant management. Cholecystectomy is not recommended for patients with asymptomatic gallstones.⁴⁷ Nevertheless, some patients may benefit from prophylactic cholecystectomy. We and others⁴⁸ suggest considering cholecystectomy in the following patients.

Patients with chronic hemolytic anemia (including children with sickle cell anemia and spherocytosis). These patients have a higher risk of developing calcium bilirubinate stones, and cholecystectomy has improved outcomes.⁴⁹ It should be noted that most of these data come from pediatric populations and have been extrapolated to adults.

Native Americans, who have a higher risk of gallbladder cancer if they have gallstones.^2,50

Conversely, calcification of the gallbladder wall (“porcelain gallbladder”) is no longer considered an absolute indication for cholecystectomy. This condition was thought to be associated with a high rate of gallbladder carcinoma, but analyses of larger, more recent data sets found much smaller risks.^51,52 Further, cholecystectomy in these patients was found to be associated with high rates of postoperative complications. Thus, prophylactic cholecystectomy is no longer recommended in asymptomatic cases of porcelain gallbladder.

In addition, concomitant cholecystectomy in patients undergoing bariatric surgery is no longer considered the therapeutic standard. Historically, cholecystectomy was performed in these patients because of the increased risk of gallstones associated with rapid weight loss after surgery. However, research now weighs against concomitant cholecystectomy with bariatric surgery and most other abdominal surgeries for asymptomatic gallstones.⁵³

Based on information in reference 48.

For patients experiencing acute cholecystitis, laparoscopic cholecystectomy within 72 hours is recommended.⁴⁸ There were safety concerns regarding higher rates of morbidity and conversion from laparoscopic to open cholecystectomy in patients who underwent surgery before the acute cholecystitis episode had settled. However, a large meta-analysis found no significant difference between early and delayed laparoscopic cholecystectomy in bile duct injury or conversion rates.⁵⁴ Further, early cholecystectomy—defined as within 1 week of symptom onset—has been found to reduce gallstone-related complications, shorten hospital stays, and lower costs.^55–57 If the patient cannot undergo surgery, percutaneous cholecystotomy or novel endoscopic gallbladder drainage interventions can be used.

Reprinted from ASGE Standards of Practice Committee; Maple JT, Ben-Menachem T, Anderson MA, et al. The role of endoscopy in the evaluation of suspected choledocholithiasis. Gastrointest Endoscp 2010; 71:1–9 with permission from Elsevier.

Several variables predict the presence of bile duct stones in patients who have symptoms (Table 4). Based on these predictors, the ASGE classifies the probabilities as low (< 10%), intermediate (10% to 50%), and high (> 50%)³¹:

• 
  Low-risk patients require no further evaluation of the common bile duct
• High-risk patients should undergo preoperative ERCP and stone extraction if needed
• Intermediate-risk patients should undergo preoperative imaging with EUS or MRCP or intraoperative bile duct evaluation, depending on the availability, costs, and local expertise.

Patients with associated cholangitis should be given intravenous fluids and broad-spectrum antibiotics. Biliary decompression should be done as early as possible to decrease the risk of morbidity and mortality. For acute cholangitis, ERCP is the treatment of choice.²⁵

Patients with acute gallstone pancreatitis should receive conservative management with intravenous isotonic solutions and pain control, followed by laparoscopic cholecystectomy.⁴⁸

The timing of laparoscopic cholecystectomy in acute gallstone pancreatitis has been debated. Studies conducted during the era of open cholecystectomy reported similar or worse outcomes if cholecystectomy was done sooner rather than later.

However, in 1999, Uhl et al⁵⁸ reported that 48 of 77 patients admitted with acute gallstone pancreatitis were able to undergo laparoscopic cholecystectomy during the same admission. Success rates were 85% (30 of 35 patients) in those with mild disease and 62% (8 of 13 patients) in those with severe disease. They concluded laparoscopic cholecystectomy could be safely performed within 7 days in patients with mild disease, whereas in severe disease at least 3 weeks should elapse because of the risk of infection.

In a randomized trial published in 2010, Aboulian et al⁵⁹ reported that hospital length of stay (the primary end point) was shorter in 25 patients who underwent laparoscopic cholecystectomy early (within 48 hours of admission) than in 25 patients who underwent surgery after abdominal pain had resolved and laboratory enzymes showed a normalizing trend, 3.5 vs 5.8 days (P = .0016). Rates of perioperative complications and need for conversion to open surgery were similar between the 2 groups.

If there is associated cholangitis, patients should also be given broad-spectrum antibiotics and should undergo ERCP within 24 hours of admission.^25–27

SUMMARY

Gallstones are common in US adults. Abdominal ultrasonography is the diagnostic imaging test of choice to detect gallbladder stones and assess for findings suggestive of acute cholecystitis and dilation of the common bile duct. Fortunately, most gallstones are asymptomatic and can usually be managed expectantly. In patients who have symptoms or have gallstone complications, laparoscopic cholecystectomy is the standard of care.

The prevalence of gallstones is approximately 10% to 15% of the adult US population.^1,2 Most cases are asymptomatic, as gallstones are usually discovered incidentally during routine imaging for other abdominal conditions, and only about 20% of patients with asymptomatic gallstones develop clinically significant complications.^2,3

Nevertheless, gallstones carry significant healthcare costs. In 2004, the median inpatient cost for any gallstone-related disease was $11,584, with an overall annual cost of $6.2 billion.^4,5

Laparoscopic cholecystectomy is the standard treatment for symptomatic cholelithiasis. For asymptomatic cholelithasis, the usual approach is expectant management (“watch and wait”), but prophylactic cholecystectomy may be an option in certain patients at high risk.

CHEMICAL COMPOSITION

Gallstones can be classified into 2 main categories based on their predominant chemical composition: cholesterol or pigment.

Cholesterol gallstones

About 75% of gallstones are composed of cholesterol.^3,4 In the past, this type of stone was thought to be caused by gallbladder inflammation, bile stasis, and absorption of bile salts from damaged mucosa. However, it is now known that cholesterol gallstones are the result of biliary supersaturation caused by cholesterol hypersecretion into the gallbladder, gallbladder hypomotility, accelerated cholesterol nucleation and crystallization, and mucin gel accumulation.

Pigment gallstones

Black pigment gallstones account for 10% to 15% of all gallstones.⁶ They are caused by chronic hemolysis in association with supersaturation of bile with calcium hydrogen bilirubinate, along with deposition of calcium carbonate, phosphate, and inorganic salts.⁷

Brown pigment stones, accounting for 5% to 10% of all gallstones,⁶ are caused by infection in the obstructed bile ducts, where bacteria that produce beta-glucuronidase, phospholipase, and slime contribute to formation of the stone.^8,9

RISK FACTORS FOR GALLSTONES

Age. After age 40, the risk increases dramatically, with an incidence 4 times higher for those ages 40 to 69 than in younger people.¹⁰

Female sex. Women of reproductive age are 4 times more likely to develop gallstones than men, but this gap narrows after menopause.¹¹ The higher risk is attributed to female sex hormones, pregnancy, and oral contraceptive use. Estrogen decreases secretion of bile salts and increases secretion of cholesterol into the gallbladder, which leads to cholesterol supersaturation. Progesterone acts synergistically by causing hypomobility of the gallbladder, which in turn leads to bile stasis.^12,13

Ethnicity. The risk is higher in Mexican Americans and Native Americans than in other ethnic groups.¹⁴

Rapid weight loss, such as after bariatric surgery, occurs from decreased caloric intake and promotes bile stasis, while lipolysis increases cholesterol mobilization and secretion into the gallbladder. This creates an environment conducive to bile supersaturation with cholesterol, leading to gallstone formation.

Chronic hemolytic disorders carry an increased risk of developing calcium bilirubinate stones due to increased excretion of bilirubin during hemolysis.

Obesity and diabetes mellitus are both attributed to insulin resistance. Obesity also increases bile stasis and cholesterol saturation.

Most patients with gallstones (cholelithiasis) experience no symptoms. Their gallstones are often discovered incidentally during imaging tests for unrelated or unexplained abdominal symptoms. Most patients with asymptomatic gallstones remain symptom-free, while about 20% develop gallstone-related symptoms.^2,3

Abdominal pain is the most common symptom. The phrase biliary colic—suggesting pain that is fluctuating in nature—appears ubiquitously in the medical literature, but it does not correctly characterize the pain associated with gallstones.

Most patients with gallstone symptoms describe a constant and often severe pain in the right upper abdomen, epigastrium, or both, often persisting for 30 to 120 minutes. Symptoms are frequently reported in the epigastrium when only visceral pain fibers are stimulated due to gallbladder distention. This is usually called midline pain; however, pain occurs in the back and right shoulder in up to 60% of patients, with involvement of somatic fibers.^15,16 Gallstone pain is not relieved by change of position or passage of stool or gas.

Onset of symptoms more than an hour after eating or in the late evening or at night also  very strongly suggests biliary pain. Patients with a history of biliary pain are more likely to experience it again, with a 69% chance of developing recurrent pain within 2 years.¹⁷

GALLSTONE-RELATED COMPLICATIONS

Acute gallbladder inflammation (cholecystitis)

Gallbladder inflammation (cholecystitis) is the most common complication, occurring in up to 10% of symptomatic cases. Many patients with acute cholecystitis present with right upper quadrant pain that may be accompanied by anorexia, nausea, or vomiting. Inspiratory arrest on deep palpation of the right upper quadrant (Murphy sign) has a specificity of 79% to 96% for acute cholecystitis.²⁰ Markers of systemic inflammation such as fever, elevated white blood cell count, and elevated C-reactive protein are highly suggestive of acute cholecystitis.^20,21

Bile duct stones (choledocholithiasis)

Bile duct stones (choledocholithiasis) are detected in 3.4% to 12% of patients with gallstones.^22,23 Most stones in the common bile duct migrate there from the gallbladder via the cystic duct. Less commonly, primary duct stones form in the duct due to biliary stasis. Removing the gallbladder does not completely eliminate the risk of bile duct stones, as stones can remain or recur after surgery.

Bile duct stones can obstruct the common bile duct, which disrupts normal bile flow and leads to jaundice. Other symptoms may include pruritus, right upper quadrant pain, nausea, and vomiting. Serum levels of bilirubin, aspartate aminotransferase, alanine aminotransferase (ALT), and alkaline phosphatase are usually high.²⁴

Acute bacterial infection (cholangitis)

Acute bacterial infection of the biliary system (cholangitis) is usually associated with obstruction of the common bile duct. Common symptoms of acute cholangitis include right upper quadrant pain, fever, and jaundice (Charcot triad), and these are present in about 50% to 75% of cases.²¹ In severe cases, patients can develop altered mental status and septicemic shock in addition to the Charcot triad, a condition called the Reynold pentad. White blood cell counts and serum levels of C-reactive protein, bilirubin, aminotransferases, and alkaline phosphatase are usually elevated.²¹

Pancreatitis

Approximately 4% to 8% of patients with gallstones develop inflammation of the pancreas (pancreatitis).²⁵ The diagnosis of acute pancreatitis requires at least 2 of the following:^26,27

• Abdominal pain (typically epigastric, often radiating to the back)
• Amylase or lipase levels at least 3 times above the normal limit
• Imaging findings that suggest acute pancreatitis.

Gallstone-related pancreatitis should be considered if the ALT level is greater than 150 U/mL, which has a 97% specificity for gallstone-related pancreatitis.²⁸

Transabdominal ultrasonography, with a sensitivity of 84% to 89% and a specificity of up to 99%, is the test of choice for detecting gallstones.²⁹ The characteristic findings of acute cholecystitis on ultrasonography include enlargement of the gallbladder, thickening of the gallbladder wall, presence of pericholecystic fluid, and tenderness elicited by the ultrasound probe over the gallbladder (sonographic Murphy sign).

Scintigraphy as a second test

Acute cholecystitis is primarily a clinical diagnosis and typically does not require additional imaging beyond ultrasonography. When there is discordance between clinical and ultrasonographic findings, the most accurate second imaging test is scintigraphy of the biliary tract, usually performed with technetium-labeled hydroxy iminodiacetic acid. Given intravenously, the radionuclide is rapidly taken up by the liver and then secreted into the bile. In acute cholecystitis, the cystic duct is functionally occluded and the isotope does not enter the gallbladder, creating an imaging void compared with a normal appearance.

Scintigraphy is more sensitive than abdominal ultrasonography, with a sensitivity of up to 97% vs 81% to 88%, respectively.^29,30 The tests have about equal specificity.

Even though scintigraphy is more sensitive, abdominal ultrasonography is often the initial test for patients with suspected acute cholecystitis because it is more widely available, takes less time, does not involve radiation exposure, and can assess for the presence or absence of gallstones and dilation of the intra- and extrahepatic bile ducts.

Looking for stones in the common bile duct

When acute cholangitis due to choledocholithiasis is suspected, abdominal ultrasonography is a prudent initial test to look for gallstones or biliary dilation suggesting obstruction by stones in the common bile duct. Abdominal ultrasonography has only a 22% to 55% sensitivity for visualizing stones in the common bile duct, but it has a 77% to 87% sensitivity for detecting common bile duct dilation, a surrogate marker of stones.³¹

The normal bile duct diameter ranges from 3 to 6 mm, although mild dilation is often seen in older patients or after cholecystectomy or Roux-en-Y gastric bypass surgery.^32,33 Bile duct dilation of up to 10 mm can be considered normal in patients after cholecystectomy.³⁴ A normal-appearing bile duct on ultrasonography has a negative predictive value of 95% for excluding common bile duct stones.³¹

Endoscopic ultrasonography (EUS), magnetic resonance cholangiopancreatography (MRCP), and endoscopic retrograde cholangiopancreatography (ERCP) have similar sensitivity (89%–94%, 85%–92%, and 89%–93%, respectively) and specificity (94%–95%, 93%–97%, and 100%, respectively) for detecting common bile duct stones.^35–37 EUS is superior to MRCP in detecting stones smaller than 6 mm.³⁸

ERCP should be reserved for managing rather than diagnosing common bile duct stones because of the risk of pancreatitis and perforation. Patients undergoing cholecystectomy who are suspected of having choledocholithiasis may undergo intraoperative cholangiography or laparoscopic common bile duct ultrasonography.

WATCH AND WAIT, OR INTERVENE?

Asymptomatic gallstones

Standard treatment for these patients is expectant management. Cholecystectomy is not recommended for patients with asymptomatic gallstones.⁴⁷ Nevertheless, some patients may benefit from prophylactic cholecystectomy. We and others⁴⁸ suggest considering cholecystectomy in the following patients.

Patients with chronic hemolytic anemia (including children with sickle cell anemia and spherocytosis). These patients have a higher risk of developing calcium bilirubinate stones, and cholecystectomy has improved outcomes.⁴⁹ It should be noted that most of these data come from pediatric populations and have been extrapolated to adults.

Native Americans, who have a higher risk of gallbladder cancer if they have gallstones.^2,50

Conversely, calcification of the gallbladder wall (“porcelain gallbladder”) is no longer considered an absolute indication for cholecystectomy. This condition was thought to be associated with a high rate of gallbladder carcinoma, but analyses of larger, more recent data sets found much smaller risks.^51,52 Further, cholecystectomy in these patients was found to be associated with high rates of postoperative complications. Thus, prophylactic cholecystectomy is no longer recommended in asymptomatic cases of porcelain gallbladder.

In addition, concomitant cholecystectomy in patients undergoing bariatric surgery is no longer considered the therapeutic standard. Historically, cholecystectomy was performed in these patients because of the increased risk of gallstones associated with rapid weight loss after surgery. However, research now weighs against concomitant cholecystectomy with bariatric surgery and most other abdominal surgeries for asymptomatic gallstones.⁵³

Based on information in reference 48.

For patients experiencing acute cholecystitis, laparoscopic cholecystectomy within 72 hours is recommended.⁴⁸ There were safety concerns regarding higher rates of morbidity and conversion from laparoscopic to open cholecystectomy in patients who underwent surgery before the acute cholecystitis episode had settled. However, a large meta-analysis found no significant difference between early and delayed laparoscopic cholecystectomy in bile duct injury or conversion rates.⁵⁴ Further, early cholecystectomy—defined as within 1 week of symptom onset—has been found to reduce gallstone-related complications, shorten hospital stays, and lower costs.^55–57 If the patient cannot undergo surgery, percutaneous cholecystotomy or novel endoscopic gallbladder drainage interventions can be used.

Reprinted from ASGE Standards of Practice Committee; Maple JT, Ben-Menachem T, Anderson MA, et al. The role of endoscopy in the evaluation of suspected choledocholithiasis. Gastrointest Endoscp 2010; 71:1–9 with permission from Elsevier.

Several variables predict the presence of bile duct stones in patients who have symptoms (Table 4). Based on these predictors, the ASGE classifies the probabilities as low (< 10%), intermediate (10% to 50%), and high (> 50%)³¹:

• 
  Low-risk patients require no further evaluation of the common bile duct
• High-risk patients should undergo preoperative ERCP and stone extraction if needed
• Intermediate-risk patients should undergo preoperative imaging with EUS or MRCP or intraoperative bile duct evaluation, depending on the availability, costs, and local expertise.

Patients with associated cholangitis should be given intravenous fluids and broad-spectrum antibiotics. Biliary decompression should be done as early as possible to decrease the risk of morbidity and mortality. For acute cholangitis, ERCP is the treatment of choice.²⁵

Patients with acute gallstone pancreatitis should receive conservative management with intravenous isotonic solutions and pain control, followed by laparoscopic cholecystectomy.⁴⁸

The timing of laparoscopic cholecystectomy in acute gallstone pancreatitis has been debated. Studies conducted during the era of open cholecystectomy reported similar or worse outcomes if cholecystectomy was done sooner rather than later.

However, in 1999, Uhl et al⁵⁸ reported that 48 of 77 patients admitted with acute gallstone pancreatitis were able to undergo laparoscopic cholecystectomy during the same admission. Success rates were 85% (30 of 35 patients) in those with mild disease and 62% (8 of 13 patients) in those with severe disease. They concluded laparoscopic cholecystectomy could be safely performed within 7 days in patients with mild disease, whereas in severe disease at least 3 weeks should elapse because of the risk of infection.

In a randomized trial published in 2010, Aboulian et al⁵⁹ reported that hospital length of stay (the primary end point) was shorter in 25 patients who underwent laparoscopic cholecystectomy early (within 48 hours of admission) than in 25 patients who underwent surgery after abdominal pain had resolved and laboratory enzymes showed a normalizing trend, 3.5 vs 5.8 days (P = .0016). Rates of perioperative complications and need for conversion to open surgery were similar between the 2 groups.

If there is associated cholangitis, patients should also be given broad-spectrum antibiotics and should undergo ERCP within 24 hours of admission.^25–27

SUMMARY

Gallstones are common in US adults. Abdominal ultrasonography is the diagnostic imaging test of choice to detect gallbladder stones and assess for findings suggestive of acute cholecystitis and dilation of the common bile duct. Fortunately, most gallstones are asymptomatic and can usually be managed expectantly. In patients who have symptoms or have gallstone complications, laparoscopic cholecystectomy is the standard of care.

The prevalence of gallstones is approximately 10% to 15% of the adult US population.^1,2 Most cases are asymptomatic, as gallstones are usually discovered incidentally during routine imaging for other abdominal conditions, and only about 20% of patients with asymptomatic gallstones develop clinically significant complications.^2,3

Nevertheless, gallstones carry significant healthcare costs. In 2004, the median inpatient cost for any gallstone-related disease was $11,584, with an overall annual cost of $6.2 billion.^4,5

Laparoscopic cholecystectomy is the standard treatment for symptomatic cholelithiasis. For asymptomatic cholelithasis, the usual approach is expectant management (“watch and wait”), but prophylactic cholecystectomy may be an option in certain patients at high risk.

CHEMICAL COMPOSITION

Gallstones can be classified into 2 main categories based on their predominant chemical composition: cholesterol or pigment.

Cholesterol gallstones

About 75% of gallstones are composed of cholesterol.^3,4 In the past, this type of stone was thought to be caused by gallbladder inflammation, bile stasis, and absorption of bile salts from damaged mucosa. However, it is now known that cholesterol gallstones are the result of biliary supersaturation caused by cholesterol hypersecretion into the gallbladder, gallbladder hypomotility, accelerated cholesterol nucleation and crystallization, and mucin gel accumulation.

Pigment gallstones

Black pigment gallstones account for 10% to 15% of all gallstones.⁶ They are caused by chronic hemolysis in association with supersaturation of bile with calcium hydrogen bilirubinate, along with deposition of calcium carbonate, phosphate, and inorganic salts.⁷

Brown pigment stones, accounting for 5% to 10% of all gallstones,⁶ are caused by infection in the obstructed bile ducts, where bacteria that produce beta-glucuronidase, phospholipase, and slime contribute to formation of the stone.^8,9

RISK FACTORS FOR GALLSTONES

Age. After age 40, the risk increases dramatically, with an incidence 4 times higher for those ages 40 to 69 than in younger people.¹⁰

Female sex. Women of reproductive age are 4 times more likely to develop gallstones than men, but this gap narrows after menopause.¹¹ The higher risk is attributed to female sex hormones, pregnancy, and oral contraceptive use. Estrogen decreases secretion of bile salts and increases secretion of cholesterol into the gallbladder, which leads to cholesterol supersaturation. Progesterone acts synergistically by causing hypomobility of the gallbladder, which in turn leads to bile stasis.^12,13

Ethnicity. The risk is higher in Mexican Americans and Native Americans than in other ethnic groups.¹⁴

Rapid weight loss, such as after bariatric surgery, occurs from decreased caloric intake and promotes bile stasis, while lipolysis increases cholesterol mobilization and secretion into the gallbladder. This creates an environment conducive to bile supersaturation with cholesterol, leading to gallstone formation.

Chronic hemolytic disorders carry an increased risk of developing calcium bilirubinate stones due to increased excretion of bilirubin during hemolysis.

Obesity and diabetes mellitus are both attributed to insulin resistance. Obesity also increases bile stasis and cholesterol saturation.

Most patients with gallstones (cholelithiasis) experience no symptoms. Their gallstones are often discovered incidentally during imaging tests for unrelated or unexplained abdominal symptoms. Most patients with asymptomatic gallstones remain symptom-free, while about 20% develop gallstone-related symptoms.^2,3

Abdominal pain is the most common symptom. The phrase biliary colic—suggesting pain that is fluctuating in nature—appears ubiquitously in the medical literature, but it does not correctly characterize the pain associated with gallstones.

Most patients with gallstone symptoms describe a constant and often severe pain in the right upper abdomen, epigastrium, or both, often persisting for 30 to 120 minutes. Symptoms are frequently reported in the epigastrium when only visceral pain fibers are stimulated due to gallbladder distention. This is usually called midline pain; however, pain occurs in the back and right shoulder in up to 60% of patients, with involvement of somatic fibers.^15,16 Gallstone pain is not relieved by change of position or passage of stool or gas.

Onset of symptoms more than an hour after eating or in the late evening or at night also  very strongly suggests biliary pain. Patients with a history of biliary pain are more likely to experience it again, with a 69% chance of developing recurrent pain within 2 years.¹⁷

GALLSTONE-RELATED COMPLICATIONS

Acute gallbladder inflammation (cholecystitis)

Gallbladder inflammation (cholecystitis) is the most common complication, occurring in up to 10% of symptomatic cases. Many patients with acute cholecystitis present with right upper quadrant pain that may be accompanied by anorexia, nausea, or vomiting. Inspiratory arrest on deep palpation of the right upper quadrant (Murphy sign) has a specificity of 79% to 96% for acute cholecystitis.²⁰ Markers of systemic inflammation such as fever, elevated white blood cell count, and elevated C-reactive protein are highly suggestive of acute cholecystitis.^20,21

Bile duct stones (choledocholithiasis)

Bile duct stones (choledocholithiasis) are detected in 3.4% to 12% of patients with gallstones.^22,23 Most stones in the common bile duct migrate there from the gallbladder via the cystic duct. Less commonly, primary duct stones form in the duct due to biliary stasis. Removing the gallbladder does not completely eliminate the risk of bile duct stones, as stones can remain or recur after surgery.

Bile duct stones can obstruct the common bile duct, which disrupts normal bile flow and leads to jaundice. Other symptoms may include pruritus, right upper quadrant pain, nausea, and vomiting. Serum levels of bilirubin, aspartate aminotransferase, alanine aminotransferase (ALT), and alkaline phosphatase are usually high.²⁴

Acute bacterial infection (cholangitis)

Acute bacterial infection of the biliary system (cholangitis) is usually associated with obstruction of the common bile duct. Common symptoms of acute cholangitis include right upper quadrant pain, fever, and jaundice (Charcot triad), and these are present in about 50% to 75% of cases.²¹ In severe cases, patients can develop altered mental status and septicemic shock in addition to the Charcot triad, a condition called the Reynold pentad. White blood cell counts and serum levels of C-reactive protein, bilirubin, aminotransferases, and alkaline phosphatase are usually elevated.²¹

Pancreatitis

Approximately 4% to 8% of patients with gallstones develop inflammation of the pancreas (pancreatitis).²⁵ The diagnosis of acute pancreatitis requires at least 2 of the following:^26,27

• Abdominal pain (typically epigastric, often radiating to the back)
• Amylase or lipase levels at least 3 times above the normal limit
• Imaging findings that suggest acute pancreatitis.

Gallstone-related pancreatitis should be considered if the ALT level is greater than 150 U/mL, which has a 97% specificity for gallstone-related pancreatitis.²⁸

Transabdominal ultrasonography, with a sensitivity of 84% to 89% and a specificity of up to 99%, is the test of choice for detecting gallstones.²⁹ The characteristic findings of acute cholecystitis on ultrasonography include enlargement of the gallbladder, thickening of the gallbladder wall, presence of pericholecystic fluid, and tenderness elicited by the ultrasound probe over the gallbladder (sonographic Murphy sign).

Scintigraphy as a second test

Acute cholecystitis is primarily a clinical diagnosis and typically does not require additional imaging beyond ultrasonography. When there is discordance between clinical and ultrasonographic findings, the most accurate second imaging test is scintigraphy of the biliary tract, usually performed with technetium-labeled hydroxy iminodiacetic acid. Given intravenously, the radionuclide is rapidly taken up by the liver and then secreted into the bile. In acute cholecystitis, the cystic duct is functionally occluded and the isotope does not enter the gallbladder, creating an imaging void compared with a normal appearance.

Scintigraphy is more sensitive than abdominal ultrasonography, with a sensitivity of up to 97% vs 81% to 88%, respectively.^29,30 The tests have about equal specificity.

Even though scintigraphy is more sensitive, abdominal ultrasonography is often the initial test for patients with suspected acute cholecystitis because it is more widely available, takes less time, does not involve radiation exposure, and can assess for the presence or absence of gallstones and dilation of the intra- and extrahepatic bile ducts.

Looking for stones in the common bile duct

When acute cholangitis due to choledocholithiasis is suspected, abdominal ultrasonography is a prudent initial test to look for gallstones or biliary dilation suggesting obstruction by stones in the common bile duct. Abdominal ultrasonography has only a 22% to 55% sensitivity for visualizing stones in the common bile duct, but it has a 77% to 87% sensitivity for detecting common bile duct dilation, a surrogate marker of stones.³¹

The normal bile duct diameter ranges from 3 to 6 mm, although mild dilation is often seen in older patients or after cholecystectomy or Roux-en-Y gastric bypass surgery.^32,33 Bile duct dilation of up to 10 mm can be considered normal in patients after cholecystectomy.³⁴ A normal-appearing bile duct on ultrasonography has a negative predictive value of 95% for excluding common bile duct stones.³¹

Endoscopic ultrasonography (EUS), magnetic resonance cholangiopancreatography (MRCP), and endoscopic retrograde cholangiopancreatography (ERCP) have similar sensitivity (89%–94%, 85%–92%, and 89%–93%, respectively) and specificity (94%–95%, 93%–97%, and 100%, respectively) for detecting common bile duct stones.^35–37 EUS is superior to MRCP in detecting stones smaller than 6 mm.³⁸

ERCP should be reserved for managing rather than diagnosing common bile duct stones because of the risk of pancreatitis and perforation. Patients undergoing cholecystectomy who are suspected of having choledocholithiasis may undergo intraoperative cholangiography or laparoscopic common bile duct ultrasonography.

WATCH AND WAIT, OR INTERVENE?

Asymptomatic gallstones

Standard treatment for these patients is expectant management. Cholecystectomy is not recommended for patients with asymptomatic gallstones.⁴⁷ Nevertheless, some patients may benefit from prophylactic cholecystectomy. We and others⁴⁸ suggest considering cholecystectomy in the following patients.

Patients with chronic hemolytic anemia (including children with sickle cell anemia and spherocytosis). These patients have a higher risk of developing calcium bilirubinate stones, and cholecystectomy has improved outcomes.⁴⁹ It should be noted that most of these data come from pediatric populations and have been extrapolated to adults.

Native Americans, who have a higher risk of gallbladder cancer if they have gallstones.^2,50

Conversely, calcification of the gallbladder wall (“porcelain gallbladder”) is no longer considered an absolute indication for cholecystectomy. This condition was thought to be associated with a high rate of gallbladder carcinoma, but analyses of larger, more recent data sets found much smaller risks.^51,52 Further, cholecystectomy in these patients was found to be associated with high rates of postoperative complications. Thus, prophylactic cholecystectomy is no longer recommended in asymptomatic cases of porcelain gallbladder.

In addition, concomitant cholecystectomy in patients undergoing bariatric surgery is no longer considered the therapeutic standard. Historically, cholecystectomy was performed in these patients because of the increased risk of gallstones associated with rapid weight loss after surgery. However, research now weighs against concomitant cholecystectomy with bariatric surgery and most other abdominal surgeries for asymptomatic gallstones.⁵³

Based on information in reference 48.

For patients experiencing acute cholecystitis, laparoscopic cholecystectomy within 72 hours is recommended.⁴⁸ There were safety concerns regarding higher rates of morbidity and conversion from laparoscopic to open cholecystectomy in patients who underwent surgery before the acute cholecystitis episode had settled. However, a large meta-analysis found no significant difference between early and delayed laparoscopic cholecystectomy in bile duct injury or conversion rates.⁵⁴ Further, early cholecystectomy—defined as within 1 week of symptom onset—has been found to reduce gallstone-related complications, shorten hospital stays, and lower costs.^55–57 If the patient cannot undergo surgery, percutaneous cholecystotomy or novel endoscopic gallbladder drainage interventions can be used.

Reprinted from ASGE Standards of Practice Committee; Maple JT, Ben-Menachem T, Anderson MA, et al. The role of endoscopy in the evaluation of suspected choledocholithiasis. Gastrointest Endoscp 2010; 71:1–9 with permission from Elsevier.

Several variables predict the presence of bile duct stones in patients who have symptoms (Table 4). Based on these predictors, the ASGE classifies the probabilities as low (< 10%), intermediate (10% to 50%), and high (> 50%)³¹:

• 
  Low-risk patients require no further evaluation of the common bile duct
• High-risk patients should undergo preoperative ERCP and stone extraction if needed
• Intermediate-risk patients should undergo preoperative imaging with EUS or MRCP or intraoperative bile duct evaluation, depending on the availability, costs, and local expertise.

Patients with associated cholangitis should be given intravenous fluids and broad-spectrum antibiotics. Biliary decompression should be done as early as possible to decrease the risk of morbidity and mortality. For acute cholangitis, ERCP is the treatment of choice.²⁵

Patients with acute gallstone pancreatitis should receive conservative management with intravenous isotonic solutions and pain control, followed by laparoscopic cholecystectomy.⁴⁸

The timing of laparoscopic cholecystectomy in acute gallstone pancreatitis has been debated. Studies conducted during the era of open cholecystectomy reported similar or worse outcomes if cholecystectomy was done sooner rather than later.

However, in 1999, Uhl et al⁵⁸ reported that 48 of 77 patients admitted with acute gallstone pancreatitis were able to undergo laparoscopic cholecystectomy during the same admission. Success rates were 85% (30 of 35 patients) in those with mild disease and 62% (8 of 13 patients) in those with severe disease. They concluded laparoscopic cholecystectomy could be safely performed within 7 days in patients with mild disease, whereas in severe disease at least 3 weeks should elapse because of the risk of infection.

In a randomized trial published in 2010, Aboulian et al⁵⁹ reported that hospital length of stay (the primary end point) was shorter in 25 patients who underwent laparoscopic cholecystectomy early (within 48 hours of admission) than in 25 patients who underwent surgery after abdominal pain had resolved and laboratory enzymes showed a normalizing trend, 3.5 vs 5.8 days (P = .0016). Rates of perioperative complications and need for conversion to open surgery were similar between the 2 groups.

If there is associated cholangitis, patients should also be given broad-spectrum antibiotics and should undergo ERCP within 24 hours of admission.^25–27

SUMMARY

Gallstones are common in US adults. Abdominal ultrasonography is the diagnostic imaging test of choice to detect gallbladder stones and assess for findings suggestive of acute cholecystitis and dilation of the common bile duct. Fortunately, most gallstones are asymptomatic and can usually be managed expectantly. In patients who have symptoms or have gallstone complications, laparoscopic cholecystectomy is the standard of care.

Yes. Sepsis, stroke, chronic kidney disease, pulmonary disease, chemotherapy, heart failure, and stress cardiomyopathy can all raise serum troponin concentrations, and in some cases the elevations are prognostically important. Careful clinical assessment, serial monitoring of troponin levels, and other supportive tests are usually necessary to tell whether troponin elevations are due to acute coronary syndrome or to these other causes.

NOT ONLY A MARKER OF MYOCARDIAL DAMAGE

Troponin, an intracellular protein found in skeletal and cardiac muscle cells, is essential for muscle contraction. Troponin T and troponin I are clinically equivalent, and both are biomarkers of myocardial damage.

A troponin assay is ordered when patients present with sudden onset of symptoms of acute coronary syndrome such as chest pain, dyspnea, diaphoresis, and electrocardiographic abnormalities. The assay is positive when the manufacturer-specified threshold corresponding to a concentration above the 99th percentile is detected.

Serial testing of serum biomarkers of acute myocardial damage is essential to confirm the diagnosis of myocardial infarction. Because of their higher sensitivity and specificity compared with creatine kinase-MB and other markers, troponins are the preferred biomarker in diagnosing acute coronary syndrome.

In 1984, Piper et al¹ reported that free cytosolic pools of cardiac enzymes could be released after reversible myocardial injury as a result of temporary disruption of the cell membrane. This upended the previous assumption that troponin was released only after irreversible myocardial necrosis, and it provided an explanation for troponin elevations observed in conditions with no evidence of epicardial coronary artery disease or permanent myocardial damage.¹

SEPSIS

Studies of patients with sepsis, severe sepsis, and septic shock have shown troponin elevations with no evidence of acute coronary syndrome.² In sepsis, troponin elevations are presumed to be caused by a combination of events. Renal dysfunction leads to decreased clearance of troponin fragments by the kidneys. The massive inflammatory response in septic shock results in cytokine-induced cardiac damage, and increased levels of endogen­ous and exogenous catecholamines damage cardiac myocytes.³

Studies of the prognostic value of these elevations have produced mixed and contradictory results. But a 2013 meta-analysis⁴ showed that patients with a troponin elevation at the time of diagnosis of sepsis had a risk of death almost twice that of patients without a troponin elevation (relative risk 1.91, 95% confidence interval [CI] 1.63–2.24).

STROKE

Acute ischemic stroke can trigger troponin elevations in several ways. Since the risk factors for acute ischemic stroke and coronary stenosis are similar, patients who have an ischemic stroke have a higher risk of coronary atherosclerosis and coronary stenosis than the general population.⁵

Stroke can cause a variety of cardiovascular and respiratory responses (eg, tachyarrhythmia, hypertensive crisis, respiratory failure) that increase the stress on the myocardium. In patients with stroke and concurrent coronary artery stenosis, the increased metabolic demand can exceed the oxygen supply capacity, resulting in myocardial ischemia, which can manifest as increased levels of serum troponin.⁵

Stroke can also cause troponin elevation through neurogenic myocardial damage. Ischemic stroke and intracranial hemorrhage can trigger alterations in autonomic control. Sometimes this results in increased sympathetic activity with concomitant catecholamine surge, leading to contraction band necrosis and other forms of myocardial damage and, as a result, troponin elevation.^5,6 This may explain troponin elevation in patients with acute ischemic stroke in the absence of concomitant coronary artery disease. Recent evidence suggests that patients with acute ischemic stroke and elevated troponin had significantly less angiographic evidence of coronary artery disease than matched patients with non-ST-elevation myocardial infarction.⁷

Cardiac troponins may be elevated in chronic kidney disease. Explanations for this include the theory that troponin is broken down into fragments that are cleared by the kidney.⁸ Therefore, decreased renal function leads to an increase in troponin fragments measured with troponin assays. Other explanations are chronic volume overload, chronic elevation of proinflammatory cytokines, and associated comorbidities such as hypertension.

Troponin elevations can have prognostic significance in chronic kidney disease. In a meta-analysis of 98 studies of patients with chronic kidney disease and no symptoms of acute coronary syndrome, troponin elevation was associated with 2- to 4-fold higher rates of all-cause mortality, cardiovascular mortality, and major acute coronary events in both dialysis-dependent and nondialysis patients.⁸ Thus, troponin is a unique factor in risk-stratification in patients with chronic kidney disease and could affect how it is managed in the future.

To determine if an acute coronary syndrome is taking place when evaluating patients with chronic kidney disease and elevated troponins, physicians must use other evidence—for example, serial measurements of troponin levels showing continued troponin elevation, elevations in troponin from the patient’s baseline, elevated creatine kinase-MB levels, electrocardiographic changes, and clinical symptoms.

PULMONARY DISEASE

Troponin elevation can signify right heart strain in a variety of pulmonary diseases.

Pulmonary embolism. Troponin elevation is a marker of right ventricular dysfunction in patients with moderate to large pulmonary embolism.

In a study of normotensive patients with acute pulmonary embolism, 52% had elevated serum troponin, and they had a higher risk of an adverse outcome (death, recurrent pulmonary embolism, or major bleeding) within 30 days (odds ratio 4.97, 95% CI 1.71–14.43) and a lower probability of 6-month survival.⁹ Troponin elevation in pulmonary embolism is not helpful in confirming the diagnosis but is primarily useful in prognosis.

Pulmonary arterial hypertension. Cardiac troponin elevations can also indicate severe disease and poor outcomes in patients with pulmonary arterial hypertension. A study by Heresi et al¹⁰ confirmed this, even in patients with only slight elevations in troponin levels. Troponin was detected in 17 (25%) of 68 patients with pulmonary arterial hypertension diagnostic category 1. Further, patients with detectable troponin had more advanced functional class symptoms, a shorter 6-minute walk distance, more pericardial effusions, larger right atrial area, and higher B-type natriuretic peptide and C-reactive protein levels.¹⁰

Measuring troponins in the setting of pulmonary hypertension allows clinicians to identify high-risk patients and may help guide the management of these patients.

Chronic obstructive pulmonary disease. Elevation of serum troponins is also reported in patients with acute exacerbation of chronic obstructive pulmonary disease and has been correlated with increased all-cause mortality rates in these patients.¹¹

CHEMOTHERAPY

Chemotherapy-induced cardiotoxicity may result in troponin elevations. Chemotherapy causes cardiac toxicity by several mechanisms, including production of oxygen free radicals, disturbance of mitochondrial energy metabolism, intracellular calcium overload, and increased lipid peroxidation. Chemotherapeutic agents associated with cardiotoxicity include anthracyclines, trastuzumab, chlormethine, and mitomycin.

Chemotherapy-induced left ventricular deterioration is often irreversible. Monitoring troponin levels can help identify problems before cardiac dysfunction becomes clinically evident during the weeks and months after the start of high-dose chemotherapy.

Cardinale et al¹² found marked myocardial depression 7 months after the start of high-dose chemotherapy. They reported a close relationship between short-term troponin elevation and the greatest reduction in left-ventricular ejection fraction (r = −0.87; P < .0001). Normal troponin values after high-dose chemotherapy also seemed to identify patients at lower risk, with either no cardiac damage or only transient subclinical left-ventricular dysfunction.¹²

HEART FAILURE

Heart failure leads to release of cardiac troponins through myocardial strain and myocardial death. Volume and pressure overload of the ventricles causes excessive wall tension, resulting in myofibrillar damage. Measuring troponins is an effective way to detect cardiac myolysis in heart failure, independent of the presence of coronary artery disease.

In heart failure, elevated troponins correlate with adverse outcome in both hospitalized and stable patients. In addition, elevation of both troponins and B-type natriuretic peptide is associated with worse heart failure outcomes than elevation of either marker alone.

A prospective study¹³ of patients with New York Heart Association class III or IV heart failure showed that an increase in troponin concentration from normal baseline was associated with a risk of death, cardiac transplant, or hospitalization that was 3.4 to 5.09 times higher. Further elevations in B-type natriuretic peptide during the study period were associated with a poor outcome (hazard ratio 5.09; P < .001). Combined elevations of troponin and B-type natriuretic peptide defined the group at highest risk (hazard ratio 8.58; P < .001).

Increased myocardial wall stress may lead to decreased subendocardial perfusion, with resulting troponin elevation and decline in left ventricular systolic function. Further, in vitro experiments with myocytes established a link between myocardial wall stretch and programmed cell death, which may contribute to troponin elevations.¹⁴

Profound reversible myocardial depression and troponin elevation are seen after sudden emotional stress, a condition called stress-induced or takotsubo cardiomyopathy. While the exact mechanism of stress-induced cardiomyopathy remains unclear, it is thought to be due to sudden supraphysiologic elevation of catecholamines and related neuropeptides. Although vasospasm in the epicardial and microvascular circulation has been suggested as the possible mechanism of left ventricular systolic dysfunction and troponin elevation, cardiac myocyte injury from catecholamine- induced cyclic AMP-mediated calcium overload and oxygen-derived free radicals appears to be a more likely mechanism.¹⁵

PSEUDOELEVATIONS OF TROPONIN

In rare cases, endogenous antibodies (eg, heterophilic antibodies) in the blood specimen can interfere with the processing of the troponin immunoassay in the laboratory, causing a false-positive assay. This can occur with samples from patients with a viral infection or autoimmune condition as well as with samples from patients treated with intravenous immunoglobulin (Ig). Heterophilic antibodies can bind to the Fc region of the test antibodies in certain troponin assays, leading to false-positive elevations.¹⁶ Macrotroponin, a molecule found in patients with autoantibodies against troponin I, is composed of troponin I fragments and IgG antibodies and can also cause a false-positive troponin immunoassay.¹⁶

In patients with seropositive rheumatoid arthritis, a false-positive troponin I assay was associated with a high concentration of IgM rheumatoid factor with the use of certain immunoassay techniques.¹⁷ In patients with acute skeletal muscle injury, the first-generation troponin T assay was found to be falsely positive due to the nonspecific binding of skeletal muscle troponin T to the walls of the test tube used for the assay. When the second-generation troponin T assay was used, troponin T levels were found to be slightly more positive than troponin I levels (1.7 vs 1.5 times the upper limit of normal), especially in patients with renal failure.¹⁸

Troponin may also be falsely elevated in hemolyzed blood samples. This has to be taken into consideration in interpreting the results of troponin testing in severely hemolyzed blood samples. However, Puelacher et al¹⁹ suggested that the presence of hemolysis did not appear to interfere with clinical value of the test.

Yes. Sepsis, stroke, chronic kidney disease, pulmonary disease, chemotherapy, heart failure, and stress cardiomyopathy can all raise serum troponin concentrations, and in some cases the elevations are prognostically important. Careful clinical assessment, serial monitoring of troponin levels, and other supportive tests are usually necessary to tell whether troponin elevations are due to acute coronary syndrome or to these other causes.

NOT ONLY A MARKER OF MYOCARDIAL DAMAGE

Troponin, an intracellular protein found in skeletal and cardiac muscle cells, is essential for muscle contraction. Troponin T and troponin I are clinically equivalent, and both are biomarkers of myocardial damage.

A troponin assay is ordered when patients present with sudden onset of symptoms of acute coronary syndrome such as chest pain, dyspnea, diaphoresis, and electrocardiographic abnormalities. The assay is positive when the manufacturer-specified threshold corresponding to a concentration above the 99th percentile is detected.

Serial testing of serum biomarkers of acute myocardial damage is essential to confirm the diagnosis of myocardial infarction. Because of their higher sensitivity and specificity compared with creatine kinase-MB and other markers, troponins are the preferred biomarker in diagnosing acute coronary syndrome.

In 1984, Piper et al¹ reported that free cytosolic pools of cardiac enzymes could be released after reversible myocardial injury as a result of temporary disruption of the cell membrane. This upended the previous assumption that troponin was released only after irreversible myocardial necrosis, and it provided an explanation for troponin elevations observed in conditions with no evidence of epicardial coronary artery disease or permanent myocardial damage.¹

SEPSIS

Studies of patients with sepsis, severe sepsis, and septic shock have shown troponin elevations with no evidence of acute coronary syndrome.² In sepsis, troponin elevations are presumed to be caused by a combination of events. Renal dysfunction leads to decreased clearance of troponin fragments by the kidneys. The massive inflammatory response in septic shock results in cytokine-induced cardiac damage, and increased levels of endogen­ous and exogenous catecholamines damage cardiac myocytes.³

Studies of the prognostic value of these elevations have produced mixed and contradictory results. But a 2013 meta-analysis⁴ showed that patients with a troponin elevation at the time of diagnosis of sepsis had a risk of death almost twice that of patients without a troponin elevation (relative risk 1.91, 95% confidence interval [CI] 1.63–2.24).

STROKE

Acute ischemic stroke can trigger troponin elevations in several ways. Since the risk factors for acute ischemic stroke and coronary stenosis are similar, patients who have an ischemic stroke have a higher risk of coronary atherosclerosis and coronary stenosis than the general population.⁵

Stroke can cause a variety of cardiovascular and respiratory responses (eg, tachyarrhythmia, hypertensive crisis, respiratory failure) that increase the stress on the myocardium. In patients with stroke and concurrent coronary artery stenosis, the increased metabolic demand can exceed the oxygen supply capacity, resulting in myocardial ischemia, which can manifest as increased levels of serum troponin.⁵

Stroke can also cause troponin elevation through neurogenic myocardial damage. Ischemic stroke and intracranial hemorrhage can trigger alterations in autonomic control. Sometimes this results in increased sympathetic activity with concomitant catecholamine surge, leading to contraction band necrosis and other forms of myocardial damage and, as a result, troponin elevation.^5,6 This may explain troponin elevation in patients with acute ischemic stroke in the absence of concomitant coronary artery disease. Recent evidence suggests that patients with acute ischemic stroke and elevated troponin had significantly less angiographic evidence of coronary artery disease than matched patients with non-ST-elevation myocardial infarction.⁷

Cardiac troponins may be elevated in chronic kidney disease. Explanations for this include the theory that troponin is broken down into fragments that are cleared by the kidney.⁸ Therefore, decreased renal function leads to an increase in troponin fragments measured with troponin assays. Other explanations are chronic volume overload, chronic elevation of proinflammatory cytokines, and associated comorbidities such as hypertension.

Troponin elevations can have prognostic significance in chronic kidney disease. In a meta-analysis of 98 studies of patients with chronic kidney disease and no symptoms of acute coronary syndrome, troponin elevation was associated with 2- to 4-fold higher rates of all-cause mortality, cardiovascular mortality, and major acute coronary events in both dialysis-dependent and nondialysis patients.⁸ Thus, troponin is a unique factor in risk-stratification in patients with chronic kidney disease and could affect how it is managed in the future.

To determine if an acute coronary syndrome is taking place when evaluating patients with chronic kidney disease and elevated troponins, physicians must use other evidence—for example, serial measurements of troponin levels showing continued troponin elevation, elevations in troponin from the patient’s baseline, elevated creatine kinase-MB levels, electrocardiographic changes, and clinical symptoms.

PULMONARY DISEASE

Troponin elevation can signify right heart strain in a variety of pulmonary diseases.

Pulmonary embolism. Troponin elevation is a marker of right ventricular dysfunction in patients with moderate to large pulmonary embolism.

In a study of normotensive patients with acute pulmonary embolism, 52% had elevated serum troponin, and they had a higher risk of an adverse outcome (death, recurrent pulmonary embolism, or major bleeding) within 30 days (odds ratio 4.97, 95% CI 1.71–14.43) and a lower probability of 6-month survival.⁹ Troponin elevation in pulmonary embolism is not helpful in confirming the diagnosis but is primarily useful in prognosis.

Pulmonary arterial hypertension. Cardiac troponin elevations can also indicate severe disease and poor outcomes in patients with pulmonary arterial hypertension. A study by Heresi et al¹⁰ confirmed this, even in patients with only slight elevations in troponin levels. Troponin was detected in 17 (25%) of 68 patients with pulmonary arterial hypertension diagnostic category 1. Further, patients with detectable troponin had more advanced functional class symptoms, a shorter 6-minute walk distance, more pericardial effusions, larger right atrial area, and higher B-type natriuretic peptide and C-reactive protein levels.¹⁰

Measuring troponins in the setting of pulmonary hypertension allows clinicians to identify high-risk patients and may help guide the management of these patients.

Chronic obstructive pulmonary disease. Elevation of serum troponins is also reported in patients with acute exacerbation of chronic obstructive pulmonary disease and has been correlated with increased all-cause mortality rates in these patients.¹¹

CHEMOTHERAPY

Chemotherapy-induced cardiotoxicity may result in troponin elevations. Chemotherapy causes cardiac toxicity by several mechanisms, including production of oxygen free radicals, disturbance of mitochondrial energy metabolism, intracellular calcium overload, and increased lipid peroxidation. Chemotherapeutic agents associated with cardiotoxicity include anthracyclines, trastuzumab, chlormethine, and mitomycin.

Chemotherapy-induced left ventricular deterioration is often irreversible. Monitoring troponin levels can help identify problems before cardiac dysfunction becomes clinically evident during the weeks and months after the start of high-dose chemotherapy.

Cardinale et al¹² found marked myocardial depression 7 months after the start of high-dose chemotherapy. They reported a close relationship between short-term troponin elevation and the greatest reduction in left-ventricular ejection fraction (r = −0.87; P < .0001). Normal troponin values after high-dose chemotherapy also seemed to identify patients at lower risk, with either no cardiac damage or only transient subclinical left-ventricular dysfunction.¹²

HEART FAILURE

Heart failure leads to release of cardiac troponins through myocardial strain and myocardial death. Volume and pressure overload of the ventricles causes excessive wall tension, resulting in myofibrillar damage. Measuring troponins is an effective way to detect cardiac myolysis in heart failure, independent of the presence of coronary artery disease.

In heart failure, elevated troponins correlate with adverse outcome in both hospitalized and stable patients. In addition, elevation of both troponins and B-type natriuretic peptide is associated with worse heart failure outcomes than elevation of either marker alone.

A prospective study¹³ of patients with New York Heart Association class III or IV heart failure showed that an increase in troponin concentration from normal baseline was associated with a risk of death, cardiac transplant, or hospitalization that was 3.4 to 5.09 times higher. Further elevations in B-type natriuretic peptide during the study period were associated with a poor outcome (hazard ratio 5.09; P < .001). Combined elevations of troponin and B-type natriuretic peptide defined the group at highest risk (hazard ratio 8.58; P < .001).

Increased myocardial wall stress may lead to decreased subendocardial perfusion, with resulting troponin elevation and decline in left ventricular systolic function. Further, in vitro experiments with myocytes established a link between myocardial wall stretch and programmed cell death, which may contribute to troponin elevations.¹⁴

Profound reversible myocardial depression and troponin elevation are seen after sudden emotional stress, a condition called stress-induced or takotsubo cardiomyopathy. While the exact mechanism of stress-induced cardiomyopathy remains unclear, it is thought to be due to sudden supraphysiologic elevation of catecholamines and related neuropeptides. Although vasospasm in the epicardial and microvascular circulation has been suggested as the possible mechanism of left ventricular systolic dysfunction and troponin elevation, cardiac myocyte injury from catecholamine- induced cyclic AMP-mediated calcium overload and oxygen-derived free radicals appears to be a more likely mechanism.¹⁵

PSEUDOELEVATIONS OF TROPONIN

In rare cases, endogenous antibodies (eg, heterophilic antibodies) in the blood specimen can interfere with the processing of the troponin immunoassay in the laboratory, causing a false-positive assay. This can occur with samples from patients with a viral infection or autoimmune condition as well as with samples from patients treated with intravenous immunoglobulin (Ig). Heterophilic antibodies can bind to the Fc region of the test antibodies in certain troponin assays, leading to false-positive elevations.¹⁶ Macrotroponin, a molecule found in patients with autoantibodies against troponin I, is composed of troponin I fragments and IgG antibodies and can also cause a false-positive troponin immunoassay.¹⁶

In patients with seropositive rheumatoid arthritis, a false-positive troponin I assay was associated with a high concentration of IgM rheumatoid factor with the use of certain immunoassay techniques.¹⁷ In patients with acute skeletal muscle injury, the first-generation troponin T assay was found to be falsely positive due to the nonspecific binding of skeletal muscle troponin T to the walls of the test tube used for the assay. When the second-generation troponin T assay was used, troponin T levels were found to be slightly more positive than troponin I levels (1.7 vs 1.5 times the upper limit of normal), especially in patients with renal failure.¹⁸

Troponin may also be falsely elevated in hemolyzed blood samples. This has to be taken into consideration in interpreting the results of troponin testing in severely hemolyzed blood samples. However, Puelacher et al¹⁹ suggested that the presence of hemolysis did not appear to interfere with clinical value of the test.

Yes. Sepsis, stroke, chronic kidney disease, pulmonary disease, chemotherapy, heart failure, and stress cardiomyopathy can all raise serum troponin concentrations, and in some cases the elevations are prognostically important. Careful clinical assessment, serial monitoring of troponin levels, and other supportive tests are usually necessary to tell whether troponin elevations are due to acute coronary syndrome or to these other causes.

NOT ONLY A MARKER OF MYOCARDIAL DAMAGE

Troponin, an intracellular protein found in skeletal and cardiac muscle cells, is essential for muscle contraction. Troponin T and troponin I are clinically equivalent, and both are biomarkers of myocardial damage.

A troponin assay is ordered when patients present with sudden onset of symptoms of acute coronary syndrome such as chest pain, dyspnea, diaphoresis, and electrocardiographic abnormalities. The assay is positive when the manufacturer-specified threshold corresponding to a concentration above the 99th percentile is detected.

Serial testing of serum biomarkers of acute myocardial damage is essential to confirm the diagnosis of myocardial infarction. Because of their higher sensitivity and specificity compared with creatine kinase-MB and other markers, troponins are the preferred biomarker in diagnosing acute coronary syndrome.

In 1984, Piper et al¹ reported that free cytosolic pools of cardiac enzymes could be released after reversible myocardial injury as a result of temporary disruption of the cell membrane. This upended the previous assumption that troponin was released only after irreversible myocardial necrosis, and it provided an explanation for troponin elevations observed in conditions with no evidence of epicardial coronary artery disease or permanent myocardial damage.¹

SEPSIS

Studies of patients with sepsis, severe sepsis, and septic shock have shown troponin elevations with no evidence of acute coronary syndrome.² In sepsis, troponin elevations are presumed to be caused by a combination of events. Renal dysfunction leads to decreased clearance of troponin fragments by the kidneys. The massive inflammatory response in septic shock results in cytokine-induced cardiac damage, and increased levels of endogen­ous and exogenous catecholamines damage cardiac myocytes.³

Studies of the prognostic value of these elevations have produced mixed and contradictory results. But a 2013 meta-analysis⁴ showed that patients with a troponin elevation at the time of diagnosis of sepsis had a risk of death almost twice that of patients without a troponin elevation (relative risk 1.91, 95% confidence interval [CI] 1.63–2.24).

STROKE

Acute ischemic stroke can trigger troponin elevations in several ways. Since the risk factors for acute ischemic stroke and coronary stenosis are similar, patients who have an ischemic stroke have a higher risk of coronary atherosclerosis and coronary stenosis than the general population.⁵

Stroke can cause a variety of cardiovascular and respiratory responses (eg, tachyarrhythmia, hypertensive crisis, respiratory failure) that increase the stress on the myocardium. In patients with stroke and concurrent coronary artery stenosis, the increased metabolic demand can exceed the oxygen supply capacity, resulting in myocardial ischemia, which can manifest as increased levels of serum troponin.⁵

Stroke can also cause troponin elevation through neurogenic myocardial damage. Ischemic stroke and intracranial hemorrhage can trigger alterations in autonomic control. Sometimes this results in increased sympathetic activity with concomitant catecholamine surge, leading to contraction band necrosis and other forms of myocardial damage and, as a result, troponin elevation.^5,6 This may explain troponin elevation in patients with acute ischemic stroke in the absence of concomitant coronary artery disease. Recent evidence suggests that patients with acute ischemic stroke and elevated troponin had significantly less angiographic evidence of coronary artery disease than matched patients with non-ST-elevation myocardial infarction.⁷

Cardiac troponins may be elevated in chronic kidney disease. Explanations for this include the theory that troponin is broken down into fragments that are cleared by the kidney.⁸ Therefore, decreased renal function leads to an increase in troponin fragments measured with troponin assays. Other explanations are chronic volume overload, chronic elevation of proinflammatory cytokines, and associated comorbidities such as hypertension.

Troponin elevations can have prognostic significance in chronic kidney disease. In a meta-analysis of 98 studies of patients with chronic kidney disease and no symptoms of acute coronary syndrome, troponin elevation was associated with 2- to 4-fold higher rates of all-cause mortality, cardiovascular mortality, and major acute coronary events in both dialysis-dependent and nondialysis patients.⁸ Thus, troponin is a unique factor in risk-stratification in patients with chronic kidney disease and could affect how it is managed in the future.

To determine if an acute coronary syndrome is taking place when evaluating patients with chronic kidney disease and elevated troponins, physicians must use other evidence—for example, serial measurements of troponin levels showing continued troponin elevation, elevations in troponin from the patient’s baseline, elevated creatine kinase-MB levels, electrocardiographic changes, and clinical symptoms.

PULMONARY DISEASE

Troponin elevation can signify right heart strain in a variety of pulmonary diseases.

Pulmonary embolism. Troponin elevation is a marker of right ventricular dysfunction in patients with moderate to large pulmonary embolism.

In a study of normotensive patients with acute pulmonary embolism, 52% had elevated serum troponin, and they had a higher risk of an adverse outcome (death, recurrent pulmonary embolism, or major bleeding) within 30 days (odds ratio 4.97, 95% CI 1.71–14.43) and a lower probability of 6-month survival.⁹ Troponin elevation in pulmonary embolism is not helpful in confirming the diagnosis but is primarily useful in prognosis.

Pulmonary arterial hypertension. Cardiac troponin elevations can also indicate severe disease and poor outcomes in patients with pulmonary arterial hypertension. A study by Heresi et al¹⁰ confirmed this, even in patients with only slight elevations in troponin levels. Troponin was detected in 17 (25%) of 68 patients with pulmonary arterial hypertension diagnostic category 1. Further, patients with detectable troponin had more advanced functional class symptoms, a shorter 6-minute walk distance, more pericardial effusions, larger right atrial area, and higher B-type natriuretic peptide and C-reactive protein levels.¹⁰

Measuring troponins in the setting of pulmonary hypertension allows clinicians to identify high-risk patients and may help guide the management of these patients.

Chronic obstructive pulmonary disease. Elevation of serum troponins is also reported in patients with acute exacerbation of chronic obstructive pulmonary disease and has been correlated with increased all-cause mortality rates in these patients.¹¹

CHEMOTHERAPY

Chemotherapy-induced cardiotoxicity may result in troponin elevations. Chemotherapy causes cardiac toxicity by several mechanisms, including production of oxygen free radicals, disturbance of mitochondrial energy metabolism, intracellular calcium overload, and increased lipid peroxidation. Chemotherapeutic agents associated with cardiotoxicity include anthracyclines, trastuzumab, chlormethine, and mitomycin.

Chemotherapy-induced left ventricular deterioration is often irreversible. Monitoring troponin levels can help identify problems before cardiac dysfunction becomes clinically evident during the weeks and months after the start of high-dose chemotherapy.

Cardinale et al¹² found marked myocardial depression 7 months after the start of high-dose chemotherapy. They reported a close relationship between short-term troponin elevation and the greatest reduction in left-ventricular ejection fraction (r = −0.87; P < .0001). Normal troponin values after high-dose chemotherapy also seemed to identify patients at lower risk, with either no cardiac damage or only transient subclinical left-ventricular dysfunction.¹²

HEART FAILURE

Heart failure leads to release of cardiac troponins through myocardial strain and myocardial death. Volume and pressure overload of the ventricles causes excessive wall tension, resulting in myofibrillar damage. Measuring troponins is an effective way to detect cardiac myolysis in heart failure, independent of the presence of coronary artery disease.

In heart failure, elevated troponins correlate with adverse outcome in both hospitalized and stable patients. In addition, elevation of both troponins and B-type natriuretic peptide is associated with worse heart failure outcomes than elevation of either marker alone.

A prospective study¹³ of patients with New York Heart Association class III or IV heart failure showed that an increase in troponin concentration from normal baseline was associated with a risk of death, cardiac transplant, or hospitalization that was 3.4 to 5.09 times higher. Further elevations in B-type natriuretic peptide during the study period were associated with a poor outcome (hazard ratio 5.09; P < .001). Combined elevations of troponin and B-type natriuretic peptide defined the group at highest risk (hazard ratio 8.58; P < .001).

Increased myocardial wall stress may lead to decreased subendocardial perfusion, with resulting troponin elevation and decline in left ventricular systolic function. Further, in vitro experiments with myocytes established a link between myocardial wall stretch and programmed cell death, which may contribute to troponin elevations.¹⁴

Profound reversible myocardial depression and troponin elevation are seen after sudden emotional stress, a condition called stress-induced or takotsubo cardiomyopathy. While the exact mechanism of stress-induced cardiomyopathy remains unclear, it is thought to be due to sudden supraphysiologic elevation of catecholamines and related neuropeptides. Although vasospasm in the epicardial and microvascular circulation has been suggested as the possible mechanism of left ventricular systolic dysfunction and troponin elevation, cardiac myocyte injury from catecholamine- induced cyclic AMP-mediated calcium overload and oxygen-derived free radicals appears to be a more likely mechanism.¹⁵

PSEUDOELEVATIONS OF TROPONIN

In rare cases, endogenous antibodies (eg, heterophilic antibodies) in the blood specimen can interfere with the processing of the troponin immunoassay in the laboratory, causing a false-positive assay. This can occur with samples from patients with a viral infection or autoimmune condition as well as with samples from patients treated with intravenous immunoglobulin (Ig). Heterophilic antibodies can bind to the Fc region of the test antibodies in certain troponin assays, leading to false-positive elevations.¹⁶ Macrotroponin, a molecule found in patients with autoantibodies against troponin I, is composed of troponin I fragments and IgG antibodies and can also cause a false-positive troponin immunoassay.¹⁶

In patients with seropositive rheumatoid arthritis, a false-positive troponin I assay was associated with a high concentration of IgM rheumatoid factor with the use of certain immunoassay techniques.¹⁷ In patients with acute skeletal muscle injury, the first-generation troponin T assay was found to be falsely positive due to the nonspecific binding of skeletal muscle troponin T to the walls of the test tube used for the assay. When the second-generation troponin T assay was used, troponin T levels were found to be slightly more positive than troponin I levels (1.7 vs 1.5 times the upper limit of normal), especially in patients with renal failure.¹⁸

Troponin may also be falsely elevated in hemolyzed blood samples. This has to be taken into consideration in interpreting the results of troponin testing in severely hemolyzed blood samples. However, Puelacher et al¹⁹ suggested that the presence of hemolysis did not appear to interfere with clinical value of the test.

New laboratory tests seem to go through a life cycle. At first, some are used mainly by subspecialists, who became aware of them through early clinical trials or studies presented at specialty meetings. The general medical community adopts their use after noting that they are being ordered by consultants or were used in important published studies.

Sometimes, a new test is significantly better than the older ones, and clinical pathologists and subspecialists encourage us to use it. Sometimes, a new test may represent a breakthrough in the understanding of the pathophysiology of a disease, and its use is promoted by clinicians with special interest in that disease. Testing for serum troponin, as discussed by Sebastian et al in this issue of the Journal, is an example primarily of the first situation, while testing for antineutrophil cytoplasmic antibodies (ANCA) and immunoglobulin G4 are two of many examples of the second.

Once a test comes into widespread use, its accuracy and reproducibility can be problematic. The assay itself may have inherent weaknesses, or techniques may not be standardized among different laboratories; think about diagnosis of the antiphospholipid antibody syndrome. Standardization of laboratory techniques can often be achieved. For troponin, this remains a problem, though small, for patients whose serum is tested in different laboratories or for clinicians trying to directly compare different clinical trial results; but it doesn’t affect clinical decision-making when longitudinally following a specific patient through a single hospitalization.

In its mature years, as a useful novel test becomes widely used, it may alter how we view the management and pathophysiology of a disease. For example, in the days when postoperative myocardial infarction (MI) was diagnosed by electrocardiographic changes and then by elevations in creatine kinase (CK) and alterations in the ratio of  aspartate aminotransferase (AST) to alanine aminotransferase (ALT), the peak in MI incidence was thought to occur several days after surgery. With the advent of CK isoenzymes and then cardiac myocyte-derived troponin, it became apparent that perioperative myocardial injury occurs more in a time frame of hours after surgery. Laboratory data dovetailed with pathologic and angiographic data indicating that the mechanism of MI in the perioperative setting for many patients is different than in “native” MI. As newer, highly sensitive troponin assays are introduced, they may further our understanding of mechanisms of cardiac myocyte membrane injury and tissue necrosis, and may further clarify (or blur) the distinction between the two.

Often, a widely used test is ordered in clinical situations that were not specifically evaluated during initial studies of the test and early use by specialists. Case reports of unexpected results then appear in the literature. Intrinsic test performance may occasionally be influenced in unanticipated ways (eg, rheumatoid factor can affect test results of some troponin and cryptococcal antigen assays), but more frequently it is the definition of “normal” and interpretation of the test results in specific clinical conditions that are affected. For example, troponin levels are higher in patients with chronic kidney disease and severe sepsis. These elevations may be explained by decreased renal clearance of detected fragments of troponin but may also reflect subclinical myocardial injury related to circulating cytokines or other factors. Elevation of troponins in patients with these and other conditions has correlated with poorer outcomes. Thus, in some settings, elevated circulating troponin has greater prognostic than diagnostic significance.

Recognizing imperfect test specificity (false-positive results) is critical when using a test in complex clinical situations. This can be especially challenging when using indirect serologic tests: consider the many reasons for “false-positive” antinuclear antibody, ANCA, and rheumatoid factor test results. But it can also be a challenge when trying to use a targeted test like troponin to distinguish between MI, sepsis, and pulmonary embolism as the cause of acute hypotension.

Many routinely ordered tests require more nuanced interpretation than simply checking the value against the defined laboratory “normal.” These nuances may be well known to those who order the test often or to specialists, but not to all. Familiarity with tests can also result in a subliminal assumption that we fully understand their characteristics and can lead to misinterpretation of results. There are forgotten critical concepts about tests that are ordered extremely commonly: eg, AST and ALT do not come only from the liver and do not reflect “liver function.” Liver biopsy is unlikely to provide the explanation for a myositis patient’s sense of weakness, even if the aminotransferase levels are elevated in the several-hundred range.

A CALL FOR MANUSCRIPTS

I invite you to draw on your personal experience and the literature and submit short manuscripts that address the nuanced interpretation, limitations, and cost of specific laboratory tests. As with all submissions, these will undergo peer review for content accuracy, as well as relevancy and utility for our core readership before being considered for publication.

New laboratory tests seem to go through a life cycle. At first, some are used mainly by subspecialists, who became aware of them through early clinical trials or studies presented at specialty meetings. The general medical community adopts their use after noting that they are being ordered by consultants or were used in important published studies.

Sometimes, a new test is significantly better than the older ones, and clinical pathologists and subspecialists encourage us to use it. Sometimes, a new test may represent a breakthrough in the understanding of the pathophysiology of a disease, and its use is promoted by clinicians with special interest in that disease. Testing for serum troponin, as discussed by Sebastian et al in this issue of the Journal, is an example primarily of the first situation, while testing for antineutrophil cytoplasmic antibodies (ANCA) and immunoglobulin G4 are two of many examples of the second.

Once a test comes into widespread use, its accuracy and reproducibility can be problematic. The assay itself may have inherent weaknesses, or techniques may not be standardized among different laboratories; think about diagnosis of the antiphospholipid antibody syndrome. Standardization of laboratory techniques can often be achieved. For troponin, this remains a problem, though small, for patients whose serum is tested in different laboratories or for clinicians trying to directly compare different clinical trial results; but it doesn’t affect clinical decision-making when longitudinally following a specific patient through a single hospitalization.

In its mature years, as a useful novel test becomes widely used, it may alter how we view the management and pathophysiology of a disease. For example, in the days when postoperative myocardial infarction (MI) was diagnosed by electrocardiographic changes and then by elevations in creatine kinase (CK) and alterations in the ratio of  aspartate aminotransferase (AST) to alanine aminotransferase (ALT), the peak in MI incidence was thought to occur several days after surgery. With the advent of CK isoenzymes and then cardiac myocyte-derived troponin, it became apparent that perioperative myocardial injury occurs more in a time frame of hours after surgery. Laboratory data dovetailed with pathologic and angiographic data indicating that the mechanism of MI in the perioperative setting for many patients is different than in “native” MI. As newer, highly sensitive troponin assays are introduced, they may further our understanding of mechanisms of cardiac myocyte membrane injury and tissue necrosis, and may further clarify (or blur) the distinction between the two.

Often, a widely used test is ordered in clinical situations that were not specifically evaluated during initial studies of the test and early use by specialists. Case reports of unexpected results then appear in the literature. Intrinsic test performance may occasionally be influenced in unanticipated ways (eg, rheumatoid factor can affect test results of some troponin and cryptococcal antigen assays), but more frequently it is the definition of “normal” and interpretation of the test results in specific clinical conditions that are affected. For example, troponin levels are higher in patients with chronic kidney disease and severe sepsis. These elevations may be explained by decreased renal clearance of detected fragments of troponin but may also reflect subclinical myocardial injury related to circulating cytokines or other factors. Elevation of troponins in patients with these and other conditions has correlated with poorer outcomes. Thus, in some settings, elevated circulating troponin has greater prognostic than diagnostic significance.

Recognizing imperfect test specificity (false-positive results) is critical when using a test in complex clinical situations. This can be especially challenging when using indirect serologic tests: consider the many reasons for “false-positive” antinuclear antibody, ANCA, and rheumatoid factor test results. But it can also be a challenge when trying to use a targeted test like troponin to distinguish between MI, sepsis, and pulmonary embolism as the cause of acute hypotension.

Many routinely ordered tests require more nuanced interpretation than simply checking the value against the defined laboratory “normal.” These nuances may be well known to those who order the test often or to specialists, but not to all. Familiarity with tests can also result in a subliminal assumption that we fully understand their characteristics and can lead to misinterpretation of results. There are forgotten critical concepts about tests that are ordered extremely commonly: eg, AST and ALT do not come only from the liver and do not reflect “liver function.” Liver biopsy is unlikely to provide the explanation for a myositis patient’s sense of weakness, even if the aminotransferase levels are elevated in the several-hundred range.

A CALL FOR MANUSCRIPTS

I invite you to draw on your personal experience and the literature and submit short manuscripts that address the nuanced interpretation, limitations, and cost of specific laboratory tests. As with all submissions, these will undergo peer review for content accuracy, as well as relevancy and utility for our core readership before being considered for publication.

New laboratory tests seem to go through a life cycle. At first, some are used mainly by subspecialists, who became aware of them through early clinical trials or studies presented at specialty meetings. The general medical community adopts their use after noting that they are being ordered by consultants or were used in important published studies.

Sometimes, a new test is significantly better than the older ones, and clinical pathologists and subspecialists encourage us to use it. Sometimes, a new test may represent a breakthrough in the understanding of the pathophysiology of a disease, and its use is promoted by clinicians with special interest in that disease. Testing for serum troponin, as discussed by Sebastian et al in this issue of the Journal, is an example primarily of the first situation, while testing for antineutrophil cytoplasmic antibodies (ANCA) and immunoglobulin G4 are two of many examples of the second.

Once a test comes into widespread use, its accuracy and reproducibility can be problematic. The assay itself may have inherent weaknesses, or techniques may not be standardized among different laboratories; think about diagnosis of the antiphospholipid antibody syndrome. Standardization of laboratory techniques can often be achieved. For troponin, this remains a problem, though small, for patients whose serum is tested in different laboratories or for clinicians trying to directly compare different clinical trial results; but it doesn’t affect clinical decision-making when longitudinally following a specific patient through a single hospitalization.

In its mature years, as a useful novel test becomes widely used, it may alter how we view the management and pathophysiology of a disease. For example, in the days when postoperative myocardial infarction (MI) was diagnosed by electrocardiographic changes and then by elevations in creatine kinase (CK) and alterations in the ratio of  aspartate aminotransferase (AST) to alanine aminotransferase (ALT), the peak in MI incidence was thought to occur several days after surgery. With the advent of CK isoenzymes and then cardiac myocyte-derived troponin, it became apparent that perioperative myocardial injury occurs more in a time frame of hours after surgery. Laboratory data dovetailed with pathologic and angiographic data indicating that the mechanism of MI in the perioperative setting for many patients is different than in “native” MI. As newer, highly sensitive troponin assays are introduced, they may further our understanding of mechanisms of cardiac myocyte membrane injury and tissue necrosis, and may further clarify (or blur) the distinction between the two.

Often, a widely used test is ordered in clinical situations that were not specifically evaluated during initial studies of the test and early use by specialists. Case reports of unexpected results then appear in the literature. Intrinsic test performance may occasionally be influenced in unanticipated ways (eg, rheumatoid factor can affect test results of some troponin and cryptococcal antigen assays), but more frequently it is the definition of “normal” and interpretation of the test results in specific clinical conditions that are affected. For example, troponin levels are higher in patients with chronic kidney disease and severe sepsis. These elevations may be explained by decreased renal clearance of detected fragments of troponin but may also reflect subclinical myocardial injury related to circulating cytokines or other factors. Elevation of troponins in patients with these and other conditions has correlated with poorer outcomes. Thus, in some settings, elevated circulating troponin has greater prognostic than diagnostic significance.

Recognizing imperfect test specificity (false-positive results) is critical when using a test in complex clinical situations. This can be especially challenging when using indirect serologic tests: consider the many reasons for “false-positive” antinuclear antibody, ANCA, and rheumatoid factor test results. But it can also be a challenge when trying to use a targeted test like troponin to distinguish between MI, sepsis, and pulmonary embolism as the cause of acute hypotension.

Many routinely ordered tests require more nuanced interpretation than simply checking the value against the defined laboratory “normal.” These nuances may be well known to those who order the test often or to specialists, but not to all. Familiarity with tests can also result in a subliminal assumption that we fully understand their characteristics and can lead to misinterpretation of results. There are forgotten critical concepts about tests that are ordered extremely commonly: eg, AST and ALT do not come only from the liver and do not reflect “liver function.” Liver biopsy is unlikely to provide the explanation for a myositis patient’s sense of weakness, even if the aminotransferase levels are elevated in the several-hundred range.

A CALL FOR MANUSCRIPTS

I invite you to draw on your personal experience and the literature and submit short manuscripts that address the nuanced interpretation, limitations, and cost of specific laboratory tests. As with all submissions, these will undergo peer review for content accuracy, as well as relevancy and utility for our core readership before being considered for publication.

A 46-year-old man with poorly controlled hypertension presented with the sudden onset of chest pain and shortness of breath. His blood pressure was 158/96 mm Hg and his left ventricular ejection fraction was less than 20%. He was admitted to the hospital for newly diagnosed heart failure.

SACCULAR AORTIC ANEURYSMS

This case shows the value of carefully examining the chest radiograph, especially behind the heart.

Saccular aneurysms of the descending thoracic aorta are rare and can be easily missed if asymptomatic. They are less common than fusiform aneurysms and may be more prone to rupture. Shang et al¹ identified atherosclerosis as the most frequent cause of saccular aneurysms of the thoracic aorta. However, they can be caused by other inflammatory conditions and infections.¹

Without surgical repair, thoracic aortic aneurysms larger than 6 cm have higher rates of expansion and rupture (a 20% 6-year cumulative risk) than smaller ones.² Mid-descending aortic aneurysms expand faster than those of the ascending aorta.³

Indications for surgery include rupture, severe chest pain, compressive symptoms, large size (eg, ≥ 5.5 cm for asymptomatic descending thoracic aneurysms), and rapid growth rate (≥ 10 mm per year), all of which are associated with a higher mortality rate.⁴

Endovascular grafting should be strongly considered in patients who have significant comorbidities, but this approach may have poorer long-term outcomes compared with open surgery. Blood pressure should be lowered as far as the patient can tolerate without adverse effects, usually with a beta-blocker along with either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker.⁴

Statin therapy to lower the low-density lipoprotein cholesterol level to less than 70 mg/dL is also needed to reduce the risk of complications and cardiovascular disease.

All patients with saccular aortic aneurysm should be followed closely and be evaluated for surgery.

A 46-year-old man with poorly controlled hypertension presented with the sudden onset of chest pain and shortness of breath. His blood pressure was 158/96 mm Hg and his left ventricular ejection fraction was less than 20%. He was admitted to the hospital for newly diagnosed heart failure.

SACCULAR AORTIC ANEURYSMS

This case shows the value of carefully examining the chest radiograph, especially behind the heart.

Saccular aneurysms of the descending thoracic aorta are rare and can be easily missed if asymptomatic. They are less common than fusiform aneurysms and may be more prone to rupture. Shang et al¹ identified atherosclerosis as the most frequent cause of saccular aneurysms of the thoracic aorta. However, they can be caused by other inflammatory conditions and infections.¹

Without surgical repair, thoracic aortic aneurysms larger than 6 cm have higher rates of expansion and rupture (a 20% 6-year cumulative risk) than smaller ones.² Mid-descending aortic aneurysms expand faster than those of the ascending aorta.³

Indications for surgery include rupture, severe chest pain, compressive symptoms, large size (eg, ≥ 5.5 cm for asymptomatic descending thoracic aneurysms), and rapid growth rate (≥ 10 mm per year), all of which are associated with a higher mortality rate.⁴

Endovascular grafting should be strongly considered in patients who have significant comorbidities, but this approach may have poorer long-term outcomes compared with open surgery. Blood pressure should be lowered as far as the patient can tolerate without adverse effects, usually with a beta-blocker along with either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker.⁴

Statin therapy to lower the low-density lipoprotein cholesterol level to less than 70 mg/dL is also needed to reduce the risk of complications and cardiovascular disease.

All patients with saccular aortic aneurysm should be followed closely and be evaluated for surgery.

A 46-year-old man with poorly controlled hypertension presented with the sudden onset of chest pain and shortness of breath. His blood pressure was 158/96 mm Hg and his left ventricular ejection fraction was less than 20%. He was admitted to the hospital for newly diagnosed heart failure.

SACCULAR AORTIC ANEURYSMS

This case shows the value of carefully examining the chest radiograph, especially behind the heart.

Saccular aneurysms of the descending thoracic aorta are rare and can be easily missed if asymptomatic. They are less common than fusiform aneurysms and may be more prone to rupture. Shang et al¹ identified atherosclerosis as the most frequent cause of saccular aneurysms of the thoracic aorta. However, they can be caused by other inflammatory conditions and infections.¹

Without surgical repair, thoracic aortic aneurysms larger than 6 cm have higher rates of expansion and rupture (a 20% 6-year cumulative risk) than smaller ones.² Mid-descending aortic aneurysms expand faster than those of the ascending aorta.³

Indications for surgery include rupture, severe chest pain, compressive symptoms, large size (eg, ≥ 5.5 cm for asymptomatic descending thoracic aneurysms), and rapid growth rate (≥ 10 mm per year), all of which are associated with a higher mortality rate.⁴

Endovascular grafting should be strongly considered in patients who have significant comorbidities, but this approach may have poorer long-term outcomes compared with open surgery. Blood pressure should be lowered as far as the patient can tolerate without adverse effects, usually with a beta-blocker along with either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker.⁴

Statin therapy to lower the low-density lipoprotein cholesterol level to less than 70 mg/dL is also needed to reduce the risk of complications and cardiovascular disease.

All patients with saccular aortic aneurysm should be followed closely and be evaluated for surgery.