The Journal of Family Practice

Prevention of cardiovascular disease (CVD) requires timely identification of people who are at increased risk in order to target effective dietary, lifestyle, or pharmacotherapeutic intervention—or a combination of the 3. Risk factors for CVD are well understood, but the relative impact of each factor on an individual’s overall risk is difficult to accurately quantify, making a validated CVD risk calculator an important clinical tool.

Despite numerous available CVD risk calculators, one best tool has yet to emerge. This state of affairs has limited the ability of front-line providers who are tasked with primary prevention of CVD—including family physicians (FPs)—to provide the best evidence-based recommendations to patients.

Implications of CVD risk assessment

Baseline CVD risk assessment is the cornerstone of recommendations for primary prevention of CVD, including aspirin and statin therapy. Interventions to lower CVD risk are of greatest benefit to those at highest risk at initiation of therapy. Overall, statins reduce the risk of a first cardiovascular event in otherwise healthy people by approximately 25% over 10 years.¹ Because relative risk reduction is fairly consistent across different levels of absolute risk, a 25% relative reduction confers more actual benefit if risk starts at, say, 40% than at 10%.² In that example, the same 25% reduction in relative risk results in 1) an absolute risk reduction of 10% when risk starts at 40%, compared to an absolute risk reduction of 2.5% when risk starts at 10% and 2) a number needed to treat (NNT) of, respectively, 10 and 40 (over 10 years).

Identifying a person with an elevated risk of developing CVD has multiple implications. Ideally, that patient is motivated to pursue positive therapeutic lifestyle modifications and make changes that positively affect long-term CVD risk. Conversely, that asymptomatic person identified as at elevated risk also becomes a patient with a medical problem that might adversely affect insurance premiums and self-esteem, and may trigger the use of medications with cost and potential adverse effects. Although the benefit of preventive therapy is greater for a patient at higher risk of disease, the harm of a therapy is relatively constant across all risk groups. Accurately discriminating high and low risk of CVD is, therefore, imperative.

The venerable Framingham risk score

Cardiovascular risk prediction has its roots in the late 1940s, when primary risk factors for CVD were not well-understood, with the inception of the Framingham Heart Study. (A greater understanding of CVD risk today notwithstanding, coronary artery disease [CAD] remains the leading cause of death among American adults.) In the late 1940s, blood pressure (BP) was recognized as the single most useful variable for identifying people at high risk of CVD; other variables were understood to be predictive as well. A composite score—the Framingham Risk Score (FRS)—was thereby developed to calculate the probability that CVD would occur over 8 years in a person who was initially free of such disease.³

While the benefit of a preventive therapy is greater for those at higher risk of disease, the harm of a therapy is relatively constant across all risk groups.

The original FRS included glucose intolerance and left ventricular hypertrophy (LVH) identified by electrocardiography (EKG) in its algorithm.³ Other, older algorithms also include a family history of premature CVD. In each risk calculator, these variables are treated as dichotomous (Yes or No), but actual risk associated with each variable is in fact more along a continuum. It is now well-recognized that the sensitivity of EKG for accurately detecting LVH is relatively low; more recent algorithms no longer include this component. A family history of premature CVD variably contributes to an individual’s CVD risk; however, its true impact is nearly impossible to accurately quantify, so this variable is also not included in more modern risk calculators.

Caution: The FRS has meaningful limitations

Although the original Framingham cohort has been expanded multiple times since its inception, clinicians and researchers continue to express concern that the predominantly white, middle-class Framingham, Massachusetts, population might not be representative of the United States in general—which would limit the accuracy of the FRS predictive tool when it is applied to a more diverse population. Furthermore, cholesterol-lowering medications were not available when the FRS was first developed. The FRS, therefore, might not accurately estimate risk in more modern populations, in whom aggressive modification of CVD risk factors has resulted in a lower overall rate of atherosclerotic CVD than when the FRS was developed.⁴

Continue to: Although demographic changes have increasingly...

Although demographic changes have increasingly led to an extension of primary prevention strategies for CAD to elderly people, the FRS has been demonstrated to perform less well in patients older than 70 years, particularly men.⁵ An ideal CAD prediction model for elderly people should take into account that, with growing age and frailty, CAD events may be increasingly preempted by death from competing non-coronary causes. In addition, the predictive association of typical CVD risk factors diminishes with increasing age.^6,7 Koller and colleagues developed a CAD risk prediction model that accounted for death from non-coronary causes and was validated specifically in patients 65 years and older. Koller’s prediction model provided well-calibrated risk estimates, but it was still not substantially more accurate than the FRS—illustrating the overall difficulty in predicting CAD risk in elderly people.⁸

Alternative risk calculators have come on the scene

Over the past 2 decades, numerous models have been developed in an attempt to overcome the perceived shortcomings of the FRS. A recent systematic review identified 363 prediction models described in the medical literature prior to July 2013.⁹ The usefulness of most models remains unclear, however, owing to:

• methodological shortcomings,
• considerable heterogeneity in the definitions of outcomes, and
• lack of external validation.

Even models that are well-validated for a specific population suffer from lack of applicability to a broad multinational population.

In the United Kingdom (UK), electronic health record systems now have the QRISK2 tool embedded to calculate 10-year CVD risk. This algorithm incorporates multiple traditional and nontraditional risk factors (TABLE¹⁰). With the inclusion of additional risk factors and validation performed in a population similar to the one from which the algorithm was derived, QRISK2 predicts CVD risk in the UK population more accurately than the modified FRS does.¹⁰ It is not clear, however, whether the same algorithm can be applied to the general US population.

New tool: 2013 ACC/AHA pooled cohort risk equations

In the context of multiple imperfect CVD risk-prediction algorithms, the American College of Cardiology/American Heart Association (ACC/AHA) Task Force on Practice Guidelines published the 2013 Pooled Cohort Risk (PCR) equations to predict 10-year risk of a first atherosclerotic CVD event. The Task Force acknowledged concern that the FRS is based on a cohort that might not accurately represent the general US population. Accordingly, PCR equations were developed from 5 large National Institutes of Health (NIH)-funded cohorts: the Framingham Heart Study, the Framingham Offspring Study, the Atherosclerosis Risk in Communities study, the Cardiovascular Health Study, and the Coronary Artery Risk Development in Young Adults Study.

Continue to: The resulting CVD risk calculator incorporates...

The resulting CVD risk calculator incorporates 4 risk equations: 1 each for African-American and non-Hispanic white males and females.¹¹ Of note, PCR equations are typically used to estimate 10-year CVD risk, but they can be modified to estimate risk over any period. The associated Guideline on the Assessment of Cardiovascular Risk recommends statin therapy for primary prevention of CVD in patients with a predicted 10-year risk ≥7.5% and consideration of statin therapy for patients with a predicted 10-year risk between 5% and 7.5%.¹²

In late 2016, the US Preventive Services Task Force (USPSTF) recommended low- to moderate-dosage statin therapy in adults 40 to 75 years of age without a history of CVD but with at least 1 CVD risk factor (dyslipidemia, diabetes, hypertension, or smoking), and a PCR-calculated 10-year CVD risk of ≥10%. For people with a PCR-calculated risk of 7.5% to 10%, the USPSTF recommended that clinicians “selectively offer” low- to moderate-dosage statin therapy, noting a smaller likelihood of benefit and uncertainty in an individual’s risk prediction.¹³

Pooled cohort risk equations have predictive validity

Estimates are that nearly 50% of US adults and as many as 65% of European adults would be candidates for statin therapy if, using PCR equations, the 2013 ACC/AHA guidelines were broadly applied.¹⁴ Since PCR equations were released, multiple groups have attempted to evaluate the predictive validity of the algorithm in various populations, with mixed findings.

The true impact of systematic CVD risk assessment alone for healthy people has yet to be demonstrated, in terms of hard clinical outcomes.

Data from the 1999-2010 NHANES—the National Health and Nutrition Examination Survey—were used to calculate estimated CVD risk for patients free of atherosclerotic CVD at baseline. Risk prediction using PCR equations was compared to true all-cause and CVD mortality using the National Center for Health Statistics National Death Index. In this large, US adult population without CVD at baseline, PCR-estimated CVD risk was significantly associated with all-cause and CVD-specific mortality risk.¹⁵

In a community-based primary prevention cohort, 39% of participants were found statin-eligible—ie, they had an estimated 10-year CVD risk ≥7.5%—by ACC/AHA guidelines, compared with 14% found statin-eligible by the guidelines of the National Cholesterol Education Program’s 2004 updated “Third Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (ATP III).” Despite the larger percentage, participants who were statin-eligible by ACC/AHA guidelines had an increased hazard ratio for incident CVD compared with those who were statin-eligible by ATP III; investigators concluded that ACC/AHA guidelines using PCR equations were associated with greater accuracy and efficiency in identifying increased risk of incident CVD.¹⁶

Continue to: Pooled cohort risk equations might overestimate CVD risk

 

 

Pooled cohort risk equations might overestimate CVD risk

In contrast, a more recent study followed a large, integrated US health-care delivery system population over 5 years, starting in 2008.¹⁷ In this group of adults without diabetes, PCR equations substantially overestimated actual 5-year risk of CVD in both sexes and across multiple socioeconomic strata. Similar overestimation of CVD risk was demonstrated in non-Hispanic white, non-Hispanic black, Asian/Pacific Islander, and Hispanic subjects. The latter 2 ethnic groups are considered “white or other” in the atherosclerotic CVD risk equation, raising additional concern that PCR equations may not be accurate for broad, multiethnic application.¹⁷ The ACC/AHA Cardiovascular Risk Assessment guideline recognizes this concern, as well, noting that PCR equations may overestimate risk for Hispanic and Asian Americans.¹²

ACC/AHA PCR equations might substantially overestimate CVD risk and lead to expanded use of statins in patient populations for which such treatment has less potential benefit.

Predicted 10-year CVD risk using PCR equations was compared with observed event rates in 3 large-scale primary prevention cohorts: the Women’s Health Study, the Physicians’ Health Study, and the Women’s Health Initiative Observational Study.¹⁸ In each cohort, the ACC/AHA risk prediction algorithm overestimated observed risk by 75% to 150%. The authors concluded that 40% to 50% of the 33 million middle-aged Americans deemed statin-eligible by ACC/AHA guidelines may not have actual CVD risk that exceeds the 7.5% threshold recommended for statin treatment.¹⁸

Therefore, the discrimination of PCR equations—their ability to differentiate between individuals who are more or less likely to develop clinical CVD—is good. The calibration of the equations—the difference between predicted and observed risk—is not as good, however: PCR equations appear to overestimate actual risk in many groups.¹⁵

Additional limitations to pooled cohort risk equations

The predictive value of PCR equations is hampered by several factors:

• Despite expansion of the studied cohorts beyond the original Framingham population, the groups still include people screened for study participation or enrolled in clinical trials. The generalizability of this study population to the diverse population treated in a typical clinical practice is, potentially, limited.
• Use of strategies for primary prevention of CVD (eg, statin therapy, antiplatelet therapy, BP control, blood glucose control) continues to increase. Lowering the risk of CVD in the general population with a broad primary prevention approach effectively widens the gap between observed and equation-predicted CVD risk—and thus strengthens the impression of overestimation of risk by PCR equations.
• Lack of comprehensive surveillance in some studies may result in underassessment of CVD events. In this case, PCR equations would, again, appear to overestimate risk.¹⁹

Novel tools are available; their use is qualified

First, newer risk markers offer additional options for improving risk prediction offered by the ACC/AHA PCR equations: Coronary artery calcium, ankle-brachial index, high-sensitivity C-reactive protein, and a family history of CAD are all independently associated with incident CAD. ACC/AHA guidelines suggest that assessment of 1 or more of these variables might be considered an adjunct when risk assessment using PCR equations alone does not offer information for making a clear treatment decision.¹²

Continue to: Of the 4 risk markers...

Of the 4 risk markers, coronary artery calcium provides the most significant increase in discrimination compared to the FRS alone; comparative data using PCR equations is unavailable.²⁰ ACC/AHA guidelines specifically recommend against routine measurement of carotid intima-media thickness for assessment of risk of a first atherosclerotic event.¹²

Second, a revised set of PCR equations offers improved discrimination and calibration compared to the 2013 PCR equations. A National Institutes of Health (NIH)-sponsored group updated the equations’ cohort by 1) eliminating the original Framingham Heart Study (FHS) data, which was first collected in 1948, and 2) adding data from the Jackson Heart Study and the Multi-Ethnic Study of Atherosclerosis (MESA). Both new cohorts include patient data from 2000 to 2012. Additionally, the NIH group modified the statistical methods used to derive PCR equations. Although these revised PCR equations offer a substantially more accurate estimate of CVD risk, they have not yet been validated for routine clinical use.²¹

Bottom line: In prediction there persists imperfection

It is widely held that CVD risk prediction, with subsequent treatment to reduce identified risk, is an important component of an overall strategy to reduce the burden of CVD. Cardiovascular risk factors, such as BP and lipid values, do show limited improvement among populations in which systematic screening is practiced, but the true impact of systematic CVD risk assessment alone for healthy people has yet to be demonstrated in terms of hard clinical outcomes.²²

The true impact of systematic CVD risk assessment alone for healthy people has yet to be demonstrated in terms of hard clinical outcomes.

CVD risk prediction is most widely used to inform recommendations for statin treatment. However, ACC/AHA PCR equations might substantially overestimate CVD risk and lead to expanded use of statins in patient populations for which such treatment has less potential benefit. Nonetheless, PCR equations do offer good discrimination between higher-risk and lower-risk people.

CVD risk prediction remains an imperfect science—science that is best used as an adjunct to discussion of comprehensive CVD risk factor modification with the individual patient.

CORRESPONDENCE
Jonathon M. Firnhaber, MD, Brody School of Medicine, East Carolina University, 101 Heart Drive, Greenville, NC 27834; [email protected].

Prevention of cardiovascular disease (CVD) requires timely identification of people who are at increased risk in order to target effective dietary, lifestyle, or pharmacotherapeutic intervention—or a combination of the 3. Risk factors for CVD are well understood, but the relative impact of each factor on an individual’s overall risk is difficult to accurately quantify, making a validated CVD risk calculator an important clinical tool.

Despite numerous available CVD risk calculators, one best tool has yet to emerge. This state of affairs has limited the ability of front-line providers who are tasked with primary prevention of CVD—including family physicians (FPs)—to provide the best evidence-based recommendations to patients.

Implications of CVD risk assessment

Baseline CVD risk assessment is the cornerstone of recommendations for primary prevention of CVD, including aspirin and statin therapy. Interventions to lower CVD risk are of greatest benefit to those at highest risk at initiation of therapy. Overall, statins reduce the risk of a first cardiovascular event in otherwise healthy people by approximately 25% over 10 years.¹ Because relative risk reduction is fairly consistent across different levels of absolute risk, a 25% relative reduction confers more actual benefit if risk starts at, say, 40% than at 10%.² In that example, the same 25% reduction in relative risk results in 1) an absolute risk reduction of 10% when risk starts at 40%, compared to an absolute risk reduction of 2.5% when risk starts at 10% and 2) a number needed to treat (NNT) of, respectively, 10 and 40 (over 10 years).

Identifying a person with an elevated risk of developing CVD has multiple implications. Ideally, that patient is motivated to pursue positive therapeutic lifestyle modifications and make changes that positively affect long-term CVD risk. Conversely, that asymptomatic person identified as at elevated risk also becomes a patient with a medical problem that might adversely affect insurance premiums and self-esteem, and may trigger the use of medications with cost and potential adverse effects. Although the benefit of preventive therapy is greater for a patient at higher risk of disease, the harm of a therapy is relatively constant across all risk groups. Accurately discriminating high and low risk of CVD is, therefore, imperative.

The venerable Framingham risk score

Cardiovascular risk prediction has its roots in the late 1940s, when primary risk factors for CVD were not well-understood, with the inception of the Framingham Heart Study. (A greater understanding of CVD risk today notwithstanding, coronary artery disease [CAD] remains the leading cause of death among American adults.) In the late 1940s, blood pressure (BP) was recognized as the single most useful variable for identifying people at high risk of CVD; other variables were understood to be predictive as well. A composite score—the Framingham Risk Score (FRS)—was thereby developed to calculate the probability that CVD would occur over 8 years in a person who was initially free of such disease.³

While the benefit of a preventive therapy is greater for those at higher risk of disease, the harm of a therapy is relatively constant across all risk groups.

The original FRS included glucose intolerance and left ventricular hypertrophy (LVH) identified by electrocardiography (EKG) in its algorithm.³ Other, older algorithms also include a family history of premature CVD. In each risk calculator, these variables are treated as dichotomous (Yes or No), but actual risk associated with each variable is in fact more along a continuum. It is now well-recognized that the sensitivity of EKG for accurately detecting LVH is relatively low; more recent algorithms no longer include this component. A family history of premature CVD variably contributes to an individual’s CVD risk; however, its true impact is nearly impossible to accurately quantify, so this variable is also not included in more modern risk calculators.

Caution: The FRS has meaningful limitations

Although the original Framingham cohort has been expanded multiple times since its inception, clinicians and researchers continue to express concern that the predominantly white, middle-class Framingham, Massachusetts, population might not be representative of the United States in general—which would limit the accuracy of the FRS predictive tool when it is applied to a more diverse population. Furthermore, cholesterol-lowering medications were not available when the FRS was first developed. The FRS, therefore, might not accurately estimate risk in more modern populations, in whom aggressive modification of CVD risk factors has resulted in a lower overall rate of atherosclerotic CVD than when the FRS was developed.⁴

Continue to: Although demographic changes have increasingly...

Although demographic changes have increasingly led to an extension of primary prevention strategies for CAD to elderly people, the FRS has been demonstrated to perform less well in patients older than 70 years, particularly men.⁵ An ideal CAD prediction model for elderly people should take into account that, with growing age and frailty, CAD events may be increasingly preempted by death from competing non-coronary causes. In addition, the predictive association of typical CVD risk factors diminishes with increasing age.^6,7 Koller and colleagues developed a CAD risk prediction model that accounted for death from non-coronary causes and was validated specifically in patients 65 years and older. Koller’s prediction model provided well-calibrated risk estimates, but it was still not substantially more accurate than the FRS—illustrating the overall difficulty in predicting CAD risk in elderly people.⁸

Alternative risk calculators have come on the scene

Over the past 2 decades, numerous models have been developed in an attempt to overcome the perceived shortcomings of the FRS. A recent systematic review identified 363 prediction models described in the medical literature prior to July 2013.⁹ The usefulness of most models remains unclear, however, owing to:

• methodological shortcomings,
• considerable heterogeneity in the definitions of outcomes, and
• lack of external validation.

Even models that are well-validated for a specific population suffer from lack of applicability to a broad multinational population.

In the United Kingdom (UK), electronic health record systems now have the QRISK2 tool embedded to calculate 10-year CVD risk. This algorithm incorporates multiple traditional and nontraditional risk factors (TABLE¹⁰). With the inclusion of additional risk factors and validation performed in a population similar to the one from which the algorithm was derived, QRISK2 predicts CVD risk in the UK population more accurately than the modified FRS does.¹⁰ It is not clear, however, whether the same algorithm can be applied to the general US population.

New tool: 2013 ACC/AHA pooled cohort risk equations

In the context of multiple imperfect CVD risk-prediction algorithms, the American College of Cardiology/American Heart Association (ACC/AHA) Task Force on Practice Guidelines published the 2013 Pooled Cohort Risk (PCR) equations to predict 10-year risk of a first atherosclerotic CVD event. The Task Force acknowledged concern that the FRS is based on a cohort that might not accurately represent the general US population. Accordingly, PCR equations were developed from 5 large National Institutes of Health (NIH)-funded cohorts: the Framingham Heart Study, the Framingham Offspring Study, the Atherosclerosis Risk in Communities study, the Cardiovascular Health Study, and the Coronary Artery Risk Development in Young Adults Study.

Continue to: The resulting CVD risk calculator incorporates...

The resulting CVD risk calculator incorporates 4 risk equations: 1 each for African-American and non-Hispanic white males and females.¹¹ Of note, PCR equations are typically used to estimate 10-year CVD risk, but they can be modified to estimate risk over any period. The associated Guideline on the Assessment of Cardiovascular Risk recommends statin therapy for primary prevention of CVD in patients with a predicted 10-year risk ≥7.5% and consideration of statin therapy for patients with a predicted 10-year risk between 5% and 7.5%.¹²

In late 2016, the US Preventive Services Task Force (USPSTF) recommended low- to moderate-dosage statin therapy in adults 40 to 75 years of age without a history of CVD but with at least 1 CVD risk factor (dyslipidemia, diabetes, hypertension, or smoking), and a PCR-calculated 10-year CVD risk of ≥10%. For people with a PCR-calculated risk of 7.5% to 10%, the USPSTF recommended that clinicians “selectively offer” low- to moderate-dosage statin therapy, noting a smaller likelihood of benefit and uncertainty in an individual’s risk prediction.¹³

Pooled cohort risk equations have predictive validity

Estimates are that nearly 50% of US adults and as many as 65% of European adults would be candidates for statin therapy if, using PCR equations, the 2013 ACC/AHA guidelines were broadly applied.¹⁴ Since PCR equations were released, multiple groups have attempted to evaluate the predictive validity of the algorithm in various populations, with mixed findings.

The true impact of systematic CVD risk assessment alone for healthy people has yet to be demonstrated, in terms of hard clinical outcomes.

Data from the 1999-2010 NHANES—the National Health and Nutrition Examination Survey—were used to calculate estimated CVD risk for patients free of atherosclerotic CVD at baseline. Risk prediction using PCR equations was compared to true all-cause and CVD mortality using the National Center for Health Statistics National Death Index. In this large, US adult population without CVD at baseline, PCR-estimated CVD risk was significantly associated with all-cause and CVD-specific mortality risk.¹⁵

In a community-based primary prevention cohort, 39% of participants were found statin-eligible—ie, they had an estimated 10-year CVD risk ≥7.5%—by ACC/AHA guidelines, compared with 14% found statin-eligible by the guidelines of the National Cholesterol Education Program’s 2004 updated “Third Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (ATP III).” Despite the larger percentage, participants who were statin-eligible by ACC/AHA guidelines had an increased hazard ratio for incident CVD compared with those who were statin-eligible by ATP III; investigators concluded that ACC/AHA guidelines using PCR equations were associated with greater accuracy and efficiency in identifying increased risk of incident CVD.¹⁶

Continue to: Pooled cohort risk equations might overestimate CVD risk

 

 

Pooled cohort risk equations might overestimate CVD risk

In contrast, a more recent study followed a large, integrated US health-care delivery system population over 5 years, starting in 2008.¹⁷ In this group of adults without diabetes, PCR equations substantially overestimated actual 5-year risk of CVD in both sexes and across multiple socioeconomic strata. Similar overestimation of CVD risk was demonstrated in non-Hispanic white, non-Hispanic black, Asian/Pacific Islander, and Hispanic subjects. The latter 2 ethnic groups are considered “white or other” in the atherosclerotic CVD risk equation, raising additional concern that PCR equations may not be accurate for broad, multiethnic application.¹⁷ The ACC/AHA Cardiovascular Risk Assessment guideline recognizes this concern, as well, noting that PCR equations may overestimate risk for Hispanic and Asian Americans.¹²

ACC/AHA PCR equations might substantially overestimate CVD risk and lead to expanded use of statins in patient populations for which such treatment has less potential benefit.

Predicted 10-year CVD risk using PCR equations was compared with observed event rates in 3 large-scale primary prevention cohorts: the Women’s Health Study, the Physicians’ Health Study, and the Women’s Health Initiative Observational Study.¹⁸ In each cohort, the ACC/AHA risk prediction algorithm overestimated observed risk by 75% to 150%. The authors concluded that 40% to 50% of the 33 million middle-aged Americans deemed statin-eligible by ACC/AHA guidelines may not have actual CVD risk that exceeds the 7.5% threshold recommended for statin treatment.¹⁸

Therefore, the discrimination of PCR equations—their ability to differentiate between individuals who are more or less likely to develop clinical CVD—is good. The calibration of the equations—the difference between predicted and observed risk—is not as good, however: PCR equations appear to overestimate actual risk in many groups.¹⁵

Additional limitations to pooled cohort risk equations

The predictive value of PCR equations is hampered by several factors:

• Despite expansion of the studied cohorts beyond the original Framingham population, the groups still include people screened for study participation or enrolled in clinical trials. The generalizability of this study population to the diverse population treated in a typical clinical practice is, potentially, limited.
• Use of strategies for primary prevention of CVD (eg, statin therapy, antiplatelet therapy, BP control, blood glucose control) continues to increase. Lowering the risk of CVD in the general population with a broad primary prevention approach effectively widens the gap between observed and equation-predicted CVD risk—and thus strengthens the impression of overestimation of risk by PCR equations.
• Lack of comprehensive surveillance in some studies may result in underassessment of CVD events. In this case, PCR equations would, again, appear to overestimate risk.¹⁹

Novel tools are available; their use is qualified

First, newer risk markers offer additional options for improving risk prediction offered by the ACC/AHA PCR equations: Coronary artery calcium, ankle-brachial index, high-sensitivity C-reactive protein, and a family history of CAD are all independently associated with incident CAD. ACC/AHA guidelines suggest that assessment of 1 or more of these variables might be considered an adjunct when risk assessment using PCR equations alone does not offer information for making a clear treatment decision.¹²

Continue to: Of the 4 risk markers...

Of the 4 risk markers, coronary artery calcium provides the most significant increase in discrimination compared to the FRS alone; comparative data using PCR equations is unavailable.²⁰ ACC/AHA guidelines specifically recommend against routine measurement of carotid intima-media thickness for assessment of risk of a first atherosclerotic event.¹²

Second, a revised set of PCR equations offers improved discrimination and calibration compared to the 2013 PCR equations. A National Institutes of Health (NIH)-sponsored group updated the equations’ cohort by 1) eliminating the original Framingham Heart Study (FHS) data, which was first collected in 1948, and 2) adding data from the Jackson Heart Study and the Multi-Ethnic Study of Atherosclerosis (MESA). Both new cohorts include patient data from 2000 to 2012. Additionally, the NIH group modified the statistical methods used to derive PCR equations. Although these revised PCR equations offer a substantially more accurate estimate of CVD risk, they have not yet been validated for routine clinical use.²¹

Bottom line: In prediction there persists imperfection

It is widely held that CVD risk prediction, with subsequent treatment to reduce identified risk, is an important component of an overall strategy to reduce the burden of CVD. Cardiovascular risk factors, such as BP and lipid values, do show limited improvement among populations in which systematic screening is practiced, but the true impact of systematic CVD risk assessment alone for healthy people has yet to be demonstrated in terms of hard clinical outcomes.²²

The true impact of systematic CVD risk assessment alone for healthy people has yet to be demonstrated in terms of hard clinical outcomes.

CVD risk prediction is most widely used to inform recommendations for statin treatment. However, ACC/AHA PCR equations might substantially overestimate CVD risk and lead to expanded use of statins in patient populations for which such treatment has less potential benefit. Nonetheless, PCR equations do offer good discrimination between higher-risk and lower-risk people.

CVD risk prediction remains an imperfect science—science that is best used as an adjunct to discussion of comprehensive CVD risk factor modification with the individual patient.

CORRESPONDENCE
Jonathon M. Firnhaber, MD, Brody School of Medicine, East Carolina University, 101 Heart Drive, Greenville, NC 27834; [email protected].

Prevention of cardiovascular disease (CVD) requires timely identification of people who are at increased risk in order to target effective dietary, lifestyle, or pharmacotherapeutic intervention—or a combination of the 3. Risk factors for CVD are well understood, but the relative impact of each factor on an individual’s overall risk is difficult to accurately quantify, making a validated CVD risk calculator an important clinical tool.

Despite numerous available CVD risk calculators, one best tool has yet to emerge. This state of affairs has limited the ability of front-line providers who are tasked with primary prevention of CVD—including family physicians (FPs)—to provide the best evidence-based recommendations to patients.

Implications of CVD risk assessment

Baseline CVD risk assessment is the cornerstone of recommendations for primary prevention of CVD, including aspirin and statin therapy. Interventions to lower CVD risk are of greatest benefit to those at highest risk at initiation of therapy. Overall, statins reduce the risk of a first cardiovascular event in otherwise healthy people by approximately 25% over 10 years.¹ Because relative risk reduction is fairly consistent across different levels of absolute risk, a 25% relative reduction confers more actual benefit if risk starts at, say, 40% than at 10%.² In that example, the same 25% reduction in relative risk results in 1) an absolute risk reduction of 10% when risk starts at 40%, compared to an absolute risk reduction of 2.5% when risk starts at 10% and 2) a number needed to treat (NNT) of, respectively, 10 and 40 (over 10 years).

Identifying a person with an elevated risk of developing CVD has multiple implications. Ideally, that patient is motivated to pursue positive therapeutic lifestyle modifications and make changes that positively affect long-term CVD risk. Conversely, that asymptomatic person identified as at elevated risk also becomes a patient with a medical problem that might adversely affect insurance premiums and self-esteem, and may trigger the use of medications with cost and potential adverse effects. Although the benefit of preventive therapy is greater for a patient at higher risk of disease, the harm of a therapy is relatively constant across all risk groups. Accurately discriminating high and low risk of CVD is, therefore, imperative.

The venerable Framingham risk score

Cardiovascular risk prediction has its roots in the late 1940s, when primary risk factors for CVD were not well-understood, with the inception of the Framingham Heart Study. (A greater understanding of CVD risk today notwithstanding, coronary artery disease [CAD] remains the leading cause of death among American adults.) In the late 1940s, blood pressure (BP) was recognized as the single most useful variable for identifying people at high risk of CVD; other variables were understood to be predictive as well. A composite score—the Framingham Risk Score (FRS)—was thereby developed to calculate the probability that CVD would occur over 8 years in a person who was initially free of such disease.³

While the benefit of a preventive therapy is greater for those at higher risk of disease, the harm of a therapy is relatively constant across all risk groups.

The original FRS included glucose intolerance and left ventricular hypertrophy (LVH) identified by electrocardiography (EKG) in its algorithm.³ Other, older algorithms also include a family history of premature CVD. In each risk calculator, these variables are treated as dichotomous (Yes or No), but actual risk associated with each variable is in fact more along a continuum. It is now well-recognized that the sensitivity of EKG for accurately detecting LVH is relatively low; more recent algorithms no longer include this component. A family history of premature CVD variably contributes to an individual’s CVD risk; however, its true impact is nearly impossible to accurately quantify, so this variable is also not included in more modern risk calculators.

Caution: The FRS has meaningful limitations

Although the original Framingham cohort has been expanded multiple times since its inception, clinicians and researchers continue to express concern that the predominantly white, middle-class Framingham, Massachusetts, population might not be representative of the United States in general—which would limit the accuracy of the FRS predictive tool when it is applied to a more diverse population. Furthermore, cholesterol-lowering medications were not available when the FRS was first developed. The FRS, therefore, might not accurately estimate risk in more modern populations, in whom aggressive modification of CVD risk factors has resulted in a lower overall rate of atherosclerotic CVD than when the FRS was developed.⁴

Continue to: Although demographic changes have increasingly...

Although demographic changes have increasingly led to an extension of primary prevention strategies for CAD to elderly people, the FRS has been demonstrated to perform less well in patients older than 70 years, particularly men.⁵ An ideal CAD prediction model for elderly people should take into account that, with growing age and frailty, CAD events may be increasingly preempted by death from competing non-coronary causes. In addition, the predictive association of typical CVD risk factors diminishes with increasing age.^6,7 Koller and colleagues developed a CAD risk prediction model that accounted for death from non-coronary causes and was validated specifically in patients 65 years and older. Koller’s prediction model provided well-calibrated risk estimates, but it was still not substantially more accurate than the FRS—illustrating the overall difficulty in predicting CAD risk in elderly people.⁸

Alternative risk calculators have come on the scene

Over the past 2 decades, numerous models have been developed in an attempt to overcome the perceived shortcomings of the FRS. A recent systematic review identified 363 prediction models described in the medical literature prior to July 2013.⁹ The usefulness of most models remains unclear, however, owing to:

• methodological shortcomings,
• considerable heterogeneity in the definitions of outcomes, and
• lack of external validation.

Even models that are well-validated for a specific population suffer from lack of applicability to a broad multinational population.

In the United Kingdom (UK), electronic health record systems now have the QRISK2 tool embedded to calculate 10-year CVD risk. This algorithm incorporates multiple traditional and nontraditional risk factors (TABLE¹⁰). With the inclusion of additional risk factors and validation performed in a population similar to the one from which the algorithm was derived, QRISK2 predicts CVD risk in the UK population more accurately than the modified FRS does.¹⁰ It is not clear, however, whether the same algorithm can be applied to the general US population.

New tool: 2013 ACC/AHA pooled cohort risk equations

In the context of multiple imperfect CVD risk-prediction algorithms, the American College of Cardiology/American Heart Association (ACC/AHA) Task Force on Practice Guidelines published the 2013 Pooled Cohort Risk (PCR) equations to predict 10-year risk of a first atherosclerotic CVD event. The Task Force acknowledged concern that the FRS is based on a cohort that might not accurately represent the general US population. Accordingly, PCR equations were developed from 5 large National Institutes of Health (NIH)-funded cohorts: the Framingham Heart Study, the Framingham Offspring Study, the Atherosclerosis Risk in Communities study, the Cardiovascular Health Study, and the Coronary Artery Risk Development in Young Adults Study.

Continue to: The resulting CVD risk calculator incorporates...

The resulting CVD risk calculator incorporates 4 risk equations: 1 each for African-American and non-Hispanic white males and females.¹¹ Of note, PCR equations are typically used to estimate 10-year CVD risk, but they can be modified to estimate risk over any period. The associated Guideline on the Assessment of Cardiovascular Risk recommends statin therapy for primary prevention of CVD in patients with a predicted 10-year risk ≥7.5% and consideration of statin therapy for patients with a predicted 10-year risk between 5% and 7.5%.¹²

In late 2016, the US Preventive Services Task Force (USPSTF) recommended low- to moderate-dosage statin therapy in adults 40 to 75 years of age without a history of CVD but with at least 1 CVD risk factor (dyslipidemia, diabetes, hypertension, or smoking), and a PCR-calculated 10-year CVD risk of ≥10%. For people with a PCR-calculated risk of 7.5% to 10%, the USPSTF recommended that clinicians “selectively offer” low- to moderate-dosage statin therapy, noting a smaller likelihood of benefit and uncertainty in an individual’s risk prediction.¹³

Pooled cohort risk equations have predictive validity

Estimates are that nearly 50% of US adults and as many as 65% of European adults would be candidates for statin therapy if, using PCR equations, the 2013 ACC/AHA guidelines were broadly applied.¹⁴ Since PCR equations were released, multiple groups have attempted to evaluate the predictive validity of the algorithm in various populations, with mixed findings.

The true impact of systematic CVD risk assessment alone for healthy people has yet to be demonstrated, in terms of hard clinical outcomes.

Data from the 1999-2010 NHANES—the National Health and Nutrition Examination Survey—were used to calculate estimated CVD risk for patients free of atherosclerotic CVD at baseline. Risk prediction using PCR equations was compared to true all-cause and CVD mortality using the National Center for Health Statistics National Death Index. In this large, US adult population without CVD at baseline, PCR-estimated CVD risk was significantly associated with all-cause and CVD-specific mortality risk.¹⁵

In a community-based primary prevention cohort, 39% of participants were found statin-eligible—ie, they had an estimated 10-year CVD risk ≥7.5%—by ACC/AHA guidelines, compared with 14% found statin-eligible by the guidelines of the National Cholesterol Education Program’s 2004 updated “Third Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (ATP III).” Despite the larger percentage, participants who were statin-eligible by ACC/AHA guidelines had an increased hazard ratio for incident CVD compared with those who were statin-eligible by ATP III; investigators concluded that ACC/AHA guidelines using PCR equations were associated with greater accuracy and efficiency in identifying increased risk of incident CVD.¹⁶

Continue to: Pooled cohort risk equations might overestimate CVD risk

 

 

Pooled cohort risk equations might overestimate CVD risk

In contrast, a more recent study followed a large, integrated US health-care delivery system population over 5 years, starting in 2008.¹⁷ In this group of adults without diabetes, PCR equations substantially overestimated actual 5-year risk of CVD in both sexes and across multiple socioeconomic strata. Similar overestimation of CVD risk was demonstrated in non-Hispanic white, non-Hispanic black, Asian/Pacific Islander, and Hispanic subjects. The latter 2 ethnic groups are considered “white or other” in the atherosclerotic CVD risk equation, raising additional concern that PCR equations may not be accurate for broad, multiethnic application.¹⁷ The ACC/AHA Cardiovascular Risk Assessment guideline recognizes this concern, as well, noting that PCR equations may overestimate risk for Hispanic and Asian Americans.¹²

ACC/AHA PCR equations might substantially overestimate CVD risk and lead to expanded use of statins in patient populations for which such treatment has less potential benefit.

Predicted 10-year CVD risk using PCR equations was compared with observed event rates in 3 large-scale primary prevention cohorts: the Women’s Health Study, the Physicians’ Health Study, and the Women’s Health Initiative Observational Study.¹⁸ In each cohort, the ACC/AHA risk prediction algorithm overestimated observed risk by 75% to 150%. The authors concluded that 40% to 50% of the 33 million middle-aged Americans deemed statin-eligible by ACC/AHA guidelines may not have actual CVD risk that exceeds the 7.5% threshold recommended for statin treatment.¹⁸

Therefore, the discrimination of PCR equations—their ability to differentiate between individuals who are more or less likely to develop clinical CVD—is good. The calibration of the equations—the difference between predicted and observed risk—is not as good, however: PCR equations appear to overestimate actual risk in many groups.¹⁵

Additional limitations to pooled cohort risk equations

The predictive value of PCR equations is hampered by several factors:

• Despite expansion of the studied cohorts beyond the original Framingham population, the groups still include people screened for study participation or enrolled in clinical trials. The generalizability of this study population to the diverse population treated in a typical clinical practice is, potentially, limited.
• Use of strategies for primary prevention of CVD (eg, statin therapy, antiplatelet therapy, BP control, blood glucose control) continues to increase. Lowering the risk of CVD in the general population with a broad primary prevention approach effectively widens the gap between observed and equation-predicted CVD risk—and thus strengthens the impression of overestimation of risk by PCR equations.
• Lack of comprehensive surveillance in some studies may result in underassessment of CVD events. In this case, PCR equations would, again, appear to overestimate risk.¹⁹

Novel tools are available; their use is qualified

First, newer risk markers offer additional options for improving risk prediction offered by the ACC/AHA PCR equations: Coronary artery calcium, ankle-brachial index, high-sensitivity C-reactive protein, and a family history of CAD are all independently associated with incident CAD. ACC/AHA guidelines suggest that assessment of 1 or more of these variables might be considered an adjunct when risk assessment using PCR equations alone does not offer information for making a clear treatment decision.¹²

Continue to: Of the 4 risk markers...

Of the 4 risk markers, coronary artery calcium provides the most significant increase in discrimination compared to the FRS alone; comparative data using PCR equations is unavailable.²⁰ ACC/AHA guidelines specifically recommend against routine measurement of carotid intima-media thickness for assessment of risk of a first atherosclerotic event.¹²

Second, a revised set of PCR equations offers improved discrimination and calibration compared to the 2013 PCR equations. A National Institutes of Health (NIH)-sponsored group updated the equations’ cohort by 1) eliminating the original Framingham Heart Study (FHS) data, which was first collected in 1948, and 2) adding data from the Jackson Heart Study and the Multi-Ethnic Study of Atherosclerosis (MESA). Both new cohorts include patient data from 2000 to 2012. Additionally, the NIH group modified the statistical methods used to derive PCR equations. Although these revised PCR equations offer a substantially more accurate estimate of CVD risk, they have not yet been validated for routine clinical use.²¹

Bottom line: In prediction there persists imperfection

It is widely held that CVD risk prediction, with subsequent treatment to reduce identified risk, is an important component of an overall strategy to reduce the burden of CVD. Cardiovascular risk factors, such as BP and lipid values, do show limited improvement among populations in which systematic screening is practiced, but the true impact of systematic CVD risk assessment alone for healthy people has yet to be demonstrated in terms of hard clinical outcomes.²²

The true impact of systematic CVD risk assessment alone for healthy people has yet to be demonstrated in terms of hard clinical outcomes.

CVD risk prediction is most widely used to inform recommendations for statin treatment. However, ACC/AHA PCR equations might substantially overestimate CVD risk and lead to expanded use of statins in patient populations for which such treatment has less potential benefit. Nonetheless, PCR equations do offer good discrimination between higher-risk and lower-risk people.

CVD risk prediction remains an imperfect science—science that is best used as an adjunct to discussion of comprehensive CVD risk factor modification with the individual patient.

CORRESPONDENCE
Jonathon M. Firnhaber, MD, Brody School of Medicine, East Carolina University, 101 Heart Drive, Greenville, NC 27834; [email protected].

EVIDENCE SUMMARY

A 2016 Cochrane systematic review identified 2 double-blind RCTs that evaluated statins for preventing cognitive decline and dementia in patients with either risk factors or a history of vascular disease.¹ The authors couldn’t perform a meta-analysis because of heterogeneity.

Statins don’t prevent dementia

The first RCT found that 5804 patients (70-82 years old with pre-existing vascular disease or increased risk because of smoking, hypertension, or diabetes) manifested equivalent cognitive decline at 3.5 years after random assignment to pravastatin 40 mg/d or placebo.² Investigators measured cognition with the Mini-Mental State Exam (MMSE), which scores cognitive function on a scale of 0 to 30, with higher numbers indicating better function (mean difference [MD] at follow-up=0.06 points; 95% confidence interval [CI], −0.04 to 0.16).

A second RCT evaluated simvastatin 40 mg/d or placebo for as long as 5 years in 20,536 patients 40 to 80 years of age with a history of coronary artery disease or diabetes.³ The study excluded patients with dementia at baseline. The odds of developing dementia didn’t differ between groups (odds ratio=1.0; 95% CI, 0.61-1.65).

Both studies were originally designed to measure cardiovascular outcomes. The authors rated both as high quality with a low risk of bias.

A contrast to earlier, lower-quality studies

These results contrast with an earlier meta-analysis based on one of the previously described RCTs and lower-quality evidence (16 cohort studies and 3 case-control studies) that found using statins to be associated with lower relative risk (RR) of dementia than not using a statin (all-type dementia RR=0.82; 95% CI, 0.69-0.97; Alzheimer’s disease RR=0.70; 95% CI, 0.60-0.83).^3,4

The total patient population was more than 2 million and varied widely. Duration of statin use and type of statin (simvastatin, atorvastatin, fluvastatin, pravastatin, rosuvastatin) also varied. The authors noted potential bias in results for 2 reasons: Cross-sectional studies included patients with impaired cognition who were less likely to be prescribed statins, and statin use was determined by patient self-report.

Statins don’t treat dementia

A Cochrane review that included 4 RCTs with 1154 patients, 50 to 90 years old, assessed the effect of ≥6 months of statin therapy (atorvastatin 80 mg/d or simvastatin 40-80 mg/d) on the course of Alzheimer’s disease and vascular dementia.⁵ Most patients had mild to moderate dementia and most were also taking an anticholinesterase inhibitor.

Continue to: All studies reported...

All studies reported outcomes using the Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), scored 0 to 70, with lower numbers indicating better function, and the MMSE. Results of statin use were equivalent to placebo (ADAS-Cog MD= −0.26; 95% CI, −1.05 to 0.52; MMSE MD= −0.32; 95% CI, −0.71 to 0.06).

But do they slow its progression?

In contrast, a case-control study of 6431 patients with mild-to-moderate Alzheimer’s disease concluded that statin use was associated with slower progression of AD.⁶ Using cholinesterase inhibitor discontinuation as a proxy for worsening dementia, researchers noted that patients with early statin exposure (719 patients) had a lower rate of cholinesterase discontinuation than patients who didn’t receive early statin therapy (RR=0.85; 95% CI, 0.76-0.95).

A 2016 systematic review attempted to identify randomized clinical trials evaluating the effects of statin withdrawal in dementia.⁷ None were found.

RECOMMENDATIONS

Based primarily on post-marketing surveillance data, the US Food and Drug Administration (FDA) has warned that memory loss and confusion are occasionally associated with statin use from within one day to several years of initiation.⁸ The FDA indicated that such symptoms are rare, not associated with dementia or clinically significant cognitive decline, and resolve with discontinuation of the medication.

EVIDENCE SUMMARY

A 2016 Cochrane systematic review identified 2 double-blind RCTs that evaluated statins for preventing cognitive decline and dementia in patients with either risk factors or a history of vascular disease.¹ The authors couldn’t perform a meta-analysis because of heterogeneity.

Statins don’t prevent dementia

The first RCT found that 5804 patients (70-82 years old with pre-existing vascular disease or increased risk because of smoking, hypertension, or diabetes) manifested equivalent cognitive decline at 3.5 years after random assignment to pravastatin 40 mg/d or placebo.² Investigators measured cognition with the Mini-Mental State Exam (MMSE), which scores cognitive function on a scale of 0 to 30, with higher numbers indicating better function (mean difference [MD] at follow-up=0.06 points; 95% confidence interval [CI], −0.04 to 0.16).

A second RCT evaluated simvastatin 40 mg/d or placebo for as long as 5 years in 20,536 patients 40 to 80 years of age with a history of coronary artery disease or diabetes.³ The study excluded patients with dementia at baseline. The odds of developing dementia didn’t differ between groups (odds ratio=1.0; 95% CI, 0.61-1.65).

Both studies were originally designed to measure cardiovascular outcomes. The authors rated both as high quality with a low risk of bias.

A contrast to earlier, lower-quality studies

These results contrast with an earlier meta-analysis based on one of the previously described RCTs and lower-quality evidence (16 cohort studies and 3 case-control studies) that found using statins to be associated with lower relative risk (RR) of dementia than not using a statin (all-type dementia RR=0.82; 95% CI, 0.69-0.97; Alzheimer’s disease RR=0.70; 95% CI, 0.60-0.83).^3,4

The total patient population was more than 2 million and varied widely. Duration of statin use and type of statin (simvastatin, atorvastatin, fluvastatin, pravastatin, rosuvastatin) also varied. The authors noted potential bias in results for 2 reasons: Cross-sectional studies included patients with impaired cognition who were less likely to be prescribed statins, and statin use was determined by patient self-report.

Statins don’t treat dementia

A Cochrane review that included 4 RCTs with 1154 patients, 50 to 90 years old, assessed the effect of ≥6 months of statin therapy (atorvastatin 80 mg/d or simvastatin 40-80 mg/d) on the course of Alzheimer’s disease and vascular dementia.⁵ Most patients had mild to moderate dementia and most were also taking an anticholinesterase inhibitor.

Continue to: All studies reported...

All studies reported outcomes using the Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), scored 0 to 70, with lower numbers indicating better function, and the MMSE. Results of statin use were equivalent to placebo (ADAS-Cog MD= −0.26; 95% CI, −1.05 to 0.52; MMSE MD= −0.32; 95% CI, −0.71 to 0.06).

But do they slow its progression?

In contrast, a case-control study of 6431 patients with mild-to-moderate Alzheimer’s disease concluded that statin use was associated with slower progression of AD.⁶ Using cholinesterase inhibitor discontinuation as a proxy for worsening dementia, researchers noted that patients with early statin exposure (719 patients) had a lower rate of cholinesterase discontinuation than patients who didn’t receive early statin therapy (RR=0.85; 95% CI, 0.76-0.95).

A 2016 systematic review attempted to identify randomized clinical trials evaluating the effects of statin withdrawal in dementia.⁷ None were found.

RECOMMENDATIONS

Based primarily on post-marketing surveillance data, the US Food and Drug Administration (FDA) has warned that memory loss and confusion are occasionally associated with statin use from within one day to several years of initiation.⁸ The FDA indicated that such symptoms are rare, not associated with dementia or clinically significant cognitive decline, and resolve with discontinuation of the medication.

EVIDENCE SUMMARY

A 2016 Cochrane systematic review identified 2 double-blind RCTs that evaluated statins for preventing cognitive decline and dementia in patients with either risk factors or a history of vascular disease.¹ The authors couldn’t perform a meta-analysis because of heterogeneity.

Statins don’t prevent dementia

The first RCT found that 5804 patients (70-82 years old with pre-existing vascular disease or increased risk because of smoking, hypertension, or diabetes) manifested equivalent cognitive decline at 3.5 years after random assignment to pravastatin 40 mg/d or placebo.² Investigators measured cognition with the Mini-Mental State Exam (MMSE), which scores cognitive function on a scale of 0 to 30, with higher numbers indicating better function (mean difference [MD] at follow-up=0.06 points; 95% confidence interval [CI], −0.04 to 0.16).

A second RCT evaluated simvastatin 40 mg/d or placebo for as long as 5 years in 20,536 patients 40 to 80 years of age with a history of coronary artery disease or diabetes.³ The study excluded patients with dementia at baseline. The odds of developing dementia didn’t differ between groups (odds ratio=1.0; 95% CI, 0.61-1.65).

Both studies were originally designed to measure cardiovascular outcomes. The authors rated both as high quality with a low risk of bias.

A contrast to earlier, lower-quality studies

These results contrast with an earlier meta-analysis based on one of the previously described RCTs and lower-quality evidence (16 cohort studies and 3 case-control studies) that found using statins to be associated with lower relative risk (RR) of dementia than not using a statin (all-type dementia RR=0.82; 95% CI, 0.69-0.97; Alzheimer’s disease RR=0.70; 95% CI, 0.60-0.83).^3,4

The total patient population was more than 2 million and varied widely. Duration of statin use and type of statin (simvastatin, atorvastatin, fluvastatin, pravastatin, rosuvastatin) also varied. The authors noted potential bias in results for 2 reasons: Cross-sectional studies included patients with impaired cognition who were less likely to be prescribed statins, and statin use was determined by patient self-report.

Statins don’t treat dementia

A Cochrane review that included 4 RCTs with 1154 patients, 50 to 90 years old, assessed the effect of ≥6 months of statin therapy (atorvastatin 80 mg/d or simvastatin 40-80 mg/d) on the course of Alzheimer’s disease and vascular dementia.⁵ Most patients had mild to moderate dementia and most were also taking an anticholinesterase inhibitor.

Continue to: All studies reported...

All studies reported outcomes using the Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), scored 0 to 70, with lower numbers indicating better function, and the MMSE. Results of statin use were equivalent to placebo (ADAS-Cog MD= −0.26; 95% CI, −1.05 to 0.52; MMSE MD= −0.32; 95% CI, −0.71 to 0.06).

But do they slow its progression?

In contrast, a case-control study of 6431 patients with mild-to-moderate Alzheimer’s disease concluded that statin use was associated with slower progression of AD.⁶ Using cholinesterase inhibitor discontinuation as a proxy for worsening dementia, researchers noted that patients with early statin exposure (719 patients) had a lower rate of cholinesterase discontinuation than patients who didn’t receive early statin therapy (RR=0.85; 95% CI, 0.76-0.95).

A 2016 systematic review attempted to identify randomized clinical trials evaluating the effects of statin withdrawal in dementia.⁷ None were found.

RECOMMENDATIONS

Based primarily on post-marketing surveillance data, the US Food and Drug Administration (FDA) has warned that memory loss and confusion are occasionally associated with statin use from within one day to several years of initiation.⁸ The FDA indicated that such symptoms are rare, not associated with dementia or clinically significant cognitive decline, and resolve with discontinuation of the medication.

EVIDENCE SUMMARY

A systematic review and meta-analysis of observational studies examined the risk of hypomagnesemia, defined in various studies as serum magnesium levels of 1.6, 1.7, or 1.8 mg/dL.¹ Two cohort studies, one case-control study, and 6 cross-sectional studies met inclusion criteria; 115,455 patients were enrolled. The studies were significantly heterogeneous (I²=89.1%), because of varying study designs, population sizes, and population characteristics.

PPI use increased the risk of hypomagnesemia (pooled odds ratio [OR]=1.5; 95% confidence interval [CI], 1.1-2.0) after adjustment for possible confounders such as use of diuretics.

Risk rises with long-term use, but severe hypomagnesemia is rare

Two more recent cohort studies produced conflicting results. Of 414 patients in a managed care cohort who received long-term PPIs, only 8 had mild hypomagnesemia (1.2-1.5 mg/dL) on nearly 14% of their combined 289 measurements. At final measurement, all patients had normal serum magnesium levels.²

A cross-sectional analysis of data from a retrospective cohort analysis of 9818 patients in the Netherlands found that any PPI use during the previous year was associated with an increased risk of hypomagnesemia (serum magnesium <1.73 mg/dL) compared with no use (adjusted OR=2; 95% CI, 1.4-2.9).³ The risk was greatest with use longer than 182 days (OR=3.0; 95% CI, 1.7-5.2). As with studies included in the meta-analysis, this study examined laboratory values exclusively. Only 3 of 724 PPI users had a serum magnesium level below 1.2 mg/dL, the point at which symptoms usually occur.

Case-control studies produce conflicting results

Two recent case-control studies also produced conflicting results. The first compared 154 outpatients who used PPIs for at least 6 months (mean, 27.5 months) with 84 nonusers.⁴ No association was found with hypomagnesemia (2.17 mg/dL vs 2.19 mg/dL), and none of the patients had a serum magnesium level below 1.7 mg/dL. The control group was poorly defined, however, and the study excluded patients taking diuretics.

Conversely, a study that compared 366 patients hospitalized with a primary or secondary diagnosis of hypomagnesemia (determined from an insurance claims database and defined as the presence of ICD-10 codes for hypomagnesemia or magnesium deficiency) with 1464 matched controls found that hospitalized patients with hypomagnesemia were more likely than controls to be current PPI users (adjusted OR=1.4; 95% CI, 1.1-1.9).⁵ Whether hypomagnesemia was the cause of the hospitalizations or an incidental finding wasn’t clear.

Concurrent use of diuretics and loop diuretics can increase risk

In a subgroup analysis of the second case-control study, PPI users who also used diuretics had an increased risk of hypomagnesemia (adjusted OR=1.7; 95% CI, 1.1-2.7) compared with patients who weren’t taking diuretics (adjusted OR=1.3; 95% CI, 0.8-1.9).⁵

Continue to: A comparison of the use of loop diuretics and...

A comparison of the use of loop diuretics and thiazides by patients taking PPIs found that concurrent use of loop diuretics increased serum magnesium reduction (−0.08 mg/dL; 95% CI, −0.14 to −0.02), but thiazides didn’t. Numbers were small: Of the 45 participants taking both a PPI and a loop diuretic, only 5 had hypomagnesemia (OR=7.2; 95% CI, 1.7-30.8).³

RECOMMENDATIONS

In 2011, the US Food and Drug Administration (FDA) warned of a possible increased risk of hypomagnesemia in patients taking PPIs long-term. The FDA advisory panel recommended evaluating serum magnesium before beginning long-term PPI therapy and in patients concurrently taking diuretics, digoxin, or other medications associated with hypomagnesemia.⁶

EVIDENCE SUMMARY

A systematic review and meta-analysis of observational studies examined the risk of hypomagnesemia, defined in various studies as serum magnesium levels of 1.6, 1.7, or 1.8 mg/dL.¹ Two cohort studies, one case-control study, and 6 cross-sectional studies met inclusion criteria; 115,455 patients were enrolled. The studies were significantly heterogeneous (I²=89.1%), because of varying study designs, population sizes, and population characteristics.

PPI use increased the risk of hypomagnesemia (pooled odds ratio [OR]=1.5; 95% confidence interval [CI], 1.1-2.0) after adjustment for possible confounders such as use of diuretics.

Risk rises with long-term use, but severe hypomagnesemia is rare

Two more recent cohort studies produced conflicting results. Of 414 patients in a managed care cohort who received long-term PPIs, only 8 had mild hypomagnesemia (1.2-1.5 mg/dL) on nearly 14% of their combined 289 measurements. At final measurement, all patients had normal serum magnesium levels.²

A cross-sectional analysis of data from a retrospective cohort analysis of 9818 patients in the Netherlands found that any PPI use during the previous year was associated with an increased risk of hypomagnesemia (serum magnesium <1.73 mg/dL) compared with no use (adjusted OR=2; 95% CI, 1.4-2.9).³ The risk was greatest with use longer than 182 days (OR=3.0; 95% CI, 1.7-5.2). As with studies included in the meta-analysis, this study examined laboratory values exclusively. Only 3 of 724 PPI users had a serum magnesium level below 1.2 mg/dL, the point at which symptoms usually occur.

Case-control studies produce conflicting results

Two recent case-control studies also produced conflicting results. The first compared 154 outpatients who used PPIs for at least 6 months (mean, 27.5 months) with 84 nonusers.⁴ No association was found with hypomagnesemia (2.17 mg/dL vs 2.19 mg/dL), and none of the patients had a serum magnesium level below 1.7 mg/dL. The control group was poorly defined, however, and the study excluded patients taking diuretics.

Conversely, a study that compared 366 patients hospitalized with a primary or secondary diagnosis of hypomagnesemia (determined from an insurance claims database and defined as the presence of ICD-10 codes for hypomagnesemia or magnesium deficiency) with 1464 matched controls found that hospitalized patients with hypomagnesemia were more likely than controls to be current PPI users (adjusted OR=1.4; 95% CI, 1.1-1.9).⁵ Whether hypomagnesemia was the cause of the hospitalizations or an incidental finding wasn’t clear.

Concurrent use of diuretics and loop diuretics can increase risk

In a subgroup analysis of the second case-control study, PPI users who also used diuretics had an increased risk of hypomagnesemia (adjusted OR=1.7; 95% CI, 1.1-2.7) compared with patients who weren’t taking diuretics (adjusted OR=1.3; 95% CI, 0.8-1.9).⁵

Continue to: A comparison of the use of loop diuretics and...

A comparison of the use of loop diuretics and thiazides by patients taking PPIs found that concurrent use of loop diuretics increased serum magnesium reduction (−0.08 mg/dL; 95% CI, −0.14 to −0.02), but thiazides didn’t. Numbers were small: Of the 45 participants taking both a PPI and a loop diuretic, only 5 had hypomagnesemia (OR=7.2; 95% CI, 1.7-30.8).³

RECOMMENDATIONS

In 2011, the US Food and Drug Administration (FDA) warned of a possible increased risk of hypomagnesemia in patients taking PPIs long-term. The FDA advisory panel recommended evaluating serum magnesium before beginning long-term PPI therapy and in patients concurrently taking diuretics, digoxin, or other medications associated with hypomagnesemia.⁶

EVIDENCE SUMMARY

A systematic review and meta-analysis of observational studies examined the risk of hypomagnesemia, defined in various studies as serum magnesium levels of 1.6, 1.7, or 1.8 mg/dL.¹ Two cohort studies, one case-control study, and 6 cross-sectional studies met inclusion criteria; 115,455 patients were enrolled. The studies were significantly heterogeneous (I²=89.1%), because of varying study designs, population sizes, and population characteristics.

PPI use increased the risk of hypomagnesemia (pooled odds ratio [OR]=1.5; 95% confidence interval [CI], 1.1-2.0) after adjustment for possible confounders such as use of diuretics.

Risk rises with long-term use, but severe hypomagnesemia is rare

Two more recent cohort studies produced conflicting results. Of 414 patients in a managed care cohort who received long-term PPIs, only 8 had mild hypomagnesemia (1.2-1.5 mg/dL) on nearly 14% of their combined 289 measurements. At final measurement, all patients had normal serum magnesium levels.²

A cross-sectional analysis of data from a retrospective cohort analysis of 9818 patients in the Netherlands found that any PPI use during the previous year was associated with an increased risk of hypomagnesemia (serum magnesium <1.73 mg/dL) compared with no use (adjusted OR=2; 95% CI, 1.4-2.9).³ The risk was greatest with use longer than 182 days (OR=3.0; 95% CI, 1.7-5.2). As with studies included in the meta-analysis, this study examined laboratory values exclusively. Only 3 of 724 PPI users had a serum magnesium level below 1.2 mg/dL, the point at which symptoms usually occur.

Case-control studies produce conflicting results

Two recent case-control studies also produced conflicting results. The first compared 154 outpatients who used PPIs for at least 6 months (mean, 27.5 months) with 84 nonusers.⁴ No association was found with hypomagnesemia (2.17 mg/dL vs 2.19 mg/dL), and none of the patients had a serum magnesium level below 1.7 mg/dL. The control group was poorly defined, however, and the study excluded patients taking diuretics.

Conversely, a study that compared 366 patients hospitalized with a primary or secondary diagnosis of hypomagnesemia (determined from an insurance claims database and defined as the presence of ICD-10 codes for hypomagnesemia or magnesium deficiency) with 1464 matched controls found that hospitalized patients with hypomagnesemia were more likely than controls to be current PPI users (adjusted OR=1.4; 95% CI, 1.1-1.9).⁵ Whether hypomagnesemia was the cause of the hospitalizations or an incidental finding wasn’t clear.

Concurrent use of diuretics and loop diuretics can increase risk

In a subgroup analysis of the second case-control study, PPI users who also used diuretics had an increased risk of hypomagnesemia (adjusted OR=1.7; 95% CI, 1.1-2.7) compared with patients who weren’t taking diuretics (adjusted OR=1.3; 95% CI, 0.8-1.9).⁵

Continue to: A comparison of the use of loop diuretics and...

A comparison of the use of loop diuretics and thiazides by patients taking PPIs found that concurrent use of loop diuretics increased serum magnesium reduction (−0.08 mg/dL; 95% CI, −0.14 to −0.02), but thiazides didn’t. Numbers were small: Of the 45 participants taking both a PPI and a loop diuretic, only 5 had hypomagnesemia (OR=7.2; 95% CI, 1.7-30.8).³

RECOMMENDATIONS

In 2011, the US Food and Drug Administration (FDA) warned of a possible increased risk of hypomagnesemia in patients taking PPIs long-term. The FDA advisory panel recommended evaluating serum magnesium before beginning long-term PPI therapy and in patients concurrently taking diuretics, digoxin, or other medications associated with hypomagnesemia.⁶

Musculoskeletal complaints are one of the top reasons patients visit family physicians, with more than 24 million encounters per year.¹ Two articles in this month’s issue of JFP discuss treatments for musculoskeletal pain.

The article by Drs. Stephen and Peter Carek summarizes the value of specific exercises for hip and knee osteoarthritis (OA), chronic back pain, chronic shoulder pain, Achilles tendinitis, and lateral epicondylitis. This month’s PURL summarizes a negative randomized trial of treatment of knee OA with the popular over-the-counter combination of glucosamine and chondroitin. The findings? The group taking placebo actually had superior pain relief at 6 months!

What else works … and doesn’t? You may find that the following 4 “pearls,” taken from the literature, are also useful to know as you seek to manage patients’ musculoskeletal pain.

Studies remind us to harness the placebo effect, rather than dismiss it.

Pearl #1. Don’t use diazepam (valium) for acute low back pain. It doesn’t improve pain or function for this back pain. One hundred fourteen patients with acute low back pain were randomized to naproxen 500 mg bid as needed plus either placebo or diazepam 5 mg, 1 or 2 tablets, every 12 hours prn. At 7 days, 32% of the diazepam group reported moderate to severe pain and 22% of the placebo group did.²

Pearl #2. Use naproxen alone when treating acute low back pain. Three hundred twenty-three patients with acute low back pain were randomized to receive naproxen 500 mg bid plus placebo; naproxen plus oxycodone/acetaminophen; or naproxen plus cyclobenzaprine.³ At 7 days and 3 months, pain and function scores did not differ between groups.

Pearl #3. Don’t inject knees with corticosteroids. Enroll these patients in exercise and walking programs, which do provide benefit. One hundred forty patients with moderately severe knee OA were randomized to saline or triamcinolone 40 mg intra-articular injections every 3 months for 2 years.⁴ There was no difference in pain or function scores measured every 3 months and there was more cartilage degeneration in the triamcinolone group.

Continue to: Pearl #4

Pearl #4. Don’t dismiss the placebo effect. Eighty-three patients with chronic low back pain were randomized to either continue their current pain medications or to continue their current pain medication plus a placebo tablet twice daily for 3 weeks.⁵ They were told that placebos can have significant pain-relieving qualities. At 3 weeks, the patients taking placebo had less pain than those not taking placebo.

I’m not sure if we should start prescribing placebos, but this study is a strong reminder that we should harness the placebo effect, rather than dismiss it.

Musculoskeletal complaints are one of the top reasons patients visit family physicians, with more than 24 million encounters per year.¹ Two articles in this month’s issue of JFP discuss treatments for musculoskeletal pain.

The article by Drs. Stephen and Peter Carek summarizes the value of specific exercises for hip and knee osteoarthritis (OA), chronic back pain, chronic shoulder pain, Achilles tendinitis, and lateral epicondylitis. This month’s PURL summarizes a negative randomized trial of treatment of knee OA with the popular over-the-counter combination of glucosamine and chondroitin. The findings? The group taking placebo actually had superior pain relief at 6 months!

What else works … and doesn’t? You may find that the following 4 “pearls,” taken from the literature, are also useful to know as you seek to manage patients’ musculoskeletal pain.

Studies remind us to harness the placebo effect, rather than dismiss it.

Pearl #1. Don’t use diazepam (valium) for acute low back pain. It doesn’t improve pain or function for this back pain. One hundred fourteen patients with acute low back pain were randomized to naproxen 500 mg bid as needed plus either placebo or diazepam 5 mg, 1 or 2 tablets, every 12 hours prn. At 7 days, 32% of the diazepam group reported moderate to severe pain and 22% of the placebo group did.²

Pearl #2. Use naproxen alone when treating acute low back pain. Three hundred twenty-three patients with acute low back pain were randomized to receive naproxen 500 mg bid plus placebo; naproxen plus oxycodone/acetaminophen; or naproxen plus cyclobenzaprine.³ At 7 days and 3 months, pain and function scores did not differ between groups.

Pearl #3. Don’t inject knees with corticosteroids. Enroll these patients in exercise and walking programs, which do provide benefit. One hundred forty patients with moderately severe knee OA were randomized to saline or triamcinolone 40 mg intra-articular injections every 3 months for 2 years.⁴ There was no difference in pain or function scores measured every 3 months and there was more cartilage degeneration in the triamcinolone group.

Continue to: Pearl #4

Pearl #4. Don’t dismiss the placebo effect. Eighty-three patients with chronic low back pain were randomized to either continue their current pain medications or to continue their current pain medication plus a placebo tablet twice daily for 3 weeks.⁵ They were told that placebos can have significant pain-relieving qualities. At 3 weeks, the patients taking placebo had less pain than those not taking placebo.

I’m not sure if we should start prescribing placebos, but this study is a strong reminder that we should harness the placebo effect, rather than dismiss it.

Musculoskeletal complaints are one of the top reasons patients visit family physicians, with more than 24 million encounters per year.¹ Two articles in this month’s issue of JFP discuss treatments for musculoskeletal pain.

The article by Drs. Stephen and Peter Carek summarizes the value of specific exercises for hip and knee osteoarthritis (OA), chronic back pain, chronic shoulder pain, Achilles tendinitis, and lateral epicondylitis. This month’s PURL summarizes a negative randomized trial of treatment of knee OA with the popular over-the-counter combination of glucosamine and chondroitin. The findings? The group taking placebo actually had superior pain relief at 6 months!

What else works … and doesn’t? You may find that the following 4 “pearls,” taken from the literature, are also useful to know as you seek to manage patients’ musculoskeletal pain.

Studies remind us to harness the placebo effect, rather than dismiss it.

Pearl #1. Don’t use diazepam (valium) for acute low back pain. It doesn’t improve pain or function for this back pain. One hundred fourteen patients with acute low back pain were randomized to naproxen 500 mg bid as needed plus either placebo or diazepam 5 mg, 1 or 2 tablets, every 12 hours prn. At 7 days, 32% of the diazepam group reported moderate to severe pain and 22% of the placebo group did.²

Pearl #2. Use naproxen alone when treating acute low back pain. Three hundred twenty-three patients with acute low back pain were randomized to receive naproxen 500 mg bid plus placebo; naproxen plus oxycodone/acetaminophen; or naproxen plus cyclobenzaprine.³ At 7 days and 3 months, pain and function scores did not differ between groups.

Pearl #3. Don’t inject knees with corticosteroids. Enroll these patients in exercise and walking programs, which do provide benefit. One hundred forty patients with moderately severe knee OA were randomized to saline or triamcinolone 40 mg intra-articular injections every 3 months for 2 years.⁴ There was no difference in pain or function scores measured every 3 months and there was more cartilage degeneration in the triamcinolone group.

Continue to: Pearl #4

Pearl #4. Don’t dismiss the placebo effect. Eighty-three patients with chronic low back pain were randomized to either continue their current pain medications or to continue their current pain medication plus a placebo tablet twice daily for 3 weeks.⁵ They were told that placebos can have significant pain-relieving qualities. At 3 weeks, the patients taking placebo had less pain than those not taking placebo.

I’m not sure if we should start prescribing placebos, but this study is a strong reminder that we should harness the placebo effect, rather than dismiss it.

A 58-year-old woman with a history of hepatitis C, liver cirrhosis, hepatocellular carcinoma, hypothyroidism, and peripheral neuropathy presented to our clinic with left ear pain and blisters on her lips, nose, and mouth. On exam, the patient’s left tympanic membrane was opaque, and she had multiple 3- to 5-mm irregularly shaped ulcers on her right buccal mucosa, gingiva, and lips. She was given a diagnosis of acute otitis media and prescribed a course of amoxicillin. The physician, who was uncertain about the cause of her gingivostomatitis, took a “shotgun approach” and prescribed a nystatin/diphenhydramine/lidocaine mouthwash.

Three weeks later, the patient returned complaining of cloudy urine, dysuria, fever, vomiting, and “pink eye.” On exam, her right eye was mildly injected with no drainage. She had normal eye movements and no ophthalmoplegia. We diagnosed viral (vs allergic) conjunctivitis and pyelonephritis in this patient and advised her to use lubricant eyedrops and an oral antihistamine for the eye. We also started her on cefpodoxime (200 mg bid for 10 days) for pyelonephritis.

Three days later, the patient called our clinic and said that her right eye was not improving. We prescribed ofloxacin ophthalmic drops, 1 to 2 drops every 6 hours, for presumed bacterial conjunctivitis.

Four days later, she returned to our clinic; she had been using the ofloxacin drops and antihistamine but was experiencing worsening symptoms, including itching of her right eye, associated blurriness, and decreased vision. She had been using a warm compress on the eye and found that it was getting sticky and crusted. A gray corneal opacity was seen on physical exam, and a fluorescein exam was performed (FIGURE).

WHAT IS YOUR DIAGNOSIS?
HOW WOULD YOU TREAT THIS PATIENT?

 

 

Diagnosis: Herpes simplex virus keratitis

The patient was sent to the ophthalmology clinic, where a slit-lamp examination of the right eye showed 3+ injection, large dendritic epithelial defects spanning the majority of the cornea (with 10% haze), and trace nuclear sclerosis of the lens. These findings were consistent with a diagnosis of herpes simplex virus (HSV) keratitis, with a likely neurotrophic component (decreased sensation of the affected eye compared with that of the other eye). There was no evidence of secondary infection.

Discussion

The global incidence of HSV keratitis is approximately 1.5 million, including 40,000 new cases of monocular visual impairment or blindness each year.¹ Primary infection with HSV-1 occurs following direct contact with infected mucosa or skin surfaces and inoculation. (Our patient likely transferred the infection by touching her eyes after touching her nose or mouth.) The virus remains in sensory ganglia for the lifetime of the host. Most ocular disease is thought to represent recurrent HSV (rather than a primary ocular infection).² It has been proposed that HSV-1 latency may also occur in the cornea.

The symptoms of HSV keratitis include eye pain, redness, blurred vision, tearing, discharge, and sensitivity to light.

The symptoms of HSV keratitis include eye pain, redness, blurred vision, tearing, discharge, and sensitivity to light.

The 4 diagnostic categories

There are 4 categories of HSV keratitis, based on the location of the infection: epithelial, stromal, endotheliitis, and neurotrophic keratopathy.

Epithelial. The most common form, epithelial HSV manifests as dendritic or geographic lesions of the cornea.³ Geographic lesions occur when a dendrite widens and assumes an amoeboid shape.

Continue to: Stromal

Stromal. Stromal involvement accounts for 20% to 25% of presentations⁴ and may cause significant anterior chamber inflammation. Vision loss can result from permanent stromal scarring.⁵

Endotheliitis. Keratic precipitates (on top of stromal and epithelial edema) and a mild-to-moderate iritis are signs of endotheliitis.⁵

Neurotrophic keratopathy. This form of HSV keratitis is associated with corneal hypoesthesia or complete anesthesia secondary to damage of the corneal nerves, which can occur in any form of ocular HSV. Anesthesia may lead to nonhealing corneal epithelial defects.⁶ These defects, which are generally oval lesions, do not represent active viral disease and are made worse by antiviral drops. These lesions may cause stromal scarring, corneal perforation, or secondary bacterial infection.

Treatment consists of supportive care using artificial tears and prophylactic antibiotic eye drops, if appropriate; more advanced ophthalmologic treatments may be needed for advanced disease.⁷

Continue to: Other conditions, including conjunctivitis, have similar symptoms

Other conditions, including conjunctivitis, have similar symptoms

The differential for redness of the eye includes conditions such as conjunctivitis, glaucoma, and keratitis.

Conjunctivitis of any form—bacterial, viral, allergic, or toxic—involves injection of both the palpebral and bulbar conjunctiva.

Acute angle closure glaucoma can involve symptoms of headache, malaise, nausea, and vomiting. In addition, the pupil is fixed in mid-dilation, and the cornea becomes hazy.

Anterior uveitis/iritis causes sensitivity to light in both the affected and unaffected eyes, as well as ciliary flush (a red ring around the iris). Typically, there is no eye discharge.

Bacterial keratitis causes foreign body sensation and purulent discharge. This form of keratitis usually occurs due to improper wear of contact lenses.

Continue to: Viral keratitis...

Viral keratitis is characterized by photophobia, foreign body sensation, and watery discharge. A faint branching grey opacity may be seen on penlight exam, and dendrites may be seen with fluorescein.

Scleritis involves severe, boring pain of the eye in addition to photophobia and headache. It is usually associated with systemic inflammatory disorders.

Subconjunctival hemorrhage is asymptomatic and occurs following trauma.

Cellulitis manifests following trauma with a deep violet color and marked edema.

Continue to: Standard Tx

 

 

Standard Tx: Antiviral medications

Topical antiviral therapy is the standard treatment for epithelial HSV keratitis, although oral antiviral medications are equally effective. A randomized trial found that using an oral agent in addition to a topical antiviral did not improve outcomes.⁸ A 2015 systematic review found that topical antivirals acyclovir, ganciclovir, brivudine, trifluridine were equally effective in treatment outcome; 90% of patients healed within 2 weeks.⁹

Recurrent ocular HSV-1 infections are treated in the same way as the initial infection. Recurrent infection can be prevented with daily suppressive therapy. In one study, patients who took suppressive therapy (acyclovir 400 mg bid) for 1 year had 19% recurrence of ocular infection vs 32% in the placebo group.¹⁰

It’s always better to consider a diagnosis of primary oral HSV infection than to treat candida and pain with a mixed medication mouthwash.

Prompt Tx is key. If the infection is superficial—involving only the outer layer of the cornea (epithelium)—the eye should heal without scarring with proper treatment. However, if the infection is not promptly treated or if deeper layers are involved, scarring of the cornea may occur. This can lead to vision loss or blindness.

Continue to: A missed opportunity for an earlier diagnosis

 

 

A missed opportunity for an earlier diagnosis

This case highlights the importance of conducting a thorough exam to identify findings that could shift the diagnosis from a simple allergic, viral, or bacterial conjunctivitis. It is always better to consider primary oral HSV infection than resort to a “shotgun approach” of treating candida and pain with an oral mixture. In this case, the ulcers and vesicles on the buccal mucosa, gingiva, and lips were a missed sign of primary HSV infection. Making this diagnosis might have prevented the ocular disease, as the treatment would have been an oral antiviral.

If conjunctivitis is refractory to usual management, the patient must be seen to rule out dangerous eye diagnoses such as HSV keratitis, preseptal or orbital cellulitis, or in the worst case, acute angle closure glaucoma. If there is uncertainty regarding diagnosis, a fluorescein exam is helpful. This simple in-office exam can facilitate a referral to Ophthalmology or the emergency department for a slit-lamp exam and appropriate therapy.

Our patient was started on valacyclovir 1 g bid, trifluridine eyedrops (5×/d), and erythromycin ophthalmic ointment (3×/d), with Ophthalmology follow-up in 1 week.

CORRESPONDENCE
John Spittler, MD, 3055 Roslyn St, Suite 100, Denver, CO 80238; [email protected]

A 58-year-old woman with a history of hepatitis C, liver cirrhosis, hepatocellular carcinoma, hypothyroidism, and peripheral neuropathy presented to our clinic with left ear pain and blisters on her lips, nose, and mouth. On exam, the patient’s left tympanic membrane was opaque, and she had multiple 3- to 5-mm irregularly shaped ulcers on her right buccal mucosa, gingiva, and lips. She was given a diagnosis of acute otitis media and prescribed a course of amoxicillin. The physician, who was uncertain about the cause of her gingivostomatitis, took a “shotgun approach” and prescribed a nystatin/diphenhydramine/lidocaine mouthwash.

Three weeks later, the patient returned complaining of cloudy urine, dysuria, fever, vomiting, and “pink eye.” On exam, her right eye was mildly injected with no drainage. She had normal eye movements and no ophthalmoplegia. We diagnosed viral (vs allergic) conjunctivitis and pyelonephritis in this patient and advised her to use lubricant eyedrops and an oral antihistamine for the eye. We also started her on cefpodoxime (200 mg bid for 10 days) for pyelonephritis.

Three days later, the patient called our clinic and said that her right eye was not improving. We prescribed ofloxacin ophthalmic drops, 1 to 2 drops every 6 hours, for presumed bacterial conjunctivitis.

Four days later, she returned to our clinic; she had been using the ofloxacin drops and antihistamine but was experiencing worsening symptoms, including itching of her right eye, associated blurriness, and decreased vision. She had been using a warm compress on the eye and found that it was getting sticky and crusted. A gray corneal opacity was seen on physical exam, and a fluorescein exam was performed (FIGURE).

WHAT IS YOUR DIAGNOSIS?
HOW WOULD YOU TREAT THIS PATIENT?

 

 

Diagnosis: Herpes simplex virus keratitis

The patient was sent to the ophthalmology clinic, where a slit-lamp examination of the right eye showed 3+ injection, large dendritic epithelial defects spanning the majority of the cornea (with 10% haze), and trace nuclear sclerosis of the lens. These findings were consistent with a diagnosis of herpes simplex virus (HSV) keratitis, with a likely neurotrophic component (decreased sensation of the affected eye compared with that of the other eye). There was no evidence of secondary infection.

Discussion

The global incidence of HSV keratitis is approximately 1.5 million, including 40,000 new cases of monocular visual impairment or blindness each year.¹ Primary infection with HSV-1 occurs following direct contact with infected mucosa or skin surfaces and inoculation. (Our patient likely transferred the infection by touching her eyes after touching her nose or mouth.) The virus remains in sensory ganglia for the lifetime of the host. Most ocular disease is thought to represent recurrent HSV (rather than a primary ocular infection).² It has been proposed that HSV-1 latency may also occur in the cornea.

The symptoms of HSV keratitis include eye pain, redness, blurred vision, tearing, discharge, and sensitivity to light.

The symptoms of HSV keratitis include eye pain, redness, blurred vision, tearing, discharge, and sensitivity to light.

The 4 diagnostic categories

There are 4 categories of HSV keratitis, based on the location of the infection: epithelial, stromal, endotheliitis, and neurotrophic keratopathy.

Epithelial. The most common form, epithelial HSV manifests as dendritic or geographic lesions of the cornea.³ Geographic lesions occur when a dendrite widens and assumes an amoeboid shape.

Continue to: Stromal

Stromal. Stromal involvement accounts for 20% to 25% of presentations⁴ and may cause significant anterior chamber inflammation. Vision loss can result from permanent stromal scarring.⁵

Endotheliitis. Keratic precipitates (on top of stromal and epithelial edema) and a mild-to-moderate iritis are signs of endotheliitis.⁵

Neurotrophic keratopathy. This form of HSV keratitis is associated with corneal hypoesthesia or complete anesthesia secondary to damage of the corneal nerves, which can occur in any form of ocular HSV. Anesthesia may lead to nonhealing corneal epithelial defects.⁶ These defects, which are generally oval lesions, do not represent active viral disease and are made worse by antiviral drops. These lesions may cause stromal scarring, corneal perforation, or secondary bacterial infection.

Treatment consists of supportive care using artificial tears and prophylactic antibiotic eye drops, if appropriate; more advanced ophthalmologic treatments may be needed for advanced disease.⁷

Continue to: Other conditions, including conjunctivitis, have similar symptoms

Other conditions, including conjunctivitis, have similar symptoms

The differential for redness of the eye includes conditions such as conjunctivitis, glaucoma, and keratitis.

Conjunctivitis of any form—bacterial, viral, allergic, or toxic—involves injection of both the palpebral and bulbar conjunctiva.

Acute angle closure glaucoma can involve symptoms of headache, malaise, nausea, and vomiting. In addition, the pupil is fixed in mid-dilation, and the cornea becomes hazy.

Anterior uveitis/iritis causes sensitivity to light in both the affected and unaffected eyes, as well as ciliary flush (a red ring around the iris). Typically, there is no eye discharge.

Bacterial keratitis causes foreign body sensation and purulent discharge. This form of keratitis usually occurs due to improper wear of contact lenses.

Continue to: Viral keratitis...

Viral keratitis is characterized by photophobia, foreign body sensation, and watery discharge. A faint branching grey opacity may be seen on penlight exam, and dendrites may be seen with fluorescein.

Scleritis involves severe, boring pain of the eye in addition to photophobia and headache. It is usually associated with systemic inflammatory disorders.

Subconjunctival hemorrhage is asymptomatic and occurs following trauma.

Cellulitis manifests following trauma with a deep violet color and marked edema.

Continue to: Standard Tx

 

 

Standard Tx: Antiviral medications

Topical antiviral therapy is the standard treatment for epithelial HSV keratitis, although oral antiviral medications are equally effective. A randomized trial found that using an oral agent in addition to a topical antiviral did not improve outcomes.⁸ A 2015 systematic review found that topical antivirals acyclovir, ganciclovir, brivudine, trifluridine were equally effective in treatment outcome; 90% of patients healed within 2 weeks.⁹

Recurrent ocular HSV-1 infections are treated in the same way as the initial infection. Recurrent infection can be prevented with daily suppressive therapy. In one study, patients who took suppressive therapy (acyclovir 400 mg bid) for 1 year had 19% recurrence of ocular infection vs 32% in the placebo group.¹⁰

It’s always better to consider a diagnosis of primary oral HSV infection than to treat candida and pain with a mixed medication mouthwash.

Prompt Tx is key. If the infection is superficial—involving only the outer layer of the cornea (epithelium)—the eye should heal without scarring with proper treatment. However, if the infection is not promptly treated or if deeper layers are involved, scarring of the cornea may occur. This can lead to vision loss or blindness.

Continue to: A missed opportunity for an earlier diagnosis

 

 

A missed opportunity for an earlier diagnosis

This case highlights the importance of conducting a thorough exam to identify findings that could shift the diagnosis from a simple allergic, viral, or bacterial conjunctivitis. It is always better to consider primary oral HSV infection than resort to a “shotgun approach” of treating candida and pain with an oral mixture. In this case, the ulcers and vesicles on the buccal mucosa, gingiva, and lips were a missed sign of primary HSV infection. Making this diagnosis might have prevented the ocular disease, as the treatment would have been an oral antiviral.

If conjunctivitis is refractory to usual management, the patient must be seen to rule out dangerous eye diagnoses such as HSV keratitis, preseptal or orbital cellulitis, or in the worst case, acute angle closure glaucoma. If there is uncertainty regarding diagnosis, a fluorescein exam is helpful. This simple in-office exam can facilitate a referral to Ophthalmology or the emergency department for a slit-lamp exam and appropriate therapy.

Our patient was started on valacyclovir 1 g bid, trifluridine eyedrops (5×/d), and erythromycin ophthalmic ointment (3×/d), with Ophthalmology follow-up in 1 week.

CORRESPONDENCE
John Spittler, MD, 3055 Roslyn St, Suite 100, Denver, CO 80238; [email protected]

A 58-year-old woman with a history of hepatitis C, liver cirrhosis, hepatocellular carcinoma, hypothyroidism, and peripheral neuropathy presented to our clinic with left ear pain and blisters on her lips, nose, and mouth. On exam, the patient’s left tympanic membrane was opaque, and she had multiple 3- to 5-mm irregularly shaped ulcers on her right buccal mucosa, gingiva, and lips. She was given a diagnosis of acute otitis media and prescribed a course of amoxicillin. The physician, who was uncertain about the cause of her gingivostomatitis, took a “shotgun approach” and prescribed a nystatin/diphenhydramine/lidocaine mouthwash.

Three weeks later, the patient returned complaining of cloudy urine, dysuria, fever, vomiting, and “pink eye.” On exam, her right eye was mildly injected with no drainage. She had normal eye movements and no ophthalmoplegia. We diagnosed viral (vs allergic) conjunctivitis and pyelonephritis in this patient and advised her to use lubricant eyedrops and an oral antihistamine for the eye. We also started her on cefpodoxime (200 mg bid for 10 days) for pyelonephritis.

Three days later, the patient called our clinic and said that her right eye was not improving. We prescribed ofloxacin ophthalmic drops, 1 to 2 drops every 6 hours, for presumed bacterial conjunctivitis.

Four days later, she returned to our clinic; she had been using the ofloxacin drops and antihistamine but was experiencing worsening symptoms, including itching of her right eye, associated blurriness, and decreased vision. She had been using a warm compress on the eye and found that it was getting sticky and crusted. A gray corneal opacity was seen on physical exam, and a fluorescein exam was performed (FIGURE).

WHAT IS YOUR DIAGNOSIS?
HOW WOULD YOU TREAT THIS PATIENT?

 

 

Diagnosis: Herpes simplex virus keratitis

The patient was sent to the ophthalmology clinic, where a slit-lamp examination of the right eye showed 3+ injection, large dendritic epithelial defects spanning the majority of the cornea (with 10% haze), and trace nuclear sclerosis of the lens. These findings were consistent with a diagnosis of herpes simplex virus (HSV) keratitis, with a likely neurotrophic component (decreased sensation of the affected eye compared with that of the other eye). There was no evidence of secondary infection.

Discussion

The global incidence of HSV keratitis is approximately 1.5 million, including 40,000 new cases of monocular visual impairment or blindness each year.¹ Primary infection with HSV-1 occurs following direct contact with infected mucosa or skin surfaces and inoculation. (Our patient likely transferred the infection by touching her eyes after touching her nose or mouth.) The virus remains in sensory ganglia for the lifetime of the host. Most ocular disease is thought to represent recurrent HSV (rather than a primary ocular infection).² It has been proposed that HSV-1 latency may also occur in the cornea.

The symptoms of HSV keratitis include eye pain, redness, blurred vision, tearing, discharge, and sensitivity to light.

The symptoms of HSV keratitis include eye pain, redness, blurred vision, tearing, discharge, and sensitivity to light.

The 4 diagnostic categories

There are 4 categories of HSV keratitis, based on the location of the infection: epithelial, stromal, endotheliitis, and neurotrophic keratopathy.

Epithelial. The most common form, epithelial HSV manifests as dendritic or geographic lesions of the cornea.³ Geographic lesions occur when a dendrite widens and assumes an amoeboid shape.

Continue to: Stromal

Stromal. Stromal involvement accounts for 20% to 25% of presentations⁴ and may cause significant anterior chamber inflammation. Vision loss can result from permanent stromal scarring.⁵

Endotheliitis. Keratic precipitates (on top of stromal and epithelial edema) and a mild-to-moderate iritis are signs of endotheliitis.⁵

Neurotrophic keratopathy. This form of HSV keratitis is associated with corneal hypoesthesia or complete anesthesia secondary to damage of the corneal nerves, which can occur in any form of ocular HSV. Anesthesia may lead to nonhealing corneal epithelial defects.⁶ These defects, which are generally oval lesions, do not represent active viral disease and are made worse by antiviral drops. These lesions may cause stromal scarring, corneal perforation, or secondary bacterial infection.

Treatment consists of supportive care using artificial tears and prophylactic antibiotic eye drops, if appropriate; more advanced ophthalmologic treatments may be needed for advanced disease.⁷

Continue to: Other conditions, including conjunctivitis, have similar symptoms

Other conditions, including conjunctivitis, have similar symptoms

The differential for redness of the eye includes conditions such as conjunctivitis, glaucoma, and keratitis.

Conjunctivitis of any form—bacterial, viral, allergic, or toxic—involves injection of both the palpebral and bulbar conjunctiva.

Acute angle closure glaucoma can involve symptoms of headache, malaise, nausea, and vomiting. In addition, the pupil is fixed in mid-dilation, and the cornea becomes hazy.

Anterior uveitis/iritis causes sensitivity to light in both the affected and unaffected eyes, as well as ciliary flush (a red ring around the iris). Typically, there is no eye discharge.

Bacterial keratitis causes foreign body sensation and purulent discharge. This form of keratitis usually occurs due to improper wear of contact lenses.

Continue to: Viral keratitis...

Viral keratitis is characterized by photophobia, foreign body sensation, and watery discharge. A faint branching grey opacity may be seen on penlight exam, and dendrites may be seen with fluorescein.

Scleritis involves severe, boring pain of the eye in addition to photophobia and headache. It is usually associated with systemic inflammatory disorders.

Subconjunctival hemorrhage is asymptomatic and occurs following trauma.

Cellulitis manifests following trauma with a deep violet color and marked edema.

Continue to: Standard Tx

 

 

Standard Tx: Antiviral medications

Topical antiviral therapy is the standard treatment for epithelial HSV keratitis, although oral antiviral medications are equally effective. A randomized trial found that using an oral agent in addition to a topical antiviral did not improve outcomes.⁸ A 2015 systematic review found that topical antivirals acyclovir, ganciclovir, brivudine, trifluridine were equally effective in treatment outcome; 90% of patients healed within 2 weeks.⁹

Recurrent ocular HSV-1 infections are treated in the same way as the initial infection. Recurrent infection can be prevented with daily suppressive therapy. In one study, patients who took suppressive therapy (acyclovir 400 mg bid) for 1 year had 19% recurrence of ocular infection vs 32% in the placebo group.¹⁰

It’s always better to consider a diagnosis of primary oral HSV infection than to treat candida and pain with a mixed medication mouthwash.

Prompt Tx is key. If the infection is superficial—involving only the outer layer of the cornea (epithelium)—the eye should heal without scarring with proper treatment. However, if the infection is not promptly treated or if deeper layers are involved, scarring of the cornea may occur. This can lead to vision loss or blindness.

Continue to: A missed opportunity for an earlier diagnosis

 

 

A missed opportunity for an earlier diagnosis

This case highlights the importance of conducting a thorough exam to identify findings that could shift the diagnosis from a simple allergic, viral, or bacterial conjunctivitis. It is always better to consider primary oral HSV infection than resort to a “shotgun approach” of treating candida and pain with an oral mixture. In this case, the ulcers and vesicles on the buccal mucosa, gingiva, and lips were a missed sign of primary HSV infection. Making this diagnosis might have prevented the ocular disease, as the treatment would have been an oral antiviral.

If conjunctivitis is refractory to usual management, the patient must be seen to rule out dangerous eye diagnoses such as HSV keratitis, preseptal or orbital cellulitis, or in the worst case, acute angle closure glaucoma. If there is uncertainty regarding diagnosis, a fluorescein exam is helpful. This simple in-office exam can facilitate a referral to Ophthalmology or the emergency department for a slit-lamp exam and appropriate therapy.

Our patient was started on valacyclovir 1 g bid, trifluridine eyedrops (5×/d), and erythromycin ophthalmic ointment (3×/d), with Ophthalmology follow-up in 1 week.

CORRESPONDENCE
John Spittler, MD, 3055 Roslyn St, Suite 100, Denver, CO 80238; [email protected]

THE CASE

A 24-year-old man with a history of smoking tobacco presented to the hospital with acute-onset chest tightness and dyspnea shortly after smoking cannabis. He was otherwise healthy and hemodynamically stable upon arrival to the emergency department. An electrocardiogram (EKG) was obtained.

THE DIAGNOSIS

The EKG showed ST-segment elevation in the inferolateral leads, consistent with an acute myocardial infarction (AMI) (FIGURE 1). The patient was immediately transported to the cardiac catheterization laboratory, where coronary arteriography demonstrated a normal right coronary artery (FIGURE 2A). Diffuse thrombosis without atherosclerosis was seen throughout the left coronary arteries, including the left main artery, distal left anterior descending (LAD) artery, first diagonal branch of the LAD artery, ostial and proximal left circumflex (LCx) arteries, and first obtuse marginal (OM) branch of the LCx artery (FIGURE 2B).

DISCUSSION

The most common cause of AMI is underlying coronary atherosclerosis;¹ however, AMI may occur due to in-situ thrombosis, thromboembolism, or coronary artery vasospasm, especially due to cocaine or other substance abuse. Occasionally, coronary arteries may be damaged due to viral myocarditis, autoimmune vasculitis, dissection of the ascending aorta, or dissection of a coronary artery, especially during pregnancy and postpartum.^2,3

Cannabis and tobacco increase cardiovascular events

Smoking cannabis has been shown to increase adrenergic activity, resulting in an increased heart rate and elevated arterial pressure.^4,5 These changes may increase myocardial oxygen demand and may result in a decrease in myocardial oxygen supply due to a decrease in the diastolic time.⁶ Smoking cannabis can also increase carboxyhemoglobin levels, which may compromise tissue oxygenation.

Smoking cannabis may predispose individuals to acute myocardial infarction and should be considered in the differential for AMI without coronary atherosclerosis.

The risk for AMI has been shown to increase within the first hour of smoking cannabis.⁵ A few reports have documented cases of acute coronary syndrome following cannabis use; the majority of affected patients presented with chest pain within hours of smoking cannabis and were found to have a thrombus in a coronary artery, which was then treated medically or with percutaneous coronary intervention.⁷ Rare cases of cardiovascular death following cannabis use have also been reported.^7,8

It has been suggested that coronary artery vasospasm may occur from cannabis use, which may precipitate thrombosis; however, this is not well defined.⁹ It is not clear if vasospasm was the inciting factor for thrombus formation in this case, as there was extensive and diffuse thrombus far greater than that expected solely from coronary artery vasospasm.

Continue to: AMI without atherosclerosis? Consider thrombosis

 

 

AMI without atherosclerosis? Consider thrombosis

In-situ coronary thrombosis should be considered in the differential diagnosis of a patient with an AMI without evidence of coronary atherosclerosis. Further, smoking cannabis immediately prior to symptom onset should heighten awareness for potential coronary thrombosis. Lifelong anticoagulation therapy may be indicated in these patients due to the catastrophic nature of the condition and limited data on this particular situation.

What’s recommended. Cessation of cannabis and tobacco smoking is recommended, as the use of these substances may contribute to the development of coronary thrombosis.^3-7,9 A registry of patients with coronary thrombosis without coronary atherosclerosis, especially in states where cannabis is legal, would be useful to gauge the potential increase in such events. In addition, information related to the cardiovascular effects of using alternate routes of drug delivery, such as vaping devices, are limited; therefore, this practice should be closely monitored, as well.

Our patient’s outcome

Thrombus removal. In the cardiac catheterization laboratory, the majority of the thrombus was removed and coronary blood flow was improved using a thrombectomy catheter (FIGURE 2C). Residual thrombus remained in the very distal coronary arteries (FIGURE 2D), so heparin infusion was continued.

Imaging studies. Following the procedure, an echocardiogram demonstrated left ventricular (LV) regional wall motion abnormalities with moderately reduced LV systolic function and an ejection fraction (EF) of 35%. Troponin I levels peaked at 35 ng/mL. No LV apical thrombus or intracardiac defects (eg, patent foramen ovale, atrial septal defect, ventricular septal defect) that might have contributed to thromboembolism or paradoxical embolus were seen on echocardiogram or cardiac magnetic resonance imaging. In addition, ultrasound of the lower extremities did not demonstrate deep venous thrombosis.

Continue to: A toxicology screen

A toxicology screen was positive for tetrahydrocannabinol (THC) and negative for other substances. Hypercoagulable laboratory studies were normal, including anticardiolipin antibody IgG and IgM, factor V Leiden, prothrombin G20210A mutation, thrombin time, antithrombin III, and protein C and S activity. It was therefore believed that the AMI was due to in-situ coronary artery thrombus formation precipitated acutely by smoking cannabis—possibly with an underlying hypercoagulable state, even though no laboratory abnormalities were detected.

A registry of patients with coronary thrombosis without coronary atherosclerosis, especially in states where cannabis is legal, would be useful.

Our patient was discharged on lifelong aspirin 81 mg/d and oral rivaroxaban (maintenance dose of 20 mg/d). Metoprolol succinate 12.5 mg/d and lisinopril 2.5 mg/d were also initiated due to LV systolic dysfunction (and to be used indefinitely). Cannabis and tobacco smoking cessation was strongly emphasized, as both have independently been shown to increase cardiovascular events; the overall effects of using both substances, however, are currently unknown. At 6-month follow-up, the patient was doing well; an echocardiogram demonstrated an improvement in LV systolic function with an LVEF of 45%.

THE TAKEWAY

Coronary thrombosis can result in an AMI, even without underlying coronary atherosclerosis. Smoking cannabis may predispose individuals to in-situ coronary thrombosis and subsequent AMI. Although not often encountered in clinical practice, providers must be aware of this phenomenon in the differential diagnosis for AMI—particularly in young patients without traditional risk factors.

CORRESPONDENCE
Konstantinos Dean Boudoulas, MD, The Ohio State University Davis Lung and Heart Research Institute, 473 W. 12th Avenue, Suite 200, Columbus, Ohio 43210; [email protected]

THE CASE

A 24-year-old man with a history of smoking tobacco presented to the hospital with acute-onset chest tightness and dyspnea shortly after smoking cannabis. He was otherwise healthy and hemodynamically stable upon arrival to the emergency department. An electrocardiogram (EKG) was obtained.

THE DIAGNOSIS

The EKG showed ST-segment elevation in the inferolateral leads, consistent with an acute myocardial infarction (AMI) (FIGURE 1). The patient was immediately transported to the cardiac catheterization laboratory, where coronary arteriography demonstrated a normal right coronary artery (FIGURE 2A). Diffuse thrombosis without atherosclerosis was seen throughout the left coronary arteries, including the left main artery, distal left anterior descending (LAD) artery, first diagonal branch of the LAD artery, ostial and proximal left circumflex (LCx) arteries, and first obtuse marginal (OM) branch of the LCx artery (FIGURE 2B).

DISCUSSION

The most common cause of AMI is underlying coronary atherosclerosis;¹ however, AMI may occur due to in-situ thrombosis, thromboembolism, or coronary artery vasospasm, especially due to cocaine or other substance abuse. Occasionally, coronary arteries may be damaged due to viral myocarditis, autoimmune vasculitis, dissection of the ascending aorta, or dissection of a coronary artery, especially during pregnancy and postpartum.^2,3

Cannabis and tobacco increase cardiovascular events

Smoking cannabis has been shown to increase adrenergic activity, resulting in an increased heart rate and elevated arterial pressure.^4,5 These changes may increase myocardial oxygen demand and may result in a decrease in myocardial oxygen supply due to a decrease in the diastolic time.⁶ Smoking cannabis can also increase carboxyhemoglobin levels, which may compromise tissue oxygenation.

Smoking cannabis may predispose individuals to acute myocardial infarction and should be considered in the differential for AMI without coronary atherosclerosis.

The risk for AMI has been shown to increase within the first hour of smoking cannabis.⁵ A few reports have documented cases of acute coronary syndrome following cannabis use; the majority of affected patients presented with chest pain within hours of smoking cannabis and were found to have a thrombus in a coronary artery, which was then treated medically or with percutaneous coronary intervention.⁷ Rare cases of cardiovascular death following cannabis use have also been reported.^7,8

It has been suggested that coronary artery vasospasm may occur from cannabis use, which may precipitate thrombosis; however, this is not well defined.⁹ It is not clear if vasospasm was the inciting factor for thrombus formation in this case, as there was extensive and diffuse thrombus far greater than that expected solely from coronary artery vasospasm.

Continue to: AMI without atherosclerosis? Consider thrombosis

 

 

AMI without atherosclerosis? Consider thrombosis

In-situ coronary thrombosis should be considered in the differential diagnosis of a patient with an AMI without evidence of coronary atherosclerosis. Further, smoking cannabis immediately prior to symptom onset should heighten awareness for potential coronary thrombosis. Lifelong anticoagulation therapy may be indicated in these patients due to the catastrophic nature of the condition and limited data on this particular situation.

What’s recommended. Cessation of cannabis and tobacco smoking is recommended, as the use of these substances may contribute to the development of coronary thrombosis.^3-7,9 A registry of patients with coronary thrombosis without coronary atherosclerosis, especially in states where cannabis is legal, would be useful to gauge the potential increase in such events. In addition, information related to the cardiovascular effects of using alternate routes of drug delivery, such as vaping devices, are limited; therefore, this practice should be closely monitored, as well.

Our patient’s outcome

Thrombus removal. In the cardiac catheterization laboratory, the majority of the thrombus was removed and coronary blood flow was improved using a thrombectomy catheter (FIGURE 2C). Residual thrombus remained in the very distal coronary arteries (FIGURE 2D), so heparin infusion was continued.

Imaging studies. Following the procedure, an echocardiogram demonstrated left ventricular (LV) regional wall motion abnormalities with moderately reduced LV systolic function and an ejection fraction (EF) of 35%. Troponin I levels peaked at 35 ng/mL. No LV apical thrombus or intracardiac defects (eg, patent foramen ovale, atrial septal defect, ventricular septal defect) that might have contributed to thromboembolism or paradoxical embolus were seen on echocardiogram or cardiac magnetic resonance imaging. In addition, ultrasound of the lower extremities did not demonstrate deep venous thrombosis.

Continue to: A toxicology screen

A toxicology screen was positive for tetrahydrocannabinol (THC) and negative for other substances. Hypercoagulable laboratory studies were normal, including anticardiolipin antibody IgG and IgM, factor V Leiden, prothrombin G20210A mutation, thrombin time, antithrombin III, and protein C and S activity. It was therefore believed that the AMI was due to in-situ coronary artery thrombus formation precipitated acutely by smoking cannabis—possibly with an underlying hypercoagulable state, even though no laboratory abnormalities were detected.

A registry of patients with coronary thrombosis without coronary atherosclerosis, especially in states where cannabis is legal, would be useful.

Our patient was discharged on lifelong aspirin 81 mg/d and oral rivaroxaban (maintenance dose of 20 mg/d). Metoprolol succinate 12.5 mg/d and lisinopril 2.5 mg/d were also initiated due to LV systolic dysfunction (and to be used indefinitely). Cannabis and tobacco smoking cessation was strongly emphasized, as both have independently been shown to increase cardiovascular events; the overall effects of using both substances, however, are currently unknown. At 6-month follow-up, the patient was doing well; an echocardiogram demonstrated an improvement in LV systolic function with an LVEF of 45%.

THE TAKEWAY

Coronary thrombosis can result in an AMI, even without underlying coronary atherosclerosis. Smoking cannabis may predispose individuals to in-situ coronary thrombosis and subsequent AMI. Although not often encountered in clinical practice, providers must be aware of this phenomenon in the differential diagnosis for AMI—particularly in young patients without traditional risk factors.

CORRESPONDENCE
Konstantinos Dean Boudoulas, MD, The Ohio State University Davis Lung and Heart Research Institute, 473 W. 12th Avenue, Suite 200, Columbus, Ohio 43210; [email protected]

THE CASE

A 24-year-old man with a history of smoking tobacco presented to the hospital with acute-onset chest tightness and dyspnea shortly after smoking cannabis. He was otherwise healthy and hemodynamically stable upon arrival to the emergency department. An electrocardiogram (EKG) was obtained.

THE DIAGNOSIS

The EKG showed ST-segment elevation in the inferolateral leads, consistent with an acute myocardial infarction (AMI) (FIGURE 1). The patient was immediately transported to the cardiac catheterization laboratory, where coronary arteriography demonstrated a normal right coronary artery (FIGURE 2A). Diffuse thrombosis without atherosclerosis was seen throughout the left coronary arteries, including the left main artery, distal left anterior descending (LAD) artery, first diagonal branch of the LAD artery, ostial and proximal left circumflex (LCx) arteries, and first obtuse marginal (OM) branch of the LCx artery (FIGURE 2B).