Imaging

WASHINGTON – When performed prior to revascularization, CT angiography almost doubles the likelihood of successful revascularization of chronic total occlusion relative to no CT angiography, according to a meta-analysis.

Because the meta-analysis relied primarily on retrospective data, the conclusion was characterized as hypothesis-generating. But the author, Wael Abuzeid, MD, an interventional cardiologist and assistant professor at Queen’s University, Kingston, Ont., suggested that there are several arguments to be made for pursuing a randomized trial.

Ted Bosworth/Frontline Medical News

[email protected]

SOURCE: Abuzeid W. CRT 18.

WASHINGTON – When performed prior to revascularization, CT angiography almost doubles the likelihood of successful revascularization of chronic total occlusion relative to no CT angiography, according to a meta-analysis.

Because the meta-analysis relied primarily on retrospective data, the conclusion was characterized as hypothesis-generating. But the author, Wael Abuzeid, MD, an interventional cardiologist and assistant professor at Queen’s University, Kingston, Ont., suggested that there are several arguments to be made for pursuing a randomized trial.

Ted Bosworth/Frontline Medical News

[email protected]

SOURCE: Abuzeid W. CRT 18.

WASHINGTON – When performed prior to revascularization, CT angiography almost doubles the likelihood of successful revascularization of chronic total occlusion relative to no CT angiography, according to a meta-analysis.

Because the meta-analysis relied primarily on retrospective data, the conclusion was characterized as hypothesis-generating. But the author, Wael Abuzeid, MD, an interventional cardiologist and assistant professor at Queen’s University, Kingston, Ont., suggested that there are several arguments to be made for pursuing a randomized trial.

Ted Bosworth/Frontline Medical News

[email protected]

SOURCE: Abuzeid W. CRT 18.

A 62-year-old woman with hypertension and type 2 diabetes mellitus has been experiencing shortness of breath on exertion and chest discomfort for 2 months. Her hypertension has been suboptimally controlled, and her most recent hemoglobin A_1c measurement was 7.0%. She has never smoked and has no family history of premature coronary artery disease (CAD). She is otherwise well and walks for 30 minutes 3 times per week. A 12-lead electrocardiogram demonstrated normal sinus rhythm with left bundle branch block. Her physician suspects she has CAD. What testing does this patient need?

LIMITED DATA, GUIDELINES

For clinicians investigating suspected obstructive CAD in patients with left bundle branch block on resting electrocardiography, the data and guidelines are limited regarding the optimal noninvasive tests and how to interpret them.

Here, we present a practical review of the diagnostic utility of exercise stress electrocardiography, exercise stress echocardiography, dobutamine stress echocardiography, nuclear myocardial perfusion imaging, and computed tomographic (CT) angiography for assessing suspected obstructive CAD in patients with resting left bundle branch block.

WHAT IS LEFT BUNDLE BRANCH BLOCK?

In left bundle branch block, as the name implies, electrical conduction along the left bundle branch is blocked or delayed. Ventricular activation therefore begins in the right ventricle and the right side of the interventricular septum.¹ Transseptal activation from the right ventricle to the left ventricle is slow, because it is transmyocardial.¹ Left ventricular basal and posterolateral wall segments become activated last.¹ Due to delay in the onset of left ventricular contraction, ventricular contraction is dyssynchronous. Classically, interventricular septal motion during systole has been described as paradoxical, with anterior septal motion.^2–4

On electrocardiography, the QRS duration is widened (≥ 120 ms), with a distinctive morphology as shown in Figure 1. Left bundle branch block makes it difficult to accurately assess for dynamic ST-segment changes with exercise, rendering exercise stress electrocardiography a suboptimal test for obstructive CAD if left bundle branch block is present.

LEFT BUNDLE BRANCH BLOCK AND RISK OF DEATH

Although left bundle branch block can be an isolated finding, it can also be associated with underlying obstructive CAD⁵ or cardiomyopathy.⁶ When it occurs at rest, the risk of death from a cardiovascular event is 3 to 4 times higher.⁷ However, the exact incidence of significant obstructive CAD in asymptomatic patients with incidentally detected left bundle branch block is unknown.

Acute left bundle branch block accompanying acute myocardial infarction is associated with a high risk of death. Hindman et al,⁸ in a 1978 multicenter study, described 432 patients with acute myocardial infarction and left or right bundle branch block. In the 163 patients who had left bundle branch block, the in-hospital mortality rate was 24% and the 1-year mortality rate was 32%.

Freedman et al⁹ in 1987 reviewed 15,609 patients with chronic CAD who underwent coronary angiography, of whom 522 had left or right bundle branch block. During a follow-up of nearly 5 years, 2,386 patients died. The actuarial probability of death at 2 years in patients with left bundle branch block was more than 5 times that of patients without it (P < .0001).

During 18 years of observation in the Framingham study,¹⁰ 55 participants developed left bundle branch block, at a mean age at onset of 62. Twenty-six (48%) of these participants developed clinically significant CAD or heart failure coincident with or subsequent to the onset of left bundle branch block. Fifty percent of the participants who developed left bundle branch block died of cardiovascular disease within 10 years of its onset.

Exercise stress electrocardiography, although valuable for assessing functional capacity, cannot be used to diagnose obstructive CAD in patients with left bundle branch block.¹¹

EXERCISE STRESS ECHOCARDIOGRAPHY

Exercise stress echocardiography is proven and widely used for assessing myocardial ischemia in patients with suspected obstructive CAD. But the data are limited on its diagnostic utility in patients with left bundle branch block. Until recently, recommendations for its use in this situation were based on only 1 small study.¹²

Peteiro et al¹² in 2000 described 35 patients who underwent exercise stress echocardiography and coronary angiography. Detection of wall-motion abnormalities had high sensitivity (76%), specificity (83%), and diagnostic accuracy (80%).

Of note, 8 (23%) of the patients could not achieve at least 85% of the maximum predicted heart rate, and for them, the study was not diagnostic for ischemia. (Technically, the study is said to be nondiagnostic when the patient fails to achieve the target heart rate of at least 85% of the maximum predicted heart rate.)

Additionally, 18 of the 35 patients—over half—had a decrease in left ventricular ejection fraction in response to exercise. These 18 patients included 12 of the 17 patients with obstructive CAD and 6 of the 18 patients without obstructive CAD.¹² It is unclear whether a significant proportion of these 18 patients would have been otherwise categorized as having a globally abnormal left ventricular contractile response to exercise according to contemporary (2007) reporting standards.¹³

Xu et al^14,15 in 2016 examined the diagnostic utility of exercise stress echocardiography in assessing suspected obstructive CAD in 191 patients with resting left bundle branch block; 17 patients who failed to achieve a heart rate of at least 85% of the age-predicted maximum heart rate were excluded. Of the remaining 174 patients, 82 demonstrated a normal left ventricular contractile response to exercise and 92 had an abnormal response. In the abnormal group, 70 patients had a globally abnormal response, and 22 patients had a regional ischemic response. Of those who had a globally abnormal left ventricular contractile response who subsequently underwent angiography, only 30% were found to have obstructive CAD.

Although the sensitivity of exercise stress echocardiography was high (94%), its specificity and diagnostic accuracy were poor (specificity 21%, diagnostic accuracy 52%).^14,15 These results suggest that for patients with resting left bundle branch block undergoing exercise stress echocardiography, obstructive CAD cannot be reliably diagnosed in those who develop a globally abnormal left ventricular contractile response. Therefore, an alternative imaging strategy should be considered.

DOBUTAMINE STRESS ECHOCARDIOGRAPHY

The evidence base for dobutamine stress echocardiography in patients with left bundle branch block is more robust than that for exercise stress echocardiography.

Geleijnse et al¹ studied 64 patients with left bundle branch block undergoing dobutamine stress echocardiography who also underwent coronary angiography. Dobutamine stress echocardiography was moderately sensitive for detecting anterior and posterior myocardial wall ischemia (60% and 67%, respectively). Its specificity and diagnostic accuracy were high, at 94% and 98%, respectively.

Yanik et al¹⁶ studied 30 patients with left bundle branch block undergoing both dobutamine stress echocardiography and coronary angiography. The sensitivity of dobutamine stress echocardiography for identifying ischemia in the left anterior descending territory was 82%, the specificity was 95%, and the diagnostic accuracy was 90%. For identifying ischemia in the circumflex and right coronary artery territories, the sensitivity was 88%, specificity 96%, and accuracy 93%.

Mairesse et al¹⁷ studied 24 patients with left bundle branch block undergoing dobutamine stress echocardiography, myocardial perfusion tomography, and coronary angiography. Dobutamine stress echocardiography performed well in detecting ischemia in the left anterior descending territory, with a sensitivity of 83%, specificity 92%, and diagnostic accuracy 87%.

Of note, the available data come from very small studies published more than 15 years ago, and pharmacologic stress testing cannot provide the very important prognostic information derived from treadmill testing.

NUCLEAR MYOCARDIAL PERFUSION IMAGING

Exercise nuclear single-photon emission computed tomography (SPECT) myocardial perfusion imaging in patients with left bundle branch block is challenging, due to the development of septal perfusion defects at rest and during exercise in the absence of obstructive disease in the left anterior descending artery (Figure 2).^18,19 Asynchronous contraction of the septum, with resulting compression of the septal arteries, decreased flow demands to the septal region, and attenuation artifacts are possible explanations for this phenomenon.²⁰

Pharmacologic stress has been reported to improve the diagnostic accuracy of SPECT myocardial perfusion imaging.²¹

Biagini et al,²¹ in a meta-analysis of noninvasive techniques for diagnosing CAD in patients with left bundle branch block, found 1,785 patients from 39 studies who underwent nuclear myocardial perfusion imaging (48.8% with exercise, 41.9% with pharmacologic stress). Overall, sensitivity was high for both exercise and pharmacologic stress (92.9% and 88.5%). However, the reported specificity with exercise stress was significantly lower than with pharmacologic stress (23.3% vs 74.2%, P < .01).

Nuclear positron-emission tomography (PET) may further improve the diagnostic utility of nuclear myocardial perfusion imaging in patients with left bundle branch block. In a study of 440 patients with left bundle branch block undergoing myocardial perfusion imaging, 67 underwent PET and 373 underwent SPECT.²² Possible septal perfusion artifacts were significantly less common with PET than with SPECT (1.5% vs 19.3%, P < .001).

CT ANGIOGRAPHY

CT angiography has a high sensitivity and specificity for detecting significant obstructive CAD.^23,24 Machines with 320 detector rows have been reported to have a sensitivity of 94% and specificity of 87% for detecting significant CAD and are not affected by resting left bundle branch block.²⁵

Of note, coronary artery calcification increases in older patients, especially those age 65 and older,²⁶ and this confers a higher likelihood of “bystander” CAD. Significant coronary artery calcification limits the diagnostic accuracy of multidetector cardiac CT. Additionally, the detection of bystander CAD leads to positive findings of uncertain clinical significance.

Exercise stress echocardiography

American College of Cardiology Foundation/American Heart Association guidelines for diagnosis and management of patients with stable ischemic heart disease recommend exercise stress echocardiography for patients with an intermediate to high pretest probability of ischemic heart disease who have an uninterpretable electrocardiogram and at least moderate physical functioning or no disabling comorbidity (class 1 indication, level of evidence B).¹¹

Current American Society of Echocardiography guidelines also support exercise stress echocardiography as an appropriate test for suspected obstructive CAD in patients with resting left bundle branch block.²⁷ However, this recommendation is based on limited data.

Pharmacologic stress nuclear myocardial perfusion imaging

American Society of Nuclear Cardiology guidelines endorse pharmacologic stress nuclear myocardial perfusion imaging using coronary vasodilators for evaluating suspected obstructive CAD in patients with resting left bundle branch block.^28,29

THE POSSIBLE HARMS OF TESTING

Although current guidelines recommend it, recent data show that exercise stress echocardiography has poor specificity and diagnostic accuracy for significant obstructive CAD in patients with resting left bundle branch block. And performing this test in patients with left bundle branch block may result in further downstream investigations.

Based on limited data from a small number of studies published more than 15 years ago, dobutamine stress echocardiography has moderate sensitivity and specificity for significant CAD in patients with resting left bundle branch block. However, this test does not provide functional information about the patient’s exercise performance.

Pharmacologic stress nuclear myocardial perfusion imaging using coronary vasodilators is an appropriate investigation strategy. However, radiation exposure is a limitation.³⁰

CT angiography can assess for significant obstructive CAD in patients with resting left bundle branch block. However, its diagnostic accuracy can be affected by coronary calcification in older patients. Additionally, each scan is associated with a small amount of radiation exposure,³¹ and a small number of patients will have a true contrast allergy.³²

CLINICAL BOTTOM LINE

For patients with typical ischemic symptoms and new left bundle branch block on electrocardiography, specialist cardiology consultation should be sought, with consideration given to proceeding directly to coronary angiography. For stable outpatients, we propose the following diagnostic approach (Figure 3).

Exercise stress echocardiography is recommended by current guidelines, but it cannot reliably detect significant obstructive CAD in patients with resting left bundle branch block—its specificity and diagnostic accuracy are poor.^14,15 Alternative imaging strategies include CT angiography, pharmacologic nuclear myocardial perfusion imaging using coronary vasodilators, and dobutamine stress echocardiography.

For investigating suspected obstructive CAD in patients with resting left bundle branch block, we propose CT angiography as the first-line imaging test for patients under age 65 and pharmacologic stress nuclear myocardial perfusion imaging using coronary vasodilators or dobutamine stress echocardiography for those age 65 and older. For patients who cannot tolerate contrast due to renal impairment or who have a true contrast allergy, pharmacologic nuclear myocardial perfusion imaging using coronary vasodilators and dobutamine stress echocardiography may be used as alternatives.

A 62-year-old woman with hypertension and type 2 diabetes mellitus has been experiencing shortness of breath on exertion and chest discomfort for 2 months. Her hypertension has been suboptimally controlled, and her most recent hemoglobin A_1c measurement was 7.0%. She has never smoked and has no family history of premature coronary artery disease (CAD). She is otherwise well and walks for 30 minutes 3 times per week. A 12-lead electrocardiogram demonstrated normal sinus rhythm with left bundle branch block. Her physician suspects she has CAD. What testing does this patient need?

LIMITED DATA, GUIDELINES

For clinicians investigating suspected obstructive CAD in patients with left bundle branch block on resting electrocardiography, the data and guidelines are limited regarding the optimal noninvasive tests and how to interpret them.

Here, we present a practical review of the diagnostic utility of exercise stress electrocardiography, exercise stress echocardiography, dobutamine stress echocardiography, nuclear myocardial perfusion imaging, and computed tomographic (CT) angiography for assessing suspected obstructive CAD in patients with resting left bundle branch block.

WHAT IS LEFT BUNDLE BRANCH BLOCK?

In left bundle branch block, as the name implies, electrical conduction along the left bundle branch is blocked or delayed. Ventricular activation therefore begins in the right ventricle and the right side of the interventricular septum.¹ Transseptal activation from the right ventricle to the left ventricle is slow, because it is transmyocardial.¹ Left ventricular basal and posterolateral wall segments become activated last.¹ Due to delay in the onset of left ventricular contraction, ventricular contraction is dyssynchronous. Classically, interventricular septal motion during systole has been described as paradoxical, with anterior septal motion.^2–4

On electrocardiography, the QRS duration is widened (≥ 120 ms), with a distinctive morphology as shown in Figure 1. Left bundle branch block makes it difficult to accurately assess for dynamic ST-segment changes with exercise, rendering exercise stress electrocardiography a suboptimal test for obstructive CAD if left bundle branch block is present.

LEFT BUNDLE BRANCH BLOCK AND RISK OF DEATH

Although left bundle branch block can be an isolated finding, it can also be associated with underlying obstructive CAD⁵ or cardiomyopathy.⁶ When it occurs at rest, the risk of death from a cardiovascular event is 3 to 4 times higher.⁷ However, the exact incidence of significant obstructive CAD in asymptomatic patients with incidentally detected left bundle branch block is unknown.

Acute left bundle branch block accompanying acute myocardial infarction is associated with a high risk of death. Hindman et al,⁸ in a 1978 multicenter study, described 432 patients with acute myocardial infarction and left or right bundle branch block. In the 163 patients who had left bundle branch block, the in-hospital mortality rate was 24% and the 1-year mortality rate was 32%.

Freedman et al⁹ in 1987 reviewed 15,609 patients with chronic CAD who underwent coronary angiography, of whom 522 had left or right bundle branch block. During a follow-up of nearly 5 years, 2,386 patients died. The actuarial probability of death at 2 years in patients with left bundle branch block was more than 5 times that of patients without it (P < .0001).

During 18 years of observation in the Framingham study,¹⁰ 55 participants developed left bundle branch block, at a mean age at onset of 62. Twenty-six (48%) of these participants developed clinically significant CAD or heart failure coincident with or subsequent to the onset of left bundle branch block. Fifty percent of the participants who developed left bundle branch block died of cardiovascular disease within 10 years of its onset.

Exercise stress electrocardiography, although valuable for assessing functional capacity, cannot be used to diagnose obstructive CAD in patients with left bundle branch block.¹¹

EXERCISE STRESS ECHOCARDIOGRAPHY

Exercise stress echocardiography is proven and widely used for assessing myocardial ischemia in patients with suspected obstructive CAD. But the data are limited on its diagnostic utility in patients with left bundle branch block. Until recently, recommendations for its use in this situation were based on only 1 small study.¹²

Peteiro et al¹² in 2000 described 35 patients who underwent exercise stress echocardiography and coronary angiography. Detection of wall-motion abnormalities had high sensitivity (76%), specificity (83%), and diagnostic accuracy (80%).

Of note, 8 (23%) of the patients could not achieve at least 85% of the maximum predicted heart rate, and for them, the study was not diagnostic for ischemia. (Technically, the study is said to be nondiagnostic when the patient fails to achieve the target heart rate of at least 85% of the maximum predicted heart rate.)

Additionally, 18 of the 35 patients—over half—had a decrease in left ventricular ejection fraction in response to exercise. These 18 patients included 12 of the 17 patients with obstructive CAD and 6 of the 18 patients without obstructive CAD.¹² It is unclear whether a significant proportion of these 18 patients would have been otherwise categorized as having a globally abnormal left ventricular contractile response to exercise according to contemporary (2007) reporting standards.¹³

Xu et al^14,15 in 2016 examined the diagnostic utility of exercise stress echocardiography in assessing suspected obstructive CAD in 191 patients with resting left bundle branch block; 17 patients who failed to achieve a heart rate of at least 85% of the age-predicted maximum heart rate were excluded. Of the remaining 174 patients, 82 demonstrated a normal left ventricular contractile response to exercise and 92 had an abnormal response. In the abnormal group, 70 patients had a globally abnormal response, and 22 patients had a regional ischemic response. Of those who had a globally abnormal left ventricular contractile response who subsequently underwent angiography, only 30% were found to have obstructive CAD.

Although the sensitivity of exercise stress echocardiography was high (94%), its specificity and diagnostic accuracy were poor (specificity 21%, diagnostic accuracy 52%).^14,15 These results suggest that for patients with resting left bundle branch block undergoing exercise stress echocardiography, obstructive CAD cannot be reliably diagnosed in those who develop a globally abnormal left ventricular contractile response. Therefore, an alternative imaging strategy should be considered.

DOBUTAMINE STRESS ECHOCARDIOGRAPHY

The evidence base for dobutamine stress echocardiography in patients with left bundle branch block is more robust than that for exercise stress echocardiography.

Geleijnse et al¹ studied 64 patients with left bundle branch block undergoing dobutamine stress echocardiography who also underwent coronary angiography. Dobutamine stress echocardiography was moderately sensitive for detecting anterior and posterior myocardial wall ischemia (60% and 67%, respectively). Its specificity and diagnostic accuracy were high, at 94% and 98%, respectively.

Yanik et al¹⁶ studied 30 patients with left bundle branch block undergoing both dobutamine stress echocardiography and coronary angiography. The sensitivity of dobutamine stress echocardiography for identifying ischemia in the left anterior descending territory was 82%, the specificity was 95%, and the diagnostic accuracy was 90%. For identifying ischemia in the circumflex and right coronary artery territories, the sensitivity was 88%, specificity 96%, and accuracy 93%.

Mairesse et al¹⁷ studied 24 patients with left bundle branch block undergoing dobutamine stress echocardiography, myocardial perfusion tomography, and coronary angiography. Dobutamine stress echocardiography performed well in detecting ischemia in the left anterior descending territory, with a sensitivity of 83%, specificity 92%, and diagnostic accuracy 87%.

Of note, the available data come from very small studies published more than 15 years ago, and pharmacologic stress testing cannot provide the very important prognostic information derived from treadmill testing.

NUCLEAR MYOCARDIAL PERFUSION IMAGING

Exercise nuclear single-photon emission computed tomography (SPECT) myocardial perfusion imaging in patients with left bundle branch block is challenging, due to the development of septal perfusion defects at rest and during exercise in the absence of obstructive disease in the left anterior descending artery (Figure 2).^18,19 Asynchronous contraction of the septum, with resulting compression of the septal arteries, decreased flow demands to the septal region, and attenuation artifacts are possible explanations for this phenomenon.²⁰

Pharmacologic stress has been reported to improve the diagnostic accuracy of SPECT myocardial perfusion imaging.²¹

Biagini et al,²¹ in a meta-analysis of noninvasive techniques for diagnosing CAD in patients with left bundle branch block, found 1,785 patients from 39 studies who underwent nuclear myocardial perfusion imaging (48.8% with exercise, 41.9% with pharmacologic stress). Overall, sensitivity was high for both exercise and pharmacologic stress (92.9% and 88.5%). However, the reported specificity with exercise stress was significantly lower than with pharmacologic stress (23.3% vs 74.2%, P < .01).

Nuclear positron-emission tomography (PET) may further improve the diagnostic utility of nuclear myocardial perfusion imaging in patients with left bundle branch block. In a study of 440 patients with left bundle branch block undergoing myocardial perfusion imaging, 67 underwent PET and 373 underwent SPECT.²² Possible septal perfusion artifacts were significantly less common with PET than with SPECT (1.5% vs 19.3%, P < .001).

CT ANGIOGRAPHY

CT angiography has a high sensitivity and specificity for detecting significant obstructive CAD.^23,24 Machines with 320 detector rows have been reported to have a sensitivity of 94% and specificity of 87% for detecting significant CAD and are not affected by resting left bundle branch block.²⁵

Of note, coronary artery calcification increases in older patients, especially those age 65 and older,²⁶ and this confers a higher likelihood of “bystander” CAD. Significant coronary artery calcification limits the diagnostic accuracy of multidetector cardiac CT. Additionally, the detection of bystander CAD leads to positive findings of uncertain clinical significance.

Exercise stress echocardiography

American College of Cardiology Foundation/American Heart Association guidelines for diagnosis and management of patients with stable ischemic heart disease recommend exercise stress echocardiography for patients with an intermediate to high pretest probability of ischemic heart disease who have an uninterpretable electrocardiogram and at least moderate physical functioning or no disabling comorbidity (class 1 indication, level of evidence B).¹¹

Current American Society of Echocardiography guidelines also support exercise stress echocardiography as an appropriate test for suspected obstructive CAD in patients with resting left bundle branch block.²⁷ However, this recommendation is based on limited data.

Pharmacologic stress nuclear myocardial perfusion imaging

American Society of Nuclear Cardiology guidelines endorse pharmacologic stress nuclear myocardial perfusion imaging using coronary vasodilators for evaluating suspected obstructive CAD in patients with resting left bundle branch block.^28,29

THE POSSIBLE HARMS OF TESTING

Although current guidelines recommend it, recent data show that exercise stress echocardiography has poor specificity and diagnostic accuracy for significant obstructive CAD in patients with resting left bundle branch block. And performing this test in patients with left bundle branch block may result in further downstream investigations.

Based on limited data from a small number of studies published more than 15 years ago, dobutamine stress echocardiography has moderate sensitivity and specificity for significant CAD in patients with resting left bundle branch block. However, this test does not provide functional information about the patient’s exercise performance.

Pharmacologic stress nuclear myocardial perfusion imaging using coronary vasodilators is an appropriate investigation strategy. However, radiation exposure is a limitation.³⁰

CT angiography can assess for significant obstructive CAD in patients with resting left bundle branch block. However, its diagnostic accuracy can be affected by coronary calcification in older patients. Additionally, each scan is associated with a small amount of radiation exposure,³¹ and a small number of patients will have a true contrast allergy.³²

CLINICAL BOTTOM LINE

For patients with typical ischemic symptoms and new left bundle branch block on electrocardiography, specialist cardiology consultation should be sought, with consideration given to proceeding directly to coronary angiography. For stable outpatients, we propose the following diagnostic approach (Figure 3).

Exercise stress echocardiography is recommended by current guidelines, but it cannot reliably detect significant obstructive CAD in patients with resting left bundle branch block—its specificity and diagnostic accuracy are poor.^14,15 Alternative imaging strategies include CT angiography, pharmacologic nuclear myocardial perfusion imaging using coronary vasodilators, and dobutamine stress echocardiography.

For investigating suspected obstructive CAD in patients with resting left bundle branch block, we propose CT angiography as the first-line imaging test for patients under age 65 and pharmacologic stress nuclear myocardial perfusion imaging using coronary vasodilators or dobutamine stress echocardiography for those age 65 and older. For patients who cannot tolerate contrast due to renal impairment or who have a true contrast allergy, pharmacologic nuclear myocardial perfusion imaging using coronary vasodilators and dobutamine stress echocardiography may be used as alternatives.

A 62-year-old woman with hypertension and type 2 diabetes mellitus has been experiencing shortness of breath on exertion and chest discomfort for 2 months. Her hypertension has been suboptimally controlled, and her most recent hemoglobin A_1c measurement was 7.0%. She has never smoked and has no family history of premature coronary artery disease (CAD). She is otherwise well and walks for 30 minutes 3 times per week. A 12-lead electrocardiogram demonstrated normal sinus rhythm with left bundle branch block. Her physician suspects she has CAD. What testing does this patient need?

LIMITED DATA, GUIDELINES

For clinicians investigating suspected obstructive CAD in patients with left bundle branch block on resting electrocardiography, the data and guidelines are limited regarding the optimal noninvasive tests and how to interpret them.

Here, we present a practical review of the diagnostic utility of exercise stress electrocardiography, exercise stress echocardiography, dobutamine stress echocardiography, nuclear myocardial perfusion imaging, and computed tomographic (CT) angiography for assessing suspected obstructive CAD in patients with resting left bundle branch block.

WHAT IS LEFT BUNDLE BRANCH BLOCK?

In left bundle branch block, as the name implies, electrical conduction along the left bundle branch is blocked or delayed. Ventricular activation therefore begins in the right ventricle and the right side of the interventricular septum.¹ Transseptal activation from the right ventricle to the left ventricle is slow, because it is transmyocardial.¹ Left ventricular basal and posterolateral wall segments become activated last.¹ Due to delay in the onset of left ventricular contraction, ventricular contraction is dyssynchronous. Classically, interventricular septal motion during systole has been described as paradoxical, with anterior septal motion.^2–4

On electrocardiography, the QRS duration is widened (≥ 120 ms), with a distinctive morphology as shown in Figure 1. Left bundle branch block makes it difficult to accurately assess for dynamic ST-segment changes with exercise, rendering exercise stress electrocardiography a suboptimal test for obstructive CAD if left bundle branch block is present.

LEFT BUNDLE BRANCH BLOCK AND RISK OF DEATH

Although left bundle branch block can be an isolated finding, it can also be associated with underlying obstructive CAD⁵ or cardiomyopathy.⁶ When it occurs at rest, the risk of death from a cardiovascular event is 3 to 4 times higher.⁷ However, the exact incidence of significant obstructive CAD in asymptomatic patients with incidentally detected left bundle branch block is unknown.

Acute left bundle branch block accompanying acute myocardial infarction is associated with a high risk of death. Hindman et al,⁸ in a 1978 multicenter study, described 432 patients with acute myocardial infarction and left or right bundle branch block. In the 163 patients who had left bundle branch block, the in-hospital mortality rate was 24% and the 1-year mortality rate was 32%.

Freedman et al⁹ in 1987 reviewed 15,609 patients with chronic CAD who underwent coronary angiography, of whom 522 had left or right bundle branch block. During a follow-up of nearly 5 years, 2,386 patients died. The actuarial probability of death at 2 years in patients with left bundle branch block was more than 5 times that of patients without it (P < .0001).

During 18 years of observation in the Framingham study,¹⁰ 55 participants developed left bundle branch block, at a mean age at onset of 62. Twenty-six (48%) of these participants developed clinically significant CAD or heart failure coincident with or subsequent to the onset of left bundle branch block. Fifty percent of the participants who developed left bundle branch block died of cardiovascular disease within 10 years of its onset.

Exercise stress electrocardiography, although valuable for assessing functional capacity, cannot be used to diagnose obstructive CAD in patients with left bundle branch block.¹¹

EXERCISE STRESS ECHOCARDIOGRAPHY

Exercise stress echocardiography is proven and widely used for assessing myocardial ischemia in patients with suspected obstructive CAD. But the data are limited on its diagnostic utility in patients with left bundle branch block. Until recently, recommendations for its use in this situation were based on only 1 small study.¹²

Peteiro et al¹² in 2000 described 35 patients who underwent exercise stress echocardiography and coronary angiography. Detection of wall-motion abnormalities had high sensitivity (76%), specificity (83%), and diagnostic accuracy (80%).

Of note, 8 (23%) of the patients could not achieve at least 85% of the maximum predicted heart rate, and for them, the study was not diagnostic for ischemia. (Technically, the study is said to be nondiagnostic when the patient fails to achieve the target heart rate of at least 85% of the maximum predicted heart rate.)

Additionally, 18 of the 35 patients—over half—had a decrease in left ventricular ejection fraction in response to exercise. These 18 patients included 12 of the 17 patients with obstructive CAD and 6 of the 18 patients without obstructive CAD.¹² It is unclear whether a significant proportion of these 18 patients would have been otherwise categorized as having a globally abnormal left ventricular contractile response to exercise according to contemporary (2007) reporting standards.¹³

Xu et al^14,15 in 2016 examined the diagnostic utility of exercise stress echocardiography in assessing suspected obstructive CAD in 191 patients with resting left bundle branch block; 17 patients who failed to achieve a heart rate of at least 85% of the age-predicted maximum heart rate were excluded. Of the remaining 174 patients, 82 demonstrated a normal left ventricular contractile response to exercise and 92 had an abnormal response. In the abnormal group, 70 patients had a globally abnormal response, and 22 patients had a regional ischemic response. Of those who had a globally abnormal left ventricular contractile response who subsequently underwent angiography, only 30% were found to have obstructive CAD.

Although the sensitivity of exercise stress echocardiography was high (94%), its specificity and diagnostic accuracy were poor (specificity 21%, diagnostic accuracy 52%).^14,15 These results suggest that for patients with resting left bundle branch block undergoing exercise stress echocardiography, obstructive CAD cannot be reliably diagnosed in those who develop a globally abnormal left ventricular contractile response. Therefore, an alternative imaging strategy should be considered.

DOBUTAMINE STRESS ECHOCARDIOGRAPHY

The evidence base for dobutamine stress echocardiography in patients with left bundle branch block is more robust than that for exercise stress echocardiography.

Geleijnse et al¹ studied 64 patients with left bundle branch block undergoing dobutamine stress echocardiography who also underwent coronary angiography. Dobutamine stress echocardiography was moderately sensitive for detecting anterior and posterior myocardial wall ischemia (60% and 67%, respectively). Its specificity and diagnostic accuracy were high, at 94% and 98%, respectively.

Yanik et al¹⁶ studied 30 patients with left bundle branch block undergoing both dobutamine stress echocardiography and coronary angiography. The sensitivity of dobutamine stress echocardiography for identifying ischemia in the left anterior descending territory was 82%, the specificity was 95%, and the diagnostic accuracy was 90%. For identifying ischemia in the circumflex and right coronary artery territories, the sensitivity was 88%, specificity 96%, and accuracy 93%.

Mairesse et al¹⁷ studied 24 patients with left bundle branch block undergoing dobutamine stress echocardiography, myocardial perfusion tomography, and coronary angiography. Dobutamine stress echocardiography performed well in detecting ischemia in the left anterior descending territory, with a sensitivity of 83%, specificity 92%, and diagnostic accuracy 87%.

Of note, the available data come from very small studies published more than 15 years ago, and pharmacologic stress testing cannot provide the very important prognostic information derived from treadmill testing.

NUCLEAR MYOCARDIAL PERFUSION IMAGING

Exercise nuclear single-photon emission computed tomography (SPECT) myocardial perfusion imaging in patients with left bundle branch block is challenging, due to the development of septal perfusion defects at rest and during exercise in the absence of obstructive disease in the left anterior descending artery (Figure 2).^18,19 Asynchronous contraction of the septum, with resulting compression of the septal arteries, decreased flow demands to the septal region, and attenuation artifacts are possible explanations for this phenomenon.²⁰

Pharmacologic stress has been reported to improve the diagnostic accuracy of SPECT myocardial perfusion imaging.²¹

Biagini et al,²¹ in a meta-analysis of noninvasive techniques for diagnosing CAD in patients with left bundle branch block, found 1,785 patients from 39 studies who underwent nuclear myocardial perfusion imaging (48.8% with exercise, 41.9% with pharmacologic stress). Overall, sensitivity was high for both exercise and pharmacologic stress (92.9% and 88.5%). However, the reported specificity with exercise stress was significantly lower than with pharmacologic stress (23.3% vs 74.2%, P < .01).

Nuclear positron-emission tomography (PET) may further improve the diagnostic utility of nuclear myocardial perfusion imaging in patients with left bundle branch block. In a study of 440 patients with left bundle branch block undergoing myocardial perfusion imaging, 67 underwent PET and 373 underwent SPECT.²² Possible septal perfusion artifacts were significantly less common with PET than with SPECT (1.5% vs 19.3%, P < .001).

CT ANGIOGRAPHY

CT angiography has a high sensitivity and specificity for detecting significant obstructive CAD.^23,24 Machines with 320 detector rows have been reported to have a sensitivity of 94% and specificity of 87% for detecting significant CAD and are not affected by resting left bundle branch block.²⁵

Of note, coronary artery calcification increases in older patients, especially those age 65 and older,²⁶ and this confers a higher likelihood of “bystander” CAD. Significant coronary artery calcification limits the diagnostic accuracy of multidetector cardiac CT. Additionally, the detection of bystander CAD leads to positive findings of uncertain clinical significance.

Exercise stress echocardiography

American College of Cardiology Foundation/American Heart Association guidelines for diagnosis and management of patients with stable ischemic heart disease recommend exercise stress echocardiography for patients with an intermediate to high pretest probability of ischemic heart disease who have an uninterpretable electrocardiogram and at least moderate physical functioning or no disabling comorbidity (class 1 indication, level of evidence B).¹¹

Current American Society of Echocardiography guidelines also support exercise stress echocardiography as an appropriate test for suspected obstructive CAD in patients with resting left bundle branch block.²⁷ However, this recommendation is based on limited data.

Pharmacologic stress nuclear myocardial perfusion imaging

American Society of Nuclear Cardiology guidelines endorse pharmacologic stress nuclear myocardial perfusion imaging using coronary vasodilators for evaluating suspected obstructive CAD in patients with resting left bundle branch block.^28,29

THE POSSIBLE HARMS OF TESTING

Although current guidelines recommend it, recent data show that exercise stress echocardiography has poor specificity and diagnostic accuracy for significant obstructive CAD in patients with resting left bundle branch block. And performing this test in patients with left bundle branch block may result in further downstream investigations.

Based on limited data from a small number of studies published more than 15 years ago, dobutamine stress echocardiography has moderate sensitivity and specificity for significant CAD in patients with resting left bundle branch block. However, this test does not provide functional information about the patient’s exercise performance.

Pharmacologic stress nuclear myocardial perfusion imaging using coronary vasodilators is an appropriate investigation strategy. However, radiation exposure is a limitation.³⁰

CT angiography can assess for significant obstructive CAD in patients with resting left bundle branch block. However, its diagnostic accuracy can be affected by coronary calcification in older patients. Additionally, each scan is associated with a small amount of radiation exposure,³¹ and a small number of patients will have a true contrast allergy.³²

CLINICAL BOTTOM LINE

For patients with typical ischemic symptoms and new left bundle branch block on electrocardiography, specialist cardiology consultation should be sought, with consideration given to proceeding directly to coronary angiography. For stable outpatients, we propose the following diagnostic approach (Figure 3).

Exercise stress echocardiography is recommended by current guidelines, but it cannot reliably detect significant obstructive CAD in patients with resting left bundle branch block—its specificity and diagnostic accuracy are poor.^14,15 Alternative imaging strategies include CT angiography, pharmacologic nuclear myocardial perfusion imaging using coronary vasodilators, and dobutamine stress echocardiography.

For investigating suspected obstructive CAD in patients with resting left bundle branch block, we propose CT angiography as the first-line imaging test for patients under age 65 and pharmacologic stress nuclear myocardial perfusion imaging using coronary vasodilators or dobutamine stress echocardiography for those age 65 and older. For patients who cannot tolerate contrast due to renal impairment or who have a true contrast allergy, pharmacologic nuclear myocardial perfusion imaging using coronary vasodilators and dobutamine stress echocardiography may be used as alternatives.

A  44-year-old woman was admitted to the  hospital for the second time in 2 months with acute onset of severe abdominal pain. She had a history of cervical cancer treated with total hysterectomy with bilateral salpingo-oophorectomy, chemotherapy, and radiotherapy at age 38.

LONG-TERM EFFECTS OF RADIATION ON THE BLADDER

Urinary ascites from intraperitoneal urine leakage is a rare but clinically important sequel to bladder fistula or bladder wall rupture. Fistula or rupture can be caused by pelvic irradiation, blunt trauma, or surgical procedures, but may also be spontaneous.²

When the total radiation dose to the bladder exceeds 60 Gy, radiation cystitis may occur, leading to bladder fistula.³ Effects of radiation on the bladder are usually seen within 2 to 4 years³ but may occur long after the completion of radiation therapy—10 years² or even 30 to 40 years later.⁴ Therefore, ascites of unknown origin in a patient with a history of pelvic radiation therapy should lead to an evaluation for late radiation cystitis and urinary ascites from bladder rupture.

A  44-year-old woman was admitted to the  hospital for the second time in 2 months with acute onset of severe abdominal pain. She had a history of cervical cancer treated with total hysterectomy with bilateral salpingo-oophorectomy, chemotherapy, and radiotherapy at age 38.

LONG-TERM EFFECTS OF RADIATION ON THE BLADDER

Urinary ascites from intraperitoneal urine leakage is a rare but clinically important sequel to bladder fistula or bladder wall rupture. Fistula or rupture can be caused by pelvic irradiation, blunt trauma, or surgical procedures, but may also be spontaneous.²

When the total radiation dose to the bladder exceeds 60 Gy, radiation cystitis may occur, leading to bladder fistula.³ Effects of radiation on the bladder are usually seen within 2 to 4 years³ but may occur long after the completion of radiation therapy—10 years² or even 30 to 40 years later.⁴ Therefore, ascites of unknown origin in a patient with a history of pelvic radiation therapy should lead to an evaluation for late radiation cystitis and urinary ascites from bladder rupture.

A  44-year-old woman was admitted to the  hospital for the second time in 2 months with acute onset of severe abdominal pain. She had a history of cervical cancer treated with total hysterectomy with bilateral salpingo-oophorectomy, chemotherapy, and radiotherapy at age 38.

LONG-TERM EFFECTS OF RADIATION ON THE BLADDER

Urinary ascites from intraperitoneal urine leakage is a rare but clinically important sequel to bladder fistula or bladder wall rupture. Fistula or rupture can be caused by pelvic irradiation, blunt trauma, or surgical procedures, but may also be spontaneous.²

When the total radiation dose to the bladder exceeds 60 Gy, radiation cystitis may occur, leading to bladder fistula.³ Effects of radiation on the bladder are usually seen within 2 to 4 years³ but may occur long after the completion of radiation therapy—10 years² or even 30 to 40 years later.⁴ Therefore, ascites of unknown origin in a patient with a history of pelvic radiation therapy should lead to an evaluation for late radiation cystitis and urinary ascites from bladder rupture.

Only half of American general rheumatologists and two-thirds of global systemic sclerosis experts routinely request high-resolution CT chest scans for all their newly diagnosed systemic sclerosis patients despite their increased risk of interstitial lung disease, according to survey data from approximately 200 clinicians.

The researchers, led by Elana J. Bernstein, MD, of Columbia University, New York, conducted the survey because of a lack of data on how often rheumatologists order high-resolution CT for their newly diagnosed patients and the absence of clinical practice guidelines that recommend screening for interstitial lung disease (ILD) in systemic sclerosis (SSc).

In a study published in Arthritis & Rheumatology, the researchers surveyed 676 American College of Rheumatology members and 356 global experts on systemic sclerosis; of these, 76 ACR general rheumatologists and 135 SSc experts responded. The use of high-resolution CT varied widely by country or region: 0 of 5 respondents from Australia, 2 of 6 from Canada, 28 of 47 from the United States, 45 of 57 from Europe, 4 of 5 from Asia, and 7 of 7 from Latin America.

The researchers also found little consensus on indications for high-resolution CT in SSc patients. Among the SSc experts who do not routinely obtain screening high-resolution CTs in their SSc patients, 81% said they would request one for dyspnea on exertion, 74% would request one for an abnormal forced vital capacity less than 80% of predicted, and 52% would request one for an abnormal diffusion capacity for carbon monoxide less than 80% predicted.

A significant limitation of the study was the low response rate, and more research is needed on the clinical impact of high-resolution CT screening for ILD in SSc patients, the researchers noted. However, the results highlight the need for a clinical practice guideline to create a more consistent approach to identifying ILD in these patients, they said.

The researchers had no financial conflicts to disclose. Dr. Bernstein was supported by a Rheumatology Research Foundation Scientist Development Award, and two of her colleagues were funded in part by the National Institute of Arthritis and Musculoskeletal and Skin Diseases and the National Heart, Lung, and Blood Institute.

SOURCE: Bernstein E et al. Arthritis Rheumatol. 2018 Feb 9. doi: 10.1002/art.40441.

Only half of American general rheumatologists and two-thirds of global systemic sclerosis experts routinely request high-resolution CT chest scans for all their newly diagnosed systemic sclerosis patients despite their increased risk of interstitial lung disease, according to survey data from approximately 200 clinicians.

The researchers, led by Elana J. Bernstein, MD, of Columbia University, New York, conducted the survey because of a lack of data on how often rheumatologists order high-resolution CT for their newly diagnosed patients and the absence of clinical practice guidelines that recommend screening for interstitial lung disease (ILD) in systemic sclerosis (SSc).

In a study published in Arthritis & Rheumatology, the researchers surveyed 676 American College of Rheumatology members and 356 global experts on systemic sclerosis; of these, 76 ACR general rheumatologists and 135 SSc experts responded. The use of high-resolution CT varied widely by country or region: 0 of 5 respondents from Australia, 2 of 6 from Canada, 28 of 47 from the United States, 45 of 57 from Europe, 4 of 5 from Asia, and 7 of 7 from Latin America.

The researchers also found little consensus on indications for high-resolution CT in SSc patients. Among the SSc experts who do not routinely obtain screening high-resolution CTs in their SSc patients, 81% said they would request one for dyspnea on exertion, 74% would request one for an abnormal forced vital capacity less than 80% of predicted, and 52% would request one for an abnormal diffusion capacity for carbon monoxide less than 80% predicted.

A significant limitation of the study was the low response rate, and more research is needed on the clinical impact of high-resolution CT screening for ILD in SSc patients, the researchers noted. However, the results highlight the need for a clinical practice guideline to create a more consistent approach to identifying ILD in these patients, they said.

The researchers had no financial conflicts to disclose. Dr. Bernstein was supported by a Rheumatology Research Foundation Scientist Development Award, and two of her colleagues were funded in part by the National Institute of Arthritis and Musculoskeletal and Skin Diseases and the National Heart, Lung, and Blood Institute.

SOURCE: Bernstein E et al. Arthritis Rheumatol. 2018 Feb 9. doi: 10.1002/art.40441.

Only half of American general rheumatologists and two-thirds of global systemic sclerosis experts routinely request high-resolution CT chest scans for all their newly diagnosed systemic sclerosis patients despite their increased risk of interstitial lung disease, according to survey data from approximately 200 clinicians.

The researchers, led by Elana J. Bernstein, MD, of Columbia University, New York, conducted the survey because of a lack of data on how often rheumatologists order high-resolution CT for their newly diagnosed patients and the absence of clinical practice guidelines that recommend screening for interstitial lung disease (ILD) in systemic sclerosis (SSc).

In a study published in Arthritis & Rheumatology, the researchers surveyed 676 American College of Rheumatology members and 356 global experts on systemic sclerosis; of these, 76 ACR general rheumatologists and 135 SSc experts responded. The use of high-resolution CT varied widely by country or region: 0 of 5 respondents from Australia, 2 of 6 from Canada, 28 of 47 from the United States, 45 of 57 from Europe, 4 of 5 from Asia, and 7 of 7 from Latin America.

The researchers also found little consensus on indications for high-resolution CT in SSc patients. Among the SSc experts who do not routinely obtain screening high-resolution CTs in their SSc patients, 81% said they would request one for dyspnea on exertion, 74% would request one for an abnormal forced vital capacity less than 80% of predicted, and 52% would request one for an abnormal diffusion capacity for carbon monoxide less than 80% predicted.

A significant limitation of the study was the low response rate, and more research is needed on the clinical impact of high-resolution CT screening for ILD in SSc patients, the researchers noted. However, the results highlight the need for a clinical practice guideline to create a more consistent approach to identifying ILD in these patients, they said.

The researchers had no financial conflicts to disclose. Dr. Bernstein was supported by a Rheumatology Research Foundation Scientist Development Award, and two of her colleagues were funded in part by the National Institute of Arthritis and Musculoskeletal and Skin Diseases and the National Heart, Lung, and Blood Institute.

SOURCE: Bernstein E et al. Arthritis Rheumatol. 2018 Feb 9. doi: 10.1002/art.40441.

ABSTRACT

The use of arthroscopy for purely diagnostic purposes has been largely supplanted by noninvasive technologies, such as magnetic resonance imaging (MRI). The mi-eye^+TM (Trice Medical) technology is a small-bore needle unit for in-office arthroscopy. We conducted a pilot study comparing the mi-eye^+TM unit with MRI, using surgical arthroscopy as a gold-standard reference. We hypothesized that the mi-eye^+TM needle arthroscope, which can be used in an office setting, would be equivalent to MRI for the diagnosis of intra-articular pathology of the knee.

This prospective, multicenter, observational study was approved by the Institutional Review Board. There were 106 patients (53 males, 53 females) in the study. MRIs were interpreted by musculoskeletally trained radiologists. The study was conducted in the operating room using the mi-eye^+TM device. The mi-eye^{+ TM} device findings were compared with the MRI findings within individual pathologies, and a “per-patient” analysis was performed to compare the arthroscopic findings with those of the mi-eye^+TM and the MRI. Additionally, we identified all mi-eye^+TM findings and MRI findings that exactly matched the surgical arthroscopy findings.

The mi-eye^+TM demonstrated complete accuracy of all pathologies for 97 (91.5%) of the 106 patients included in the study, whereas MRI demonstrated complete accuracy for 65 patients (61.3%) (P < .0001). All discrepancies between mi-eye^+TM and arthroscopy were false-negative mi-eye^+TM results, as the mi-eye^+TM did not reveal some aspect of the knee’s pathology for 9 patients. The mi-eye^+TM was more sensitive than MRI in identifying meniscal tears (92.6% vs 77.8%; P = .0035) and more specific in diagnosing these tears (100% vs 41.7%; P < .0001).

The mi-eye^+TM device proved to be more sensitive and specific than MRI for intra-articular findings at time of knee arthroscopy. Certainly there are contraindications to using the mi-eye^+TM, and our results do not obviate the need for MRI, but our study did demonstrate that the mi-eye^+TM needle arthroscope can safely provide excellent visualization of intra-articular knee pathology.

Continue to: Surgical arthroscopy is the gold standard...

Surgical arthroscopy is the gold standard for the diagnosis of intra-articular knee pathologies. Nevertheless, the use of arthroscopy for purely diagnostic purposes has been largely supplanted by noninvasive technologies, such as magnetic resonance imaging (MRI). Although MRI is considered the standard diagnostic tool for acute and chronic soft-tissue injuries of the knee, its use is not without contraindication and some potential inconveniences. Contraindications to MRI are well documented. In terms of inconvenience, MRI usually requires a separate visit followed by another visit to the prescribing physician. In addition, required interpretation by a radiologist may lead to a delay in care and increase in cost.

In the early 1990s, in-office needle arthroscopy was described as a viable means of diagnosing pathologies and obtaining synovial biopsies from the knee.^1-3 Initial results were good, and the procedures had very low complication rates. Nevertheless, in-office arthroscopy of the knee is not yet widely performed, likely given concerns about the technical difficulties of in-office arthroscopy, the potential for patient discomfort, and the cumbersomeness of in-office arthroscopy units. However, significant advances have been made in the resolution capability of small-bore needle arthroscopy, resulting in much less painful procedures. Additionally, the early hardware designs, which mimicked operating room setups using towers, fluid irrigation systems, and larger arthroscopes, have been replaced with small-needle arthroscopes that use syringes for irrigation and tablet computers for visualization (Figures 1A, 1B).  

The mi-eye^+TM technology (Trice Medical) is a small-bore needle unit for in-office arthroscopy with digital optics that does not need an irrigation tower. We conducted a pilot study of the sensitivity and specificity of the mi-eye^+TM unit in comparison with MRI, using surgical arthroscopy as a gold-standard reference. We hypothesized that the mi-eye^+TM needle arthroscope, which can be used in an office setting, would be equivalent to the standard of care (MRI) for the diagnosis of intra-articular pathology of the knee.

METHODS

Central regulatory approval for this prospective, multicenter, observational study was obtained from the Western Institutional Review Board for 3 of the sites, and 1 institution required and was granted internal Institutional Review Board approval.

The study was performed by 4 sports medicine orthopedic surgeons experienced in using the mi-eye^+TM in-office arthroscope. Patients were enrolled from December 2015 through June 2016. Inclusion criteria were an indication for an arthroscopic procedure of the knee based on history, physical examination, and MRI findings. Patients were excluded from the study if there were any contraindications to completing an MRI. Acute hemarthroses of the knee or active systemic infections were also excluded. Once a patient was identified as meeting the criteria for participation, informed consent was obtained. Of the 113 patients who enrolled, 7 did not have a complete study dataset available, leaving 106 patients (53 males, 53 females) in the study. Mean age was 47 years (range, 18-82 years).

Continue to: A test result form was used...

A test result form was used to record mi-eye^+TM, surgical arthroscopy, and MRI results. This form required a “positive” or “negative” result for all of several diagnoses: medial and lateral meniscal tears, intra-articular loose body, osteoarthritis (OA), osteochondritis dissecans (OCD), and tears of the anterior and posterior cruciate ligaments (ACL, PCL). MRI was performed at a variety of imaging facilities, but the images were interpreted by musculoskeletally trained radiologists.

The study was conducted in the operating room. After the patient was appropriately anesthetized, and the extremity prepared and draped, the mi-eye^+TM procedure was performed immediately prior to surgical arthroscopy. A tourniquet was not used. At surgeon discretion, medial, lateral, or both approaches were used with the mi-eye^+TM, and diagnostic arthroscopy was performed. During the procedure, the mi-eye^+TM was advanced into the knee. Once in the synovial compartment, the external 14-gauge needle was retracted, exposing the unit’s optics. Visualization was improved by injecting normal saline through the lure lock in the mi-eye^+TM needle arthroscope. An average of 20 mL of saline was used, though the amount varied with surgeon discretion. Subsequently, the surgeon visualized structures in the knee and documented all findings.

At the end of the mi-eye^+TM procedure, the scheduled surgical arthroscopy was performed. After the surgical procedure, if there were no issues or complications, the patient was discharged from the study. No follow-up was required for the study, as arthroscopic findings served as the conclusive diagnosis for each patient, and no interventions were being studied. There were no complications related to use of the mi-eye^+TM.

The mi-eye^+TM device findings were compared with the MRI findings within individual pathologies, and a “per-patient” analysis was performed to compare the arthroscopic findings with those of the mi-eye^+TM and the MRI. Additionally, we identified all mi-eye^+TM findings and MRI findings that exactly matched the surgical arthroscopy findings. When a test had no false-positive or false-negative findings in comparison with surgical arthroscopy, it was identified as having complete accuracy for all intra-articular knee pathologies. For these methods, the 95% confidence interval was determined based on binomial distribution.

RESULTS

The mi-eye^{+ TM} demonstrated complete accuracy of all pathologies for 97 (91.5%) of the 106 patients included in the study, whereas MRI demonstrated complete accuracy for 65 patients (61.3%) (P < .0001). All discrepancies between mi-eye^+TM and surgical arthroscopy were false-negative mi-eye^+TM results, as the mi-eye^+TM did not reveal some aspect of the knee’s pathology for 9 patients. On the other hand, MRI demonstrated both false-negative and false-positive results, failing to reveal some aspect of the knee’s pathology for 31 patients, and potentially overcalling some aspect of the knee’s pathology among 18 patients.

Continue to: The pathology most frequently...

The pathology most frequently identified in the study was a meniscal tear. The mi-eye^+TM was more sensitive than MRI in identifying meniscal tears (92.6% vs 77.8%; P = .0035) and more specific in diagnosing these tears (100% vs 87.5%; P < .0002). The difference in specificity resulted from the false MRI diagnosis of a meniscal tear among 24 patients, who were found to have no tear by both mi-eye^+TM and surgical arthroscopy.

Table 1. Raw Data of mi-eye^+TM and Magnetic Resonance Imaging Findings

The second most frequent pathology was an intra-articular loose body. The mi-eye^+TM was more sensitive than MRI in identifying loose bodies (86.7% vs 20%; P = .0007). The specificity of the mi-eye^+TM and the specificity of MRI were equivalent in diagnosing loose bodies (100%). Table 1 and Table 2 show the complete set of diagnoses and associated diagnostic profiles.

Table 2. Diagnostic Profiles: Sensitivity and Specificity of mi-eye^+TM and Magnetic Resonance Imaging

^aBold P values are significant. Abbreviations: CI, confidence interval; MRI, magnetic resonance imaging; N/A, not applicable.

DISCUSSION

The overall accuracy of the mi-eye^+TM was superior to that of MRI relative to the arthroscopic gold standard in this pilot study. Other studies have demonstrated the accuracy, feasibility, and cost-efficacy of in-office arthroscopy. However, likely because of the cumbersomeness of in-office arthroscopy equipment and the potential for patient discomfort, the technique is not yet standard in the field. Recent advances in small-bore technology, digital optics, and ergonomics have addressed the difficulties associated with in-office arthroscopy, facilitating a faster and more efficient procedure. Our goal in this study was to evaluate the diagnostic capability of the mi-eye^+TM in-office arthroscopy unit, which features a small bore, digital optics, and functionality without an irrigation tower.

This study of 106 patients demonstrated equivalent or better accuracy of the mi-eye^+TM relative to MRI when compared with the gold standard of surgical arthroscopy. This was not surprising given that both the mi-eye^+TM and surgical arthroscopy are based on direct visualization of intra-articular pathology. The mi-eye^+TM unit identified more meniscal tears, intra-articular loose bodies, ACL tears, and OCD lesions than MRI did, and with enough power to demonstrate statistically significant improved sensitivity for meniscal tears and loose bodies. Furthermore, MRI demonstrated false-positive meniscal tears, ACL tears, OCD lesions, and OA, whereas the mi-eye^+TM did not demonstrate any false-positive results in comparison with surgical arthroscopy. This study demonstrated statistically significant improved specificity of the mi-eye⁺ compared with MRI in the diagnosis of meniscal tears and OA.

There are several limitations to our study. We refer to it as a pilot study because it was performed in a standard operating room. Before taking the technology to an outpatient setting, we wanted to confirm efficacy and safety in an operating room. However, the techniques used in this study are readily transferable to the outpatient clinic setting and to date have been used in more than 2000 cases.

Continue to: The specificity of MRI...

The specificity of MRI for meniscal tears was unexpectedly low compared with previous studies, which may reflect the multi-institution, multi-surgeon, multi-radiologist involvement in MRI interpretation.^4-10 MRI was performed at a variety of institutions without a standardized protocol. This lack of standardization of image capture and interpretation may have contributed to the suboptimal performance of MRI, falsely decreasing the potential ideal specificity for meniscal tears. Although this study may have underestimated the specificity of MRI for meniscal tears, we think the mi-eye^+TM and MRI results reported here reflect the findings of standard practice, without the standardization usually applied in studies. For example, a study of 139 knee MRI reports at 14 different institutions confirmed arthroscopic findings and concluded that 37% of the operations supported by a significant MRI finding were unjustified.¹¹ The authors attributed the rate of false-positive MRI findings to the wide variety of places where patients had their MRIs performed, and the subsequent variation in quality of imaging and MRI reader skill level.¹¹

Before inserting the mi-eye^+TM needle arthroscope, the surgeons had a working diagnosis of the pathology based on their clinical examination and MRI results. Clearly, this introduced a bias. Further studies will be conducted in a prospective, blinded manner to address this limitation.

Although studies of in-office arthroscopy technology date to the 1990s, there is an overall lack of data comparing in-office arthroscopy with MRI. Halbrecht and Jackson² conducted a study of 20 knee patients with both MRI and in-office needle arthroscopy. Overall, MRI was poor in detecting cartilage defects, with sensitivity of 34.6%, using the in-office arthroscopy as the confirmatory diagnosis. Although the authors did not compare in-office diagnoses with surgical arthroscopic findings, they concluded that office arthroscopy is an accurate and cost-efficient alternative to MRI in diagnostic evaluation of knee patients. Xerogeanes and colleagues¹² studied 110 patients in a prospective, blinded, multicenter trial comparing a minimally invasive office-based arthroscopy with MRI, using surgical arthroscopy as the confirmatory diagnosis. They concluded that the office-based arthroscope was statistically equivalent to diagnostic surgical arthroscopy and that it outperformed MRI in helping make accurate diagnoses. The authors applied a cost analysis to their findings and determined that office-based arthroscopy could result in an annual potential savings of $177 million for the healthcare system.¹²

Modern imaging sequences on high-Tesla MRI machines provide excellent visualization. Nevertheless, a significant number of patients do not undergo MRI, owing to time constraints, contraindications, body habitus, or anxiety/claustrophobia. Our study results confirmed that doctors treating such patients now have a viable alternative to help diagnose pathology.

CONCLUSION

The mi-eye^+TM device proved to be more sensitive and specific than MRI for intra-articular findings at the time of knee arthroscopy. Certainly there are contraindications to using the mi-eye^+TM, and our results do not obviate the need for MRI; our study did demonstrate that the mi-eye^+TM needle arthroscope can safely provide excellent visualization of intra-articular knee pathology. More studies of the mi-eye^+TM device in a clinical setting are warranted.

ABSTRACT

The use of arthroscopy for purely diagnostic purposes has been largely supplanted by noninvasive technologies, such as magnetic resonance imaging (MRI). The mi-eye^+TM (Trice Medical) technology is a small-bore needle unit for in-office arthroscopy. We conducted a pilot study comparing the mi-eye^+TM unit with MRI, using surgical arthroscopy as a gold-standard reference. We hypothesized that the mi-eye^+TM needle arthroscope, which can be used in an office setting, would be equivalent to MRI for the diagnosis of intra-articular pathology of the knee.

This prospective, multicenter, observational study was approved by the Institutional Review Board. There were 106 patients (53 males, 53 females) in the study. MRIs were interpreted by musculoskeletally trained radiologists. The study was conducted in the operating room using the mi-eye^+TM device. The mi-eye^{+ TM} device findings were compared with the MRI findings within individual pathologies, and a “per-patient” analysis was performed to compare the arthroscopic findings with those of the mi-eye^+TM and the MRI. Additionally, we identified all mi-eye^+TM findings and MRI findings that exactly matched the surgical arthroscopy findings.

The mi-eye^+TM demonstrated complete accuracy of all pathologies for 97 (91.5%) of the 106 patients included in the study, whereas MRI demonstrated complete accuracy for 65 patients (61.3%) (P < .0001). All discrepancies between mi-eye^+TM and arthroscopy were false-negative mi-eye^+TM results, as the mi-eye^+TM did not reveal some aspect of the knee’s pathology for 9 patients. The mi-eye^+TM was more sensitive than MRI in identifying meniscal tears (92.6% vs 77.8%; P = .0035) and more specific in diagnosing these tears (100% vs 41.7%; P < .0001).

The mi-eye^+TM device proved to be more sensitive and specific than MRI for intra-articular findings at time of knee arthroscopy. Certainly there are contraindications to using the mi-eye^+TM, and our results do not obviate the need for MRI, but our study did demonstrate that the mi-eye^+TM needle arthroscope can safely provide excellent visualization of intra-articular knee pathology.

Continue to: Surgical arthroscopy is the gold standard...

Surgical arthroscopy is the gold standard for the diagnosis of intra-articular knee pathologies. Nevertheless, the use of arthroscopy for purely diagnostic purposes has been largely supplanted by noninvasive technologies, such as magnetic resonance imaging (MRI). Although MRI is considered the standard diagnostic tool for acute and chronic soft-tissue injuries of the knee, its use is not without contraindication and some potential inconveniences. Contraindications to MRI are well documented. In terms of inconvenience, MRI usually requires a separate visit followed by another visit to the prescribing physician. In addition, required interpretation by a radiologist may lead to a delay in care and increase in cost.

In the early 1990s, in-office needle arthroscopy was described as a viable means of diagnosing pathologies and obtaining synovial biopsies from the knee.^1-3 Initial results were good, and the procedures had very low complication rates. Nevertheless, in-office arthroscopy of the knee is not yet widely performed, likely given concerns about the technical difficulties of in-office arthroscopy, the potential for patient discomfort, and the cumbersomeness of in-office arthroscopy units. However, significant advances have been made in the resolution capability of small-bore needle arthroscopy, resulting in much less painful procedures. Additionally, the early hardware designs, which mimicked operating room setups using towers, fluid irrigation systems, and larger arthroscopes, have been replaced with small-needle arthroscopes that use syringes for irrigation and tablet computers for visualization (Figures 1A, 1B).  

The mi-eye^+TM technology (Trice Medical) is a small-bore needle unit for in-office arthroscopy with digital optics that does not need an irrigation tower. We conducted a pilot study of the sensitivity and specificity of the mi-eye^+TM unit in comparison with MRI, using surgical arthroscopy as a gold-standard reference. We hypothesized that the mi-eye^+TM needle arthroscope, which can be used in an office setting, would be equivalent to the standard of care (MRI) for the diagnosis of intra-articular pathology of the knee.

METHODS

Central regulatory approval for this prospective, multicenter, observational study was obtained from the Western Institutional Review Board for 3 of the sites, and 1 institution required and was granted internal Institutional Review Board approval.

The study was performed by 4 sports medicine orthopedic surgeons experienced in using the mi-eye^+TM in-office arthroscope. Patients were enrolled from December 2015 through June 2016. Inclusion criteria were an indication for an arthroscopic procedure of the knee based on history, physical examination, and MRI findings. Patients were excluded from the study if there were any contraindications to completing an MRI. Acute hemarthroses of the knee or active systemic infections were also excluded. Once a patient was identified as meeting the criteria for participation, informed consent was obtained. Of the 113 patients who enrolled, 7 did not have a complete study dataset available, leaving 106 patients (53 males, 53 females) in the study. Mean age was 47 years (range, 18-82 years).

Continue to: A test result form was used...

A test result form was used to record mi-eye^+TM, surgical arthroscopy, and MRI results. This form required a “positive” or “negative” result for all of several diagnoses: medial and lateral meniscal tears, intra-articular loose body, osteoarthritis (OA), osteochondritis dissecans (OCD), and tears of the anterior and posterior cruciate ligaments (ACL, PCL). MRI was performed at a variety of imaging facilities, but the images were interpreted by musculoskeletally trained radiologists.

The study was conducted in the operating room. After the patient was appropriately anesthetized, and the extremity prepared and draped, the mi-eye^+TM procedure was performed immediately prior to surgical arthroscopy. A tourniquet was not used. At surgeon discretion, medial, lateral, or both approaches were used with the mi-eye^+TM, and diagnostic arthroscopy was performed. During the procedure, the mi-eye^+TM was advanced into the knee. Once in the synovial compartment, the external 14-gauge needle was retracted, exposing the unit’s optics. Visualization was improved by injecting normal saline through the lure lock in the mi-eye^+TM needle arthroscope. An average of 20 mL of saline was used, though the amount varied with surgeon discretion. Subsequently, the surgeon visualized structures in the knee and documented all findings.

At the end of the mi-eye^+TM procedure, the scheduled surgical arthroscopy was performed. After the surgical procedure, if there were no issues or complications, the patient was discharged from the study. No follow-up was required for the study, as arthroscopic findings served as the conclusive diagnosis for each patient, and no interventions were being studied. There were no complications related to use of the mi-eye^+TM.

The mi-eye^+TM device findings were compared with the MRI findings within individual pathologies, and a “per-patient” analysis was performed to compare the arthroscopic findings with those of the mi-eye^+TM and the MRI. Additionally, we identified all mi-eye^+TM findings and MRI findings that exactly matched the surgical arthroscopy findings. When a test had no false-positive or false-negative findings in comparison with surgical arthroscopy, it was identified as having complete accuracy for all intra-articular knee pathologies. For these methods, the 95% confidence interval was determined based on binomial distribution.

RESULTS

The mi-eye^{+ TM} demonstrated complete accuracy of all pathologies for 97 (91.5%) of the 106 patients included in the study, whereas MRI demonstrated complete accuracy for 65 patients (61.3%) (P < .0001). All discrepancies between mi-eye^+TM and surgical arthroscopy were false-negative mi-eye^+TM results, as the mi-eye^+TM did not reveal some aspect of the knee’s pathology for 9 patients. On the other hand, MRI demonstrated both false-negative and false-positive results, failing to reveal some aspect of the knee’s pathology for 31 patients, and potentially overcalling some aspect of the knee’s pathology among 18 patients.

Continue to: The pathology most frequently...

The pathology most frequently identified in the study was a meniscal tear. The mi-eye^+TM was more sensitive than MRI in identifying meniscal tears (92.6% vs 77.8%; P = .0035) and more specific in diagnosing these tears (100% vs 87.5%; P < .0002). The difference in specificity resulted from the false MRI diagnosis of a meniscal tear among 24 patients, who were found to have no tear by both mi-eye^+TM and surgical arthroscopy.

Table 1. Raw Data of mi-eye^+TM and Magnetic Resonance Imaging Findings

The second most frequent pathology was an intra-articular loose body. The mi-eye^+TM was more sensitive than MRI in identifying loose bodies (86.7% vs 20%; P = .0007). The specificity of the mi-eye^+TM and the specificity of MRI were equivalent in diagnosing loose bodies (100%). Table 1 and Table 2 show the complete set of diagnoses and associated diagnostic profiles.

Table 2. Diagnostic Profiles: Sensitivity and Specificity of mi-eye^+TM and Magnetic Resonance Imaging

^aBold P values are significant. Abbreviations: CI, confidence interval; MRI, magnetic resonance imaging; N/A, not applicable.

DISCUSSION

The overall accuracy of the mi-eye^+TM was superior to that of MRI relative to the arthroscopic gold standard in this pilot study. Other studies have demonstrated the accuracy, feasibility, and cost-efficacy of in-office arthroscopy. However, likely because of the cumbersomeness of in-office arthroscopy equipment and the potential for patient discomfort, the technique is not yet standard in the field. Recent advances in small-bore technology, digital optics, and ergonomics have addressed the difficulties associated with in-office arthroscopy, facilitating a faster and more efficient procedure. Our goal in this study was to evaluate the diagnostic capability of the mi-eye^+TM in-office arthroscopy unit, which features a small bore, digital optics, and functionality without an irrigation tower.

This study of 106 patients demonstrated equivalent or better accuracy of the mi-eye^+TM relative to MRI when compared with the gold standard of surgical arthroscopy. This was not surprising given that both the mi-eye^+TM and surgical arthroscopy are based on direct visualization of intra-articular pathology. The mi-eye^+TM unit identified more meniscal tears, intra-articular loose bodies, ACL tears, and OCD lesions than MRI did, and with enough power to demonstrate statistically significant improved sensitivity for meniscal tears and loose bodies. Furthermore, MRI demonstrated false-positive meniscal tears, ACL tears, OCD lesions, and OA, whereas the mi-eye^+TM did not demonstrate any false-positive results in comparison with surgical arthroscopy. This study demonstrated statistically significant improved specificity of the mi-eye⁺ compared with MRI in the diagnosis of meniscal tears and OA.

There are several limitations to our study. We refer to it as a pilot study because it was performed in a standard operating room. Before taking the technology to an outpatient setting, we wanted to confirm efficacy and safety in an operating room. However, the techniques used in this study are readily transferable to the outpatient clinic setting and to date have been used in more than 2000 cases.

Continue to: The specificity of MRI...

The specificity of MRI for meniscal tears was unexpectedly low compared with previous studies, which may reflect the multi-institution, multi-surgeon, multi-radiologist involvement in MRI interpretation.^4-10 MRI was performed at a variety of institutions without a standardized protocol. This lack of standardization of image capture and interpretation may have contributed to the suboptimal performance of MRI, falsely decreasing the potential ideal specificity for meniscal tears. Although this study may have underestimated the specificity of MRI for meniscal tears, we think the mi-eye^+TM and MRI results reported here reflect the findings of standard practice, without the standardization usually applied in studies. For example, a study of 139 knee MRI reports at 14 different institutions confirmed arthroscopic findings and concluded that 37% of the operations supported by a significant MRI finding were unjustified.¹¹ The authors attributed the rate of false-positive MRI findings to the wide variety of places where patients had their MRIs performed, and the subsequent variation in quality of imaging and MRI reader skill level.¹¹

Before inserting the mi-eye^+TM needle arthroscope, the surgeons had a working diagnosis of the pathology based on their clinical examination and MRI results. Clearly, this introduced a bias. Further studies will be conducted in a prospective, blinded manner to address this limitation.

Although studies of in-office arthroscopy technology date to the 1990s, there is an overall lack of data comparing in-office arthroscopy with MRI. Halbrecht and Jackson² conducted a study of 20 knee patients with both MRI and in-office needle arthroscopy. Overall, MRI was poor in detecting cartilage defects, with sensitivity of 34.6%, using the in-office arthroscopy as the confirmatory diagnosis. Although the authors did not compare in-office diagnoses with surgical arthroscopic findings, they concluded that office arthroscopy is an accurate and cost-efficient alternative to MRI in diagnostic evaluation of knee patients. Xerogeanes and colleagues¹² studied 110 patients in a prospective, blinded, multicenter trial comparing a minimally invasive office-based arthroscopy with MRI, using surgical arthroscopy as the confirmatory diagnosis. They concluded that the office-based arthroscope was statistically equivalent to diagnostic surgical arthroscopy and that it outperformed MRI in helping make accurate diagnoses. The authors applied a cost analysis to their findings and determined that office-based arthroscopy could result in an annual potential savings of $177 million for the healthcare system.¹²

Modern imaging sequences on high-Tesla MRI machines provide excellent visualization. Nevertheless, a significant number of patients do not undergo MRI, owing to time constraints, contraindications, body habitus, or anxiety/claustrophobia. Our study results confirmed that doctors treating such patients now have a viable alternative to help diagnose pathology.

CONCLUSION

The mi-eye^+TM device proved to be more sensitive and specific than MRI for intra-articular findings at the time of knee arthroscopy. Certainly there are contraindications to using the mi-eye^+TM, and our results do not obviate the need for MRI; our study did demonstrate that the mi-eye^+TM needle arthroscope can safely provide excellent visualization of intra-articular knee pathology. More studies of the mi-eye^+TM device in a clinical setting are warranted.

ABSTRACT

The use of arthroscopy for purely diagnostic purposes has been largely supplanted by noninvasive technologies, such as magnetic resonance imaging (MRI). The mi-eye^+TM (Trice Medical) technology is a small-bore needle unit for in-office arthroscopy. We conducted a pilot study comparing the mi-eye^+TM unit with MRI, using surgical arthroscopy as a gold-standard reference. We hypothesized that the mi-eye^+TM needle arthroscope, which can be used in an office setting, would be equivalent to MRI for the diagnosis of intra-articular pathology of the knee.

This prospective, multicenter, observational study was approved by the Institutional Review Board. There were 106 patients (53 males, 53 females) in the study. MRIs were interpreted by musculoskeletally trained radiologists. The study was conducted in the operating room using the mi-eye^+TM device. The mi-eye^{+ TM} device findings were compared with the MRI findings within individual pathologies, and a “per-patient” analysis was performed to compare the arthroscopic findings with those of the mi-eye^+TM and the MRI. Additionally, we identified all mi-eye^+TM findings and MRI findings that exactly matched the surgical arthroscopy findings.

The mi-eye^+TM demonstrated complete accuracy of all pathologies for 97 (91.5%) of the 106 patients included in the study, whereas MRI demonstrated complete accuracy for 65 patients (61.3%) (P < .0001). All discrepancies between mi-eye^+TM and arthroscopy were false-negative mi-eye^+TM results, as the mi-eye^+TM did not reveal some aspect of the knee’s pathology for 9 patients. The mi-eye^+TM was more sensitive than MRI in identifying meniscal tears (92.6% vs 77.8%; P = .0035) and more specific in diagnosing these tears (100% vs 41.7%; P < .0001).

The mi-eye^+TM device proved to be more sensitive and specific than MRI for intra-articular findings at time of knee arthroscopy. Certainly there are contraindications to using the mi-eye^+TM, and our results do not obviate the need for MRI, but our study did demonstrate that the mi-eye^+TM needle arthroscope can safely provide excellent visualization of intra-articular knee pathology.

Continue to: Surgical arthroscopy is the gold standard...

Surgical arthroscopy is the gold standard for the diagnosis of intra-articular knee pathologies. Nevertheless, the use of arthroscopy for purely diagnostic purposes has been largely supplanted by noninvasive technologies, such as magnetic resonance imaging (MRI). Although MRI is considered the standard diagnostic tool for acute and chronic soft-tissue injuries of the knee, its use is not without contraindication and some potential inconveniences. Contraindications to MRI are well documented. In terms of inconvenience, MRI usually requires a separate visit followed by another visit to the prescribing physician. In addition, required interpretation by a radiologist may lead to a delay in care and increase in cost.

In the early 1990s, in-office needle arthroscopy was described as a viable means of diagnosing pathologies and obtaining synovial biopsies from the knee.^1-3 Initial results were good, and the procedures had very low complication rates. Nevertheless, in-office arthroscopy of the knee is not yet widely performed, likely given concerns about the technical difficulties of in-office arthroscopy, the potential for patient discomfort, and the cumbersomeness of in-office arthroscopy units. However, significant advances have been made in the resolution capability of small-bore needle arthroscopy, resulting in much less painful procedures. Additionally, the early hardware designs, which mimicked operating room setups using towers, fluid irrigation systems, and larger arthroscopes, have been replaced with small-needle arthroscopes that use syringes for irrigation and tablet computers for visualization (Figures 1A, 1B).  

The mi-eye^+TM technology (Trice Medical) is a small-bore needle unit for in-office arthroscopy with digital optics that does not need an irrigation tower. We conducted a pilot study of the sensitivity and specificity of the mi-eye^+TM unit in comparison with MRI, using surgical arthroscopy as a gold-standard reference. We hypothesized that the mi-eye^+TM needle arthroscope, which can be used in an office setting, would be equivalent to the standard of care (MRI) for the diagnosis of intra-articular pathology of the knee.

METHODS

Central regulatory approval for this prospective, multicenter, observational study was obtained from the Western Institutional Review Board for 3 of the sites, and 1 institution required and was granted internal Institutional Review Board approval.

The study was performed by 4 sports medicine orthopedic surgeons experienced in using the mi-eye^+TM in-office arthroscope. Patients were enrolled from December 2015 through June 2016. Inclusion criteria were an indication for an arthroscopic procedure of the knee based on history, physical examination, and MRI findings. Patients were excluded from the study if there were any contraindications to completing an MRI. Acute hemarthroses of the knee or active systemic infections were also excluded. Once a patient was identified as meeting the criteria for participation, informed consent was obtained. Of the 113 patients who enrolled, 7 did not have a complete study dataset available, leaving 106 patients (53 males, 53 females) in the study. Mean age was 47 years (range, 18-82 years).

Continue to: A test result form was used...

A test result form was used to record mi-eye^+TM, surgical arthroscopy, and MRI results. This form required a “positive” or “negative” result for all of several diagnoses: medial and lateral meniscal tears, intra-articular loose body, osteoarthritis (OA), osteochondritis dissecans (OCD), and tears of the anterior and posterior cruciate ligaments (ACL, PCL). MRI was performed at a variety of imaging facilities, but the images were interpreted by musculoskeletally trained radiologists.

The study was conducted in the operating room. After the patient was appropriately anesthetized, and the extremity prepared and draped, the mi-eye^+TM procedure was performed immediately prior to surgical arthroscopy. A tourniquet was not used. At surgeon discretion, medial, lateral, or both approaches were used with the mi-eye^+TM, and diagnostic arthroscopy was performed. During the procedure, the mi-eye^+TM was advanced into the knee. Once in the synovial compartment, the external 14-gauge needle was retracted, exposing the unit’s optics. Visualization was improved by injecting normal saline through the lure lock in the mi-eye^+TM needle arthroscope. An average of 20 mL of saline was used, though the amount varied with surgeon discretion. Subsequently, the surgeon visualized structures in the knee and documented all findings.

At the end of the mi-eye^+TM procedure, the scheduled surgical arthroscopy was performed. After the surgical procedure, if there were no issues or complications, the patient was discharged from the study. No follow-up was required for the study, as arthroscopic findings served as the conclusive diagnosis for each patient, and no interventions were being studied. There were no complications related to use of the mi-eye^+TM.

The mi-eye^+TM device findings were compared with the MRI findings within individual pathologies, and a “per-patient” analysis was performed to compare the arthroscopic findings with those of the mi-eye^+TM and the MRI. Additionally, we identified all mi-eye^+TM findings and MRI findings that exactly matched the surgical arthroscopy findings. When a test had no false-positive or false-negative findings in comparison with surgical arthroscopy, it was identified as having complete accuracy for all intra-articular knee pathologies. For these methods, the 95% confidence interval was determined based on binomial distribution.

RESULTS

The mi-eye^{+ TM} demonstrated complete accuracy of all pathologies for 97 (91.5%) of the 106 patients included in the study, whereas MRI demonstrated complete accuracy for 65 patients (61.3%) (P < .0001). All discrepancies between mi-eye^+TM and surgical arthroscopy were false-negative mi-eye^+TM results, as the mi-eye^+TM did not reveal some aspect of the knee’s pathology for 9 patients. On the other hand, MRI demonstrated both false-negative and false-positive results, failing to reveal some aspect of the knee’s pathology for 31 patients, and potentially overcalling some aspect of the knee’s pathology among 18 patients.

Continue to: The pathology most frequently...

The pathology most frequently identified in the study was a meniscal tear. The mi-eye^+TM was more sensitive than MRI in identifying meniscal tears (92.6% vs 77.8%; P = .0035) and more specific in diagnosing these tears (100% vs 87.5%; P < .0002). The difference in specificity resulted from the false MRI diagnosis of a meniscal tear among 24 patients, who were found to have no tear by both mi-eye^+TM and surgical arthroscopy.

Table 1. Raw Data of mi-eye^+TM and Magnetic Resonance Imaging Findings

The second most frequent pathology was an intra-articular loose body. The mi-eye^+TM was more sensitive than MRI in identifying loose bodies (86.7% vs 20%; P = .0007). The specificity of the mi-eye^+TM and the specificity of MRI were equivalent in diagnosing loose bodies (100%). Table 1 and Table 2 show the complete set of diagnoses and associated diagnostic profiles.

Table 2. Diagnostic Profiles: Sensitivity and Specificity of mi-eye^+TM and Magnetic Resonance Imaging

^aBold P values are significant. Abbreviations: CI, confidence interval; MRI, magnetic resonance imaging; N/A, not applicable.

DISCUSSION

The overall accuracy of the mi-eye^+TM was superior to that of MRI relative to the arthroscopic gold standard in this pilot study. Other studies have demonstrated the accuracy, feasibility, and cost-efficacy of in-office arthroscopy. However, likely because of the cumbersomeness of in-office arthroscopy equipment and the potential for patient discomfort, the technique is not yet standard in the field. Recent advances in small-bore technology, digital optics, and ergonomics have addressed the difficulties associated with in-office arthroscopy, facilitating a faster and more efficient procedure. Our goal in this study was to evaluate the diagnostic capability of the mi-eye^+TM in-office arthroscopy unit, which features a small bore, digital optics, and functionality without an irrigation tower.

This study of 106 patients demonstrated equivalent or better accuracy of the mi-eye^+TM relative to MRI when compared with the gold standard of surgical arthroscopy. This was not surprising given that both the mi-eye^+TM and surgical arthroscopy are based on direct visualization of intra-articular pathology. The mi-eye^+TM unit identified more meniscal tears, intra-articular loose bodies, ACL tears, and OCD lesions than MRI did, and with enough power to demonstrate statistically significant improved sensitivity for meniscal tears and loose bodies. Furthermore, MRI demonstrated false-positive meniscal tears, ACL tears, OCD lesions, and OA, whereas the mi-eye^+TM did not demonstrate any false-positive results in comparison with surgical arthroscopy. This study demonstrated statistically significant improved specificity of the mi-eye⁺ compared with MRI in the diagnosis of meniscal tears and OA.

There are several limitations to our study. We refer to it as a pilot study because it was performed in a standard operating room. Before taking the technology to an outpatient setting, we wanted to confirm efficacy and safety in an operating room. However, the techniques used in this study are readily transferable to the outpatient clinic setting and to date have been used in more than 2000 cases.

Continue to: The specificity of MRI...

The specificity of MRI for meniscal tears was unexpectedly low compared with previous studies, which may reflect the multi-institution, multi-surgeon, multi-radiologist involvement in MRI interpretation.^4-10 MRI was performed at a variety of institutions without a standardized protocol. This lack of standardization of image capture and interpretation may have contributed to the suboptimal performance of MRI, falsely decreasing the potential ideal specificity for meniscal tears. Although this study may have underestimated the specificity of MRI for meniscal tears, we think the mi-eye^+TM and MRI results reported here reflect the findings of standard practice, without the standardization usually applied in studies. For example, a study of 139 knee MRI reports at 14 different institutions confirmed arthroscopic findings and concluded that 37% of the operations supported by a significant MRI finding were unjustified.¹¹ The authors attributed the rate of false-positive MRI findings to the wide variety of places where patients had their MRIs performed, and the subsequent variation in quality of imaging and MRI reader skill level.¹¹

Before inserting the mi-eye^+TM needle arthroscope, the surgeons had a working diagnosis of the pathology based on their clinical examination and MRI results. Clearly, this introduced a bias. Further studies will be conducted in a prospective, blinded manner to address this limitation.

Although studies of in-office arthroscopy technology date to the 1990s, there is an overall lack of data comparing in-office arthroscopy with MRI. Halbrecht and Jackson² conducted a study of 20 knee patients with both MRI and in-office needle arthroscopy. Overall, MRI was poor in detecting cartilage defects, with sensitivity of 34.6%, using the in-office arthroscopy as the confirmatory diagnosis. Although the authors did not compare in-office diagnoses with surgical arthroscopic findings, they concluded that office arthroscopy is an accurate and cost-efficient alternative to MRI in diagnostic evaluation of knee patients. Xerogeanes and colleagues¹² studied 110 patients in a prospective, blinded, multicenter trial comparing a minimally invasive office-based arthroscopy with MRI, using surgical arthroscopy as the confirmatory diagnosis. They concluded that the office-based arthroscope was statistically equivalent to diagnostic surgical arthroscopy and that it outperformed MRI in helping make accurate diagnoses. The authors applied a cost analysis to their findings and determined that office-based arthroscopy could result in an annual potential savings of $177 million for the healthcare system.¹²

Modern imaging sequences on high-Tesla MRI machines provide excellent visualization. Nevertheless, a significant number of patients do not undergo MRI, owing to time constraints, contraindications, body habitus, or anxiety/claustrophobia. Our study results confirmed that doctors treating such patients now have a viable alternative to help diagnose pathology.

CONCLUSION

The mi-eye^+TM device proved to be more sensitive and specific than MRI for intra-articular findings at the time of knee arthroscopy. Certainly there are contraindications to using the mi-eye^+TM, and our results do not obviate the need for MRI; our study did demonstrate that the mi-eye^+TM needle arthroscope can safely provide excellent visualization of intra-articular knee pathology. More studies of the mi-eye^+TM device in a clinical setting are warranted.

LOS ANGELES – The benefits of mechanical thrombectomy observed in the DAWN trial for patients with acute ischemic stroke and a mismatch between core imaging and clinical presentation out to 24 hours appear to apply regardless of whether their eligibility is determined by CT perfusion or diffusion-weighted magnetic resonance imaging, according to a subanalysis of the trial data.

Diffusion-weighted magnetic resonance imaging (DW-MRI) is considered the gold standard, but it is not as widely available as CT perfusion (CTP) and previous studies have shown that MR is associated with longer times between stroke onset and treatment randomization. “Though MR was originally preferred in DAWN, it was pretty clear that CT perfusion was going to need to be employed in the trial as well,” Cathy Sila, MD, said during her presentation of the results of the subanalysis at the International Stroke Conference 2018, sponsored by the American Heart Association.

The research sought to determine if the two imaging methods perform similarly. CTP is more readily available, but it has some issues. In patients with severe heart failure, a severe proximal stenosis, or a contralateral severe stenosis, the technique may struggle to accurately image the core infarct, which has led some to wonder if the outcomes would be as good using CTP as selection criteria. “In our institution, we’ve had this conversation very frequently,” said Dr. Sila, who is a vascular neurologist and the director of the University Hospitals Systems stroke program in Cleveland.

To be eligible for DAWN, the core infarct had to correspond to at least a 30% decrease in regional blood flow in the CTP map, or an apparent diffusion coefficient of less than 620 on DW-MRI.

The researchers included all 206 patients in the DAWN study (N Engl J Med. 2018;378:11-21), separating them into DW-MRI or CTP groups based on which imaging method was used to randomize them during the trial. There were no statistically significant differences in any of the baseline characteristics between the two imaging groups.

The 26 sites participating in DAWN had clear differences in their preferences for imaging techniques; 19 exclusively used CTP, 4 used only DW-MRI, and 3 sites used a combination of both imaging methods.

There were no statistically significant differences between the two groups in any of the measured clinical outcomes, including neurologic deterioration in hospital (22.8% with CTP vs. 15.7% with DW-MRII, P = .286), symptomatic intracranial hemorrhage (4.1% with CTP vs. 4.8% with DW-MRI, P = 1.000), or death related to stroke (19.5% with CTP vs. 13.3% with DW-MRI, P = .263). Outcomes at 90 days proved to be similar between CTP and DW-MRI for achieving functional independence (29.3% vs. 34.9%, respectively; P = .445) and utility-weighted modified Rankin Scale scores (4.2 vs. 4.9, respectively; P = .172).

Multivariate analyses showed that 90-day functional independence was predicted by thrombectomy treatment, age, blood glucose level, baseline National Institutes of Health Stroke Scale score, and core lab ASPECTS (Alberta Stroke Program Early CT Score), but not the method of imaging.

“The efficacy and safety of mechanical thrombectomy for patients meeting those clinical mismatch criteria at 6-24 hours were comparable whether the small core infarcts were measured by diffusion imaging or cerebral blood flow imaging. I believe that future clinical trials aiming to extend the eligibility outside of this prespecified population should include both imaging modalities to determine whether these results are generalizable,” Dr. Sila said.

The DAWN study was funded by Stryker Neurovascular. Dr. Sila has reported receiving honoraria from Medtronic.

SOURCE: Sila C et al. ISC 2018, abstract LB11.

LOS ANGELES – The benefits of mechanical thrombectomy observed in the DAWN trial for patients with acute ischemic stroke and a mismatch between core imaging and clinical presentation out to 24 hours appear to apply regardless of whether their eligibility is determined by CT perfusion or diffusion-weighted magnetic resonance imaging, according to a subanalysis of the trial data.

Diffusion-weighted magnetic resonance imaging (DW-MRI) is considered the gold standard, but it is not as widely available as CT perfusion (CTP) and previous studies have shown that MR is associated with longer times between stroke onset and treatment randomization. “Though MR was originally preferred in DAWN, it was pretty clear that CT perfusion was going to need to be employed in the trial as well,” Cathy Sila, MD, said during her presentation of the results of the subanalysis at the International Stroke Conference 2018, sponsored by the American Heart Association.

The research sought to determine if the two imaging methods perform similarly. CTP is more readily available, but it has some issues. In patients with severe heart failure, a severe proximal stenosis, or a contralateral severe stenosis, the technique may struggle to accurately image the core infarct, which has led some to wonder if the outcomes would be as good using CTP as selection criteria. “In our institution, we’ve had this conversation very frequently,” said Dr. Sila, who is a vascular neurologist and the director of the University Hospitals Systems stroke program in Cleveland.

To be eligible for DAWN, the core infarct had to correspond to at least a 30% decrease in regional blood flow in the CTP map, or an apparent diffusion coefficient of less than 620 on DW-MRI.

The researchers included all 206 patients in the DAWN study (N Engl J Med. 2018;378:11-21), separating them into DW-MRI or CTP groups based on which imaging method was used to randomize them during the trial. There were no statistically significant differences in any of the baseline characteristics between the two imaging groups.

The 26 sites participating in DAWN had clear differences in their preferences for imaging techniques; 19 exclusively used CTP, 4 used only DW-MRI, and 3 sites used a combination of both imaging methods.

There were no statistically significant differences between the two groups in any of the measured clinical outcomes, including neurologic deterioration in hospital (22.8% with CTP vs. 15.7% with DW-MRII, P = .286), symptomatic intracranial hemorrhage (4.1% with CTP vs. 4.8% with DW-MRI, P = 1.000), or death related to stroke (19.5% with CTP vs. 13.3% with DW-MRI, P = .263). Outcomes at 90 days proved to be similar between CTP and DW-MRI for achieving functional independence (29.3% vs. 34.9%, respectively; P = .445) and utility-weighted modified Rankin Scale scores (4.2 vs. 4.9, respectively; P = .172).

Multivariate analyses showed that 90-day functional independence was predicted by thrombectomy treatment, age, blood glucose level, baseline National Institutes of Health Stroke Scale score, and core lab ASPECTS (Alberta Stroke Program Early CT Score), but not the method of imaging.

“The efficacy and safety of mechanical thrombectomy for patients meeting those clinical mismatch criteria at 6-24 hours were comparable whether the small core infarcts were measured by diffusion imaging or cerebral blood flow imaging. I believe that future clinical trials aiming to extend the eligibility outside of this prespecified population should include both imaging modalities to determine whether these results are generalizable,” Dr. Sila said.

The DAWN study was funded by Stryker Neurovascular. Dr. Sila has reported receiving honoraria from Medtronic.

SOURCE: Sila C et al. ISC 2018, abstract LB11.

LOS ANGELES – The benefits of mechanical thrombectomy observed in the DAWN trial for patients with acute ischemic stroke and a mismatch between core imaging and clinical presentation out to 24 hours appear to apply regardless of whether their eligibility is determined by CT perfusion or diffusion-weighted magnetic resonance imaging, according to a subanalysis of the trial data.

Diffusion-weighted magnetic resonance imaging (DW-MRI) is considered the gold standard, but it is not as widely available as CT perfusion (CTP) and previous studies have shown that MR is associated with longer times between stroke onset and treatment randomization. “Though MR was originally preferred in DAWN, it was pretty clear that CT perfusion was going to need to be employed in the trial as well,” Cathy Sila, MD, said during her presentation of the results of the subanalysis at the International Stroke Conference 2018, sponsored by the American Heart Association.

The research sought to determine if the two imaging methods perform similarly. CTP is more readily available, but it has some issues. In patients with severe heart failure, a severe proximal stenosis, or a contralateral severe stenosis, the technique may struggle to accurately image the core infarct, which has led some to wonder if the outcomes would be as good using CTP as selection criteria. “In our institution, we’ve had this conversation very frequently,” said Dr. Sila, who is a vascular neurologist and the director of the University Hospitals Systems stroke program in Cleveland.

To be eligible for DAWN, the core infarct had to correspond to at least a 30% decrease in regional blood flow in the CTP map, or an apparent diffusion coefficient of less than 620 on DW-MRI.

The researchers included all 206 patients in the DAWN study (N Engl J Med. 2018;378:11-21), separating them into DW-MRI or CTP groups based on which imaging method was used to randomize them during the trial. There were no statistically significant differences in any of the baseline characteristics between the two imaging groups.

The 26 sites participating in DAWN had clear differences in their preferences for imaging techniques; 19 exclusively used CTP, 4 used only DW-MRI, and 3 sites used a combination of both imaging methods.

There were no statistically significant differences between the two groups in any of the measured clinical outcomes, including neurologic deterioration in hospital (22.8% with CTP vs. 15.7% with DW-MRII, P = .286), symptomatic intracranial hemorrhage (4.1% with CTP vs. 4.8% with DW-MRI, P = 1.000), or death related to stroke (19.5% with CTP vs. 13.3% with DW-MRI, P = .263). Outcomes at 90 days proved to be similar between CTP and DW-MRI for achieving functional independence (29.3% vs. 34.9%, respectively; P = .445) and utility-weighted modified Rankin Scale scores (4.2 vs. 4.9, respectively; P = .172).

Multivariate analyses showed that 90-day functional independence was predicted by thrombectomy treatment, age, blood glucose level, baseline National Institutes of Health Stroke Scale score, and core lab ASPECTS (Alberta Stroke Program Early CT Score), but not the method of imaging.

“The efficacy and safety of mechanical thrombectomy for patients meeting those clinical mismatch criteria at 6-24 hours were comparable whether the small core infarcts were measured by diffusion imaging or cerebral blood flow imaging. I believe that future clinical trials aiming to extend the eligibility outside of this prespecified population should include both imaging modalities to determine whether these results are generalizable,” Dr. Sila said.

The DAWN study was funded by Stryker Neurovascular. Dr. Sila has reported receiving honoraria from Medtronic.

SOURCE: Sila C et al. ISC 2018, abstract LB11.

A 66-year-old man presented to the hospital with 3 days of nausea, vomiting, and abdominal pain. He had come to the emergency department several times during this period, but the cause of his symptoms had not been determined.

The patient was successfully treated with urgent right hemicolectomy.

THE CHILAIDITI SIGN AND SYNDROME

The Chilaiditi sign is an infrequent anomaly found incidentally on chest or abdominal radiography as a colonic interposition between the liver and right hemidiaphragm.¹ It is often asymptomatic but is sometimes accompanied by nausea, vomiting, abdominal pain, and constipation, ie, Chilaiditi syndrome.

Generally, after conservative treatment with fasting and pain control, symptoms may subside and follow-up should be sufficient. However, nasogastric decompression and laxatives are occasionally needed and are often effective in patients with Chilaiditi syndrome. Urgent abdominal surgery is indicated for patients with symptoms of volvulus of the colon, stomach, or small intestine.²

DISTINGUISHING CHARACTERISTICS

The Chilaiditi sign is often confused with pneumoperitoneum, which usually requires urgent abdominal surgery. But the presence of haustration or valvulae conniventes (folds in the small bowel mucosa) in the hepatodiaphragmatic space helps distinguish between intraluminal gas and free air. If the patient presents with abdominal pain without signs of peritonitis, and if imaging indicates the Chilaiditi sign, then supplementary imaging (eg, decubitus radiography, chest CT, abdominal CT) is recommended to make the definitive diagnosis and to avoid unnecessary surgery.

Gas under the diaphragm on standing chest radiography without signs of peritonitis may also be seen after laparotomy and after scuba diving as well as in cases of biliary enteric fistula, incompetent sphincter of Oddi, gallstone ileus, and pneumatosis cystoides intestinalis. The incidence rate of the Chilaiditi sign detected by radiography is between 0.025% and 0.28%.³

PREDISPOSING FACTORS

The cause of the Chilaiditi sign remains unknown. Predisposing factors can be categorized as diaphragmatic (diaphragmatic thinning, phrenic nerve injury, expanded thoracic cavity), intestinal (megacolon, increased intra-abdominal pressure), and hepatic (hepatic atrophy, cirrhosis, ascites).

In healthy people, Chilaiditi syndrome is usually attributed to a congenital abnormal lengthening of the colon or to undue looseness of ligaments of the colon and liver.

Recognizing the Chilaiditi sign is particularly important in patients scheduled to undergo a percutaneous transhepatic procedure or colonoscopic examination, as these procedures increase the risk of perforation.

A 66-year-old man presented to the hospital with 3 days of nausea, vomiting, and abdominal pain. He had come to the emergency department several times during this period, but the cause of his symptoms had not been determined.

The patient was successfully treated with urgent right hemicolectomy.

THE CHILAIDITI SIGN AND SYNDROME

The Chilaiditi sign is an infrequent anomaly found incidentally on chest or abdominal radiography as a colonic interposition between the liver and right hemidiaphragm.¹ It is often asymptomatic but is sometimes accompanied by nausea, vomiting, abdominal pain, and constipation, ie, Chilaiditi syndrome.

Generally, after conservative treatment with fasting and pain control, symptoms may subside and follow-up should be sufficient. However, nasogastric decompression and laxatives are occasionally needed and are often effective in patients with Chilaiditi syndrome. Urgent abdominal surgery is indicated for patients with symptoms of volvulus of the colon, stomach, or small intestine.²

DISTINGUISHING CHARACTERISTICS

The Chilaiditi sign is often confused with pneumoperitoneum, which usually requires urgent abdominal surgery. But the presence of haustration or valvulae conniventes (folds in the small bowel mucosa) in the hepatodiaphragmatic space helps distinguish between intraluminal gas and free air. If the patient presents with abdominal pain without signs of peritonitis, and if imaging indicates the Chilaiditi sign, then supplementary imaging (eg, decubitus radiography, chest CT, abdominal CT) is recommended to make the definitive diagnosis and to avoid unnecessary surgery.

Gas under the diaphragm on standing chest radiography without signs of peritonitis may also be seen after laparotomy and after scuba diving as well as in cases of biliary enteric fistula, incompetent sphincter of Oddi, gallstone ileus, and pneumatosis cystoides intestinalis. The incidence rate of the Chilaiditi sign detected by radiography is between 0.025% and 0.28%.³

PREDISPOSING FACTORS

The cause of the Chilaiditi sign remains unknown. Predisposing factors can be categorized as diaphragmatic (diaphragmatic thinning, phrenic nerve injury, expanded thoracic cavity), intestinal (megacolon, increased intra-abdominal pressure), and hepatic (hepatic atrophy, cirrhosis, ascites).

In healthy people, Chilaiditi syndrome is usually attributed to a congenital abnormal lengthening of the colon or to undue looseness of ligaments of the colon and liver.

Recognizing the Chilaiditi sign is particularly important in patients scheduled to undergo a percutaneous transhepatic procedure or colonoscopic examination, as these procedures increase the risk of perforation.

A 66-year-old man presented to the hospital with 3 days of nausea, vomiting, and abdominal pain. He had come to the emergency department several times during this period, but the cause of his symptoms had not been determined.

The patient was successfully treated with urgent right hemicolectomy.

THE CHILAIDITI SIGN AND SYNDROME

The Chilaiditi sign is an infrequent anomaly found incidentally on chest or abdominal radiography as a colonic interposition between the liver and right hemidiaphragm.¹ It is often asymptomatic but is sometimes accompanied by nausea, vomiting, abdominal pain, and constipation, ie, Chilaiditi syndrome.

Generally, after conservative treatment with fasting and pain control, symptoms may subside and follow-up should be sufficient. However, nasogastric decompression and laxatives are occasionally needed and are often effective in patients with Chilaiditi syndrome. Urgent abdominal surgery is indicated for patients with symptoms of volvulus of the colon, stomach, or small intestine.²

DISTINGUISHING CHARACTERISTICS

The Chilaiditi sign is often confused with pneumoperitoneum, which usually requires urgent abdominal surgery. But the presence of haustration or valvulae conniventes (folds in the small bowel mucosa) in the hepatodiaphragmatic space helps distinguish between intraluminal gas and free air. If the patient presents with abdominal pain without signs of peritonitis, and if imaging indicates the Chilaiditi sign, then supplementary imaging (eg, decubitus radiography, chest CT, abdominal CT) is recommended to make the definitive diagnosis and to avoid unnecessary surgery.

Gas under the diaphragm on standing chest radiography without signs of peritonitis may also be seen after laparotomy and after scuba diving as well as in cases of biliary enteric fistula, incompetent sphincter of Oddi, gallstone ileus, and pneumatosis cystoides intestinalis. The incidence rate of the Chilaiditi sign detected by radiography is between 0.025% and 0.28%.³

PREDISPOSING FACTORS

The cause of the Chilaiditi sign remains unknown. Predisposing factors can be categorized as diaphragmatic (diaphragmatic thinning, phrenic nerve injury, expanded thoracic cavity), intestinal (megacolon, increased intra-abdominal pressure), and hepatic (hepatic atrophy, cirrhosis, ascites).

In healthy people, Chilaiditi syndrome is usually attributed to a congenital abnormal lengthening of the colon or to undue looseness of ligaments of the colon and liver.

Recognizing the Chilaiditi sign is particularly important in patients scheduled to undergo a percutaneous transhepatic procedure or colonoscopic examination, as these procedures increase the risk of perforation.

A 75-year-old man presented to the emergency department for evaluation of abdominal pain. He had stage 3 chronic obstructive pulmonary disease (COPD), with a forced expiratory volume in 1 second of 33%.

PREVIOUS HOSPITALIZATION

Aside from his COPD, he had been healthy until 1 month earlier, when he had been hospitalized because of shortness of breath and chest pressure with exertion. His troponin T level had been elevated, peaking at 0.117 ng/mL (reference range 0–0.029).

Left heart catheterization had shown no significant coronary artery disease. A myocardial bridge of the distal left anterior descending coronary artery had been seen, so that the artery appeared to be narrowed by 50% to 60% with ventricular contraction. But this was not thought to have been the cause of his presentation.

On discharge, he required oxygen 4 L/min by nasal cannula. Previously, he had not needed supplemental oxygen.

CURRENT PRESENTATION

The patient described persistent and severe periumbilical abdominal pain during the previous day. It was not associated with eating, and he denied diarrhea, constipation, hematemesis, hematochezia, bright red blood per rectum, or melena. He continued to describe persistent shortness of breath and pleuritic chest pain. His vital signs were as follows:

• Heart rate 104 beats per minute
• Respiratory rate 16 to 20 breaths per minute
• Blood pressure 101–142/62–84 mm Hg
• Oxygen saturation 78% on room air.

His laboratory findings on presentation are shown in Table 1, and his electrocardiogram is shown in Figure 1.

WHAT DOES HIS ELECTROCARDIOGRAM SHOW?

1. Which of the following is the most accurate description of this patient’s electrocardiogram?

• Sinus tachycardia, peaked P waves (P pulmonale) in lead II, and T-wave inversions in the right precordial leads
• Sinus tachycardia and left bundle branch block
• Sinus tachycardia and poor R-wave progression
• Sinus tachycardia and ST elevation in the precordial leads

Our patient’s electrocardiogram shows sinus tachycardia, P pulmonale, T-wave inversion in the right precordial leads (V₁–V₃), and biphasic T waves in lead V_4,, which suggest right ventricular strain.

The rhythm most commonly seen in patients with pulmonary embolism is sinus tachycardia, followed by nonspecific ST-segment or T-wave abnormalities. In one series of patients with acute pulmonary embolism, the classic findings of P pulmonale, right ventricular hypertrophy, right axis deviation, and right bundle branch block were rare (< 6%).¹ Thus, these classic findings are not sensitive for the diagnosis of pulmonary embolism, and their absence does not rule it out.

Further studies for our patient

Transthoracic echocardiography was performed to look for evidence of right ventricular strain secondary to the pulmonary embolism.

2. Which of the following findings on transthoracic echocardiography would not suggest acute pulmonary embolism?

• Midright ventricular wall hypokinesis with apical sparing
• Severe tricuspid regurgitation
• Left ventricular dilation
• Lack of respiratory variation of the inferior vena cava
• Septal wall motion toward the left ventricle

Left ventricular dilation does not suggest acute pulmonary embolism. Echocardiograms of patients with acute submassive pulmonary embolism typically show evidence of right ventricular strain, such as the other entities listed above (midright ventricular hypokinesis with apical sparing, severe tricuspid regurgitation, lack of respiratory variation of the inferior vena cava, and septal wall motion toward the left ventricle).

The degree of right ventricular dysfunction is related to the extent of acute pulmonary vascular occlusion and aids in risk-stratification of patients with acute pulmonary embolism. Midright ventricular wall hypokinesis with apical sparing has been termed the McConnell sign.²

In our patient, transthoracic echocardiography showed:

• Normal left ventricular ejection fraction
• Mild diastolic dysfunction
• Right ventricular dilation with moderately decreased right ventricular systolic function and apical sparing
• Right ventricular systolic pressure 54 mm Hg, consistent with moderate pulmonary hypertension
• Right atrial pressure 10 mm Hg
• No inspiratory collapse of a dilated inferior vena cava
• Mild tricuspid valve regurgitation.

CLASSIFICATION OF ACUTE PULMONARY EMBOLISM

3. Given the above information, how would you classify the patient’s pulmonary embolism?

• Massive
• Submassive
• Low-risk
• Clinically stable

The patient’s pulmonary embolism is submassive.

Historically, the classification of pulmonary embolism was determined by the angiographic thrombus burden. However, this has limited utility because clinical factors (eg, hypotension on initial presentation) have been shown to be better predictors of short-term mortality risk.³

Our patient is characterized as having a submassive pulmonary embolism based on elevated biomarkers (troponin T, N-terminal pro-B-type natriuretic peptide) and right ventricular dysfunction in the absence of hypotension.

ULTRASONOGRAPHY FOR DIAGNOSIS OF DEEP VEIN THROMBOSIS

Venous duplex ultrasonography has become the standard for diagnosis of lower extremity deep vein thrombosis. However, its quality and diagnostic accuracy depend on the skill of the person performing the examination. It is further limited by certain patient characteristics, including severe obesity, edema, and wounds and dressings at the site being examined.⁵

Our patient underwent duplex ultrasonography of the lower extremities, which demonstrated acute proximal and calf deep vein thrombosis in the right femoral, popliteal, and peroneal veins and no deep vein thrombosis in the left leg.

Multiple models exist to estimate the risk of complications in patients with acute pulmonary embolism.

The Bova score⁶ is based on the following factors:

• Systolic blood pressure 90–100 mm Hg (2 points) (patients with systolic blood pressure lower than 90 mm Hg were excluded from the study from which this score was derived)
• Cardiac troponin elevation (2 points)
• Right ventricular dysfunction on echocardiography or computed tomography (2 points)
• Heart rate 100 beats/min or greater (1 point).

A total score of 0, 1, or 2 (stage I) denotes low risk, 3 or 4 points (stage II) intermediate risk, and more than 4 points (stage III) high risk.

The PESI score (Pulmonary Embolism Severity Index)⁷ is based on:

• Age (1 point per year)
• Sex (10 points for being male)
• Heart rate 110 per minute or greater (20 points)
• Cancer (30 points)
• Heart failure (10 points)
• Chronic lung disease (10 points)
• Systolic blood pressure less than 100 mm Hg (30 points)
• Respiratory rate at least 30 per minute (20 points)
• Temperature less than 36ºC (20 points)
• Altered mental status (60 points)
• Arterial oxygen saturation less than 90% (20 points).

The total score is broken down into 5 classes: I (< 65 points), II (65–85), III (86–105), IV (106–125), and V (> 126). Classes I and II are low risk, and the higher ones are high risk.

The simplified PESI score⁸ was developed to more rapidly risk-stratify patients and has been found to be similar to the PESI score in prognostic accuracy. Patients get 1 point for each of the following:

• Age over 80
• Cancer
• Chronic cardiopulmonary disease (heart failure or chronic lung disease)
• Heart rate 110 per minute or greater
• Systolic blood pressure less than 100 mm Hg
• Arterial oxygen saturation less than 90%.

A total score of 0 is low risk; anything higher is high risk.

Back to our patient

Our patient had proximal and calf deep vein thrombosis of the right leg, bilateral submassive pulmonary emboli with associated biomarker elevation and right ventricular dysfunction, and left renal artery thrombosis with infarction. Using the PESI score, his risk of death in the next 30 days was 13.7% and his 30-day risk of a complicated course was 27%. Using the Bova score, his 30-day risk of death was 15.5% and his 30-day risk of a complicated course was 29.2%.^6,7

Notably, the patient’s right ventricular function had also been impaired on the echocardiogram performed during his admission 1 month previously. On transthoracic echocardiography during the current admission, the patient was found to have a similar degree of right ventricular dysfunction. This finding, along with the oxygen requirement that developed during the earlier admission, suggested that his pulmonary embolism may have been subacute and that the diagnosis may have been missed during the earlier hospital stay.

The patient was treated with unfractionated heparin. After the hospital’s multidisciplinary pulmonary embolism response team discussed and weighed the above factors, they recommended to not pursue thrombolytic therapy or inferior vena cava filter placement.

Of note, the patient’s pulses in the left lower extremity continued to be weak but palpable, and the left leg was cooler to touch than the right leg.

ASSESSING PERIPHERAL ARTERY DISEASE

4. How should the finding of weak pulses in this patient’s left leg be initially investigated?

• Computed tomographic angiography with runoff
• Ankle-brachial indices with pulse-volume recordings
• Arterial duplex ultrasonography
• Magnetic resonance angiography of the lower extremities

The ankle-brachial index is the initial diagnostic test for assessment of pulse abnormalities and for diagnosis of lower-extremity peripheral artery disease. It is calculated by dividing the higher of the ankle systolic pressures (posterior tibial or dorsalis pedis) by the higher of the 2 brachial pressures (left or right).⁹ Normal values are between 1.00 and 1.40.

Ankle-brachial indices in our patient

Our patient underwent measurement of his brachial, dorsalis pedis, and posterior tibial artery systolic pressures using blood pressure cuffs and continuous-wave Doppler. Ankle pulse-volume recordings were also obtained.

Given the patient’s poor renal function and concern for acute renal infarction, we thought it best to avoid iodinated or gadolinium contrast, such as with magnetic resonance or computed tomographic angiography.

Segmental leg pressures and pulse-volume recordings can be performed to help localize the level of arterial disease in the extremities, but were not done in this case because of the extensive deep vein thrombosis in the right leg.^10,11

Arterial ultrasonography in our patient

Arterial duplex ultrasonography was performed to help determine the location of arterial disease. It showed patent arteries in the right leg. In the left lower extremity there was slow, monophasic blood flow in the distal superficial femoral artery. The popliteal artery was occluded. The posterior tibial artery was occluded at the origin, with reconstitution distally. The peroneal artery was occluded throughout. The anterior tibial artery was patent throughout. The ultrasonographic findings were thought to be suspicious for arterial thromboembolism.

5. Given that the patient had both arterial thrombosis (renal artery, lower-extremity arteries) and venous thromboembolism (deep vein thrombosis and pulmonary embolism), which of the following would be included in the differential diagnosis?

• Antiphospholipid antibody syndrome
• Protein C or protein S deficiency
• Malignancy
• Paradoxical embolization
• Factor V Leiden mutation

Correct answers include antiphospholipid antibody syndrome, malignancy, and paradoxical embolization.

The differential diagnosis for concomitant venous and arterial thrombosis is broad,¹² and includes the following:

• Structural factors: patent foramen ovale, popliteal artery aneurysm
• Malignancy
• Inflammatory diseases: Behçet disease, Buerger disease, inflammatory bowel disease, antiphospholipid antibody syndrome, elevated lipoprotein(a), elevated homocysteine
• Hematologic diseases: myelodysplastic syndrome, disseminated intravascular coagulation, paroxysmal nocturnal hemoglobinuria, heparin-induced thrombocytopenia.

Traditional risk factors for venous thromboembolism include protein C deficiency, protein S deficiency, factor V Leiden mutation, the prothrombin G20210A gene mutation, and others. These are relatively minor risk factors for venous thrombosis and do not pose a risk for arterial thrombosis.¹² In contrast, antiphospholipid antibody syndrome and malignancy pose a risk for both venous and arterial thrombosis. Paradoxical embolism is a mechanism by which arterial thrombosis (emboli) can develop in the setting of existing venous thrombosis.¹²

Our patient underwent testing for antiphospholipid antibodies and lupus anticoagulant, and he was encouraged to undergo age-appropriate cancer screening as an outpatient.¹²

ANTIPHOSPHOLIPID ANTIBODY SYNDROME

Antiphospholipid antibody syndrome is defined by both clinical and laboratory criteria. Clinical symptoms include vascular thrombosis (arterial, venous, or both) and pregnancy-related complications.¹³

Laboratory criteria require the presence of antiphospholipid antibodies or lupus anticoagulant. These must be confirmed with repeat testing in 12 weeks. Antiphospholipid antibodies are detected by an enzyme-linked immunosorbent assay; laboratory assessment for the presence of lupus anticoagulant is a stepwise process and relies on 4 criteria:

• There should be prolongation of a phospholipid-dependent clotting test (eg, activated partial thromboplastin time, dilute Russell viper venom time test).
• There must be evidence of an inhibitory activity with mixing study.
• The inhibitor must exhibit phospholipid dependence; that is, with more phospholipid there is shortening of clotting time.
• Specific inhibitors must be excluded, including factor VIII and anticoagulant drugs such as heparin.^14–17

From Houghton DE, Moll S. Antiphospholipid antibodies. Vasc Med 2017; 22:545–550.

Clinically, one should consider antiphospholipid antibody syndrome in patients who have arterial thrombosis, a history of pregnancy morbidity, or unexplained prolongation of activated partial thromboplastin time.¹³

Antiphospholipid antibodies may be present in up to a quarter of patients with venous thromboembolism, but it is persistent positivity of antibody assays that is associated with increased future risk of venous thromboembolism.¹⁹ Of note, the risk of venous thromboembolism in patients with confirmed antiphospholipid antibody syndrome is 10 times higher than in the general population.²⁰

ANTIPHOSPHOLIPID ANTIBODIES ARE NOT ALL THE SAME

6. Which of the following antiphospholipid antibodies have not been associated with an increased thrombotic risk?

• Anti-beta-2-glycoprotein I IgG
• Lupus anticoagulant
• Antiphosphatidylserine
• Anticardiolipin IgM
• Anticardiolipin IgG

The correct answer is antiphosphatidylserine.¹⁵

Antiphospholipid antibodies are directed against a portion of select plasma proteins that are uncovered upon phospholipid binding. While lupus anticoagulant, anti-beta-2-glycoprotein I, and anticardiolipin antibodies are associated with thrombosis, antiprothrombin antibodies (including antiprothrombin and antiphosphatidylserine antibodies) are not.^15,21

Patent foramen ovale, a communication between the right and left atrium in the interatrial septum, is associated with an increased risk of paradoxical embolization. The prevalence of patent foramen ovale is estimated to be 27% to 29% in the general population.²² Noncerebral systemic paradoxical embolism occurs less frequently than cerebral embolism, accounting for approximately 5% to 10% of paradoxical emboli.²²

To evaluate for patent foramen ovale, transthoracic echocardiography is performed with a bubble (agitated saline contrast) study to assess for interatrial shunting. Transesophageal echocardiography or transcranial Doppler bubble studies may also be performed.

Although patent foramen ovale is most commonly associated with cerebral embolism, peripheral emboli can occur. Some research suggests that this may be a more common cause of arterial thromboembolism in younger patients. There have also been reports of other sites of systemic embolization, including the renal artery.¹²

Back to our patient

Initial antiphospholipid antibody testing was positive for lupus anticoagulant. Anticardiolipin and anti-beta-2-glycoprotein I antibodies were not detected.

Transesophageal echocardiography revealed a patent foramen ovale with a highly mobile atrial septum (atrial septal aneurysm).

The patient was treated with intravenous unfractionated heparin with bridging to warfarin with a target international normalized ratio (INR) of 2 to 3. His renal artery infarction and his lower-extremity arterial thromboembolic event were conservatively managed. His respiratory status improved, and he no longer required supplemental oxygen. His creatinine peaked at 1.7 mg/dL during his admission and improved to 1.2 mg/dL before he was discharged.

At follow-up, repeat echocardiography showed that his right ventricular systolic pressure had improved (decreased) to 37 mm Hg from 54 mm Hg. Repeat confirmatory testing was positive for lupus anticoagulant 12 weeks later. He has been maintained on warfarin with an INR goal of 2 to 3 as well as low-dose aspirin with plans for long-term anticoagulation. We decided to keep the patient on anticoagulation indefinitely with warfarin; he was not a candidate for a direct oral anticoagulant, given limited data on the use of these agents in the setting of lupus anticoagulant and antiphospholipid antibody syndrome.

SUMMARY OF CASE

In summary, this patient was a 75-year-old man with COPD who presented with abdominal pain. He was noted to have a left renal infarction, extensive unprovoked lower-extremity deep vein thrombosis with pulmonary emboli, and lower limb arterial thromboembolism.

He also had an underlying hypercoagulable state—antiphospholipid antibody syndrome—that predisposed him to both arterial and venous thrombosis. He was ultimately found to have a patent foramen ovale, which further increased the risk of arterial thrombosis by facilitating paradoxical embolization of venous thrombi. It is not certain whether the renal infarction and leg artery thrombi were due to paradoxical embolism or to in situ thrombosis, but we believe that it was most likely paradoxical embolization.        

A 75-year-old man presented to the emergency department for evaluation of abdominal pain. He had stage 3 chronic obstructive pulmonary disease (COPD), with a forced expiratory volume in 1 second of 33%.

PREVIOUS HOSPITALIZATION

Aside from his COPD, he had been healthy until 1 month earlier, when he had been hospitalized because of shortness of breath and chest pressure with exertion. His troponin T level had been elevated, peaking at 0.117 ng/mL (reference range 0–0.029).

Left heart catheterization had shown no significant coronary artery disease. A myocardial bridge of the distal left anterior descending coronary artery had been seen, so that the artery appeared to be narrowed by 50% to 60% with ventricular contraction. But this was not thought to have been the cause of his presentation.

On discharge, he required oxygen 4 L/min by nasal cannula. Previously, he had not needed supplemental oxygen.

CURRENT PRESENTATION

The patient described persistent and severe periumbilical abdominal pain during the previous day. It was not associated with eating, and he denied diarrhea, constipation, hematemesis, hematochezia, bright red blood per rectum, or melena. He continued to describe persistent shortness of breath and pleuritic chest pain. His vital signs were as follows:

• Heart rate 104 beats per minute
• Respiratory rate 16 to 20 breaths per minute
• Blood pressure 101–142/62–84 mm Hg
• Oxygen saturation 78% on room air.

His laboratory findings on presentation are shown in Table 1, and his electrocardiogram is shown in Figure 1.

WHAT DOES HIS ELECTROCARDIOGRAM SHOW?

1. Which of the following is the most accurate description of this patient’s electrocardiogram?

• Sinus tachycardia, peaked P waves (P pulmonale) in lead II, and T-wave inversions in the right precordial leads
• Sinus tachycardia and left bundle branch block
• Sinus tachycardia and poor R-wave progression
• Sinus tachycardia and ST elevation in the precordial leads

Our patient’s electrocardiogram shows sinus tachycardia, P pulmonale, T-wave inversion in the right precordial leads (V₁–V₃), and biphasic T waves in lead V_4,, which suggest right ventricular strain.

The rhythm most commonly seen in patients with pulmonary embolism is sinus tachycardia, followed by nonspecific ST-segment or T-wave abnormalities. In one series of patients with acute pulmonary embolism, the classic findings of P pulmonale, right ventricular hypertrophy, right axis deviation, and right bundle branch block were rare (< 6%).¹ Thus, these classic findings are not sensitive for the diagnosis of pulmonary embolism, and their absence does not rule it out.

Further studies for our patient

Transthoracic echocardiography was performed to look for evidence of right ventricular strain secondary to the pulmonary embolism.

2. Which of the following findings on transthoracic echocardiography would not suggest acute pulmonary embolism?

• Midright ventricular wall hypokinesis with apical sparing
• Severe tricuspid regurgitation
• Left ventricular dilation
• Lack of respiratory variation of the inferior vena cava
• Septal wall motion toward the left ventricle

Left ventricular dilation does not suggest acute pulmonary embolism. Echocardiograms of patients with acute submassive pulmonary embolism typically show evidence of right ventricular strain, such as the other entities listed above (midright ventricular hypokinesis with apical sparing, severe tricuspid regurgitation, lack of respiratory variation of the inferior vena cava, and septal wall motion toward the left ventricle).

The degree of right ventricular dysfunction is related to the extent of acute pulmonary vascular occlusion and aids in risk-stratification of patients with acute pulmonary embolism. Midright ventricular wall hypokinesis with apical sparing has been termed the McConnell sign.²

In our patient, transthoracic echocardiography showed:

• Normal left ventricular ejection fraction
• Mild diastolic dysfunction
• Right ventricular dilation with moderately decreased right ventricular systolic function and apical sparing
• Right ventricular systolic pressure 54 mm Hg, consistent with moderate pulmonary hypertension
• Right atrial pressure 10 mm Hg
• No inspiratory collapse of a dilated inferior vena cava
• Mild tricuspid valve regurgitation.

CLASSIFICATION OF ACUTE PULMONARY EMBOLISM

3. Given the above information, how would you classify the patient’s pulmonary embolism?

• Massive
• Submassive
• Low-risk
• Clinically stable

The patient’s pulmonary embolism is submassive.

Historically, the classification of pulmonary embolism was determined by the angiographic thrombus burden. However, this has limited utility because clinical factors (eg, hypotension on initial presentation) have been shown to be better predictors of short-term mortality risk.³

Our patient is characterized as having a submassive pulmonary embolism based on elevated biomarkers (troponin T, N-terminal pro-B-type natriuretic peptide) and right ventricular dysfunction in the absence of hypotension.

ULTRASONOGRAPHY FOR DIAGNOSIS OF DEEP VEIN THROMBOSIS

Venous duplex ultrasonography has become the standard for diagnosis of lower extremity deep vein thrombosis. However, its quality and diagnostic accuracy depend on the skill of the person performing the examination. It is further limited by certain patient characteristics, including severe obesity, edema, and wounds and dressings at the site being examined.⁵

Our patient underwent duplex ultrasonography of the lower extremities, which demonstrated acute proximal and calf deep vein thrombosis in the right femoral, popliteal, and peroneal veins and no deep vein thrombosis in the left leg.

Multiple models exist to estimate the risk of complications in patients with acute pulmonary embolism.

The Bova score⁶ is based on the following factors:

• Systolic blood pressure 90–100 mm Hg (2 points) (patients with systolic blood pressure lower than 90 mm Hg were excluded from the study from which this score was derived)
• Cardiac troponin elevation (2 points)
• Right ventricular dysfunction on echocardiography or computed tomography (2 points)
• Heart rate 100 beats/min or greater (1 point).

A total score of 0, 1, or 2 (stage I) denotes low risk, 3 or 4 points (stage II) intermediate risk, and more than 4 points (stage III) high risk.

The PESI score (Pulmonary Embolism Severity Index)⁷ is based on:

• Age (1 point per year)
• Sex (10 points for being male)
• Heart rate 110 per minute or greater (20 points)
• Cancer (30 points)
• Heart failure (10 points)
• Chronic lung disease (10 points)
• Systolic blood pressure less than 100 mm Hg (30 points)
• Respiratory rate at least 30 per minute (20 points)
• Temperature less than 36ºC (20 points)
• Altered mental status (60 points)
• Arterial oxygen saturation less than 90% (20 points).

The total score is broken down into 5 classes: I (< 65 points), II (65–85), III (86–105), IV (106–125), and V (> 126). Classes I and II are low risk, and the higher ones are high risk.

The simplified PESI score⁸ was developed to more rapidly risk-stratify patients and has been found to be similar to the PESI score in prognostic accuracy. Patients get 1 point for each of the following:

• Age over 80
• Cancer
• Chronic cardiopulmonary disease (heart failure or chronic lung disease)
• Heart rate 110 per minute or greater
• Systolic blood pressure less than 100 mm Hg
• Arterial oxygen saturation less than 90%.

A total score of 0 is low risk; anything higher is high risk.

Back to our patient

Our patient had proximal and calf deep vein thrombosis of the right leg, bilateral submassive pulmonary emboli with associated biomarker elevation and right ventricular dysfunction, and left renal artery thrombosis with infarction. Using the PESI score, his risk of death in the next 30 days was 13.7% and his 30-day risk of a complicated course was 27%. Using the Bova score, his 30-day risk of death was 15.5% and his 30-day risk of a complicated course was 29.2%.^6,7

Notably, the patient’s right ventricular function had also been impaired on the echocardiogram performed during his admission 1 month previously. On transthoracic echocardiography during the current admission, the patient was found to have a similar degree of right ventricular dysfunction. This finding, along with the oxygen requirement that developed during the earlier admission, suggested that his pulmonary embolism may have been subacute and that the diagnosis may have been missed during the earlier hospital stay.

The patient was treated with unfractionated heparin. After the hospital’s multidisciplinary pulmonary embolism response team discussed and weighed the above factors, they recommended to not pursue thrombolytic therapy or inferior vena cava filter placement.

Of note, the patient’s pulses in the left lower extremity continued to be weak but palpable, and the left leg was cooler to touch than the right leg.

ASSESSING PERIPHERAL ARTERY DISEASE

4. How should the finding of weak pulses in this patient’s left leg be initially investigated?

• Computed tomographic angiography with runoff
• Ankle-brachial indices with pulse-volume recordings
• Arterial duplex ultrasonography
• Magnetic resonance angiography of the lower extremities

The ankle-brachial index is the initial diagnostic test for assessment of pulse abnormalities and for diagnosis of lower-extremity peripheral artery disease. It is calculated by dividing the higher of the ankle systolic pressures (posterior tibial or dorsalis pedis) by the higher of the 2 brachial pressures (left or right).⁹ Normal values are between 1.00 and 1.40.

Ankle-brachial indices in our patient

Our patient underwent measurement of his brachial, dorsalis pedis, and posterior tibial artery systolic pressures using blood pressure cuffs and continuous-wave Doppler. Ankle pulse-volume recordings were also obtained.

Given the patient’s poor renal function and concern for acute renal infarction, we thought it best to avoid iodinated or gadolinium contrast, such as with magnetic resonance or computed tomographic angiography.

Segmental leg pressures and pulse-volume recordings can be performed to help localize the level of arterial disease in the extremities, but were not done in this case because of the extensive deep vein thrombosis in the right leg.^10,11

Arterial ultrasonography in our patient

Arterial duplex ultrasonography was performed to help determine the location of arterial disease. It showed patent arteries in the right leg. In the left lower extremity there was slow, monophasic blood flow in the distal superficial femoral artery. The popliteal artery was occluded. The posterior tibial artery was occluded at the origin, with reconstitution distally. The peroneal artery was occluded throughout. The anterior tibial artery was patent throughout. The ultrasonographic findings were thought to be suspicious for arterial thromboembolism.

5. Given that the patient had both arterial thrombosis (renal artery, lower-extremity arteries) and venous thromboembolism (deep vein thrombosis and pulmonary embolism), which of the following would be included in the differential diagnosis?

• Antiphospholipid antibody syndrome
• Protein C or protein S deficiency
• Malignancy
• Paradoxical embolization
• Factor V Leiden mutation

Correct answers include antiphospholipid antibody syndrome, malignancy, and paradoxical embolization.

The differential diagnosis for concomitant venous and arterial thrombosis is broad,¹² and includes the following:

• Structural factors: patent foramen ovale, popliteal artery aneurysm
• Malignancy
• Inflammatory diseases: Behçet disease, Buerger disease, inflammatory bowel disease, antiphospholipid antibody syndrome, elevated lipoprotein(a), elevated homocysteine
• Hematologic diseases: myelodysplastic syndrome, disseminated intravascular coagulation, paroxysmal nocturnal hemoglobinuria, heparin-induced thrombocytopenia.

Traditional risk factors for venous thromboembolism include protein C deficiency, protein S deficiency, factor V Leiden mutation, the prothrombin G20210A gene mutation, and others. These are relatively minor risk factors for venous thrombosis and do not pose a risk for arterial thrombosis.¹² In contrast, antiphospholipid antibody syndrome and malignancy pose a risk for both venous and arterial thrombosis. Paradoxical embolism is a mechanism by which arterial thrombosis (emboli) can develop in the setting of existing venous thrombosis.¹²

Our patient underwent testing for antiphospholipid antibodies and lupus anticoagulant, and he was encouraged to undergo age-appropriate cancer screening as an outpatient.¹²

ANTIPHOSPHOLIPID ANTIBODY SYNDROME

Antiphospholipid antibody syndrome is defined by both clinical and laboratory criteria. Clinical symptoms include vascular thrombosis (arterial, venous, or both) and pregnancy-related complications.¹³

Laboratory criteria require the presence of antiphospholipid antibodies or lupus anticoagulant. These must be confirmed with repeat testing in 12 weeks. Antiphospholipid antibodies are detected by an enzyme-linked immunosorbent assay; laboratory assessment for the presence of lupus anticoagulant is a stepwise process and relies on 4 criteria:

• There should be prolongation of a phospholipid-dependent clotting test (eg, activated partial thromboplastin time, dilute Russell viper venom time test).
• There must be evidence of an inhibitory activity with mixing study.
• The inhibitor must exhibit phospholipid dependence; that is, with more phospholipid there is shortening of clotting time.
• Specific inhibitors must be excluded, including factor VIII and anticoagulant drugs such as heparin.^14–17

From Houghton DE, Moll S. Antiphospholipid antibodies. Vasc Med 2017; 22:545–550.

Clinically, one should consider antiphospholipid antibody syndrome in patients who have arterial thrombosis, a history of pregnancy morbidity, or unexplained prolongation of activated partial thromboplastin time.¹³

Antiphospholipid antibodies may be present in up to a quarter of patients with venous thromboembolism, but it is persistent positivity of antibody assays that is associated with increased future risk of venous thromboembolism.¹⁹ Of note, the risk of venous thromboembolism in patients with confirmed antiphospholipid antibody syndrome is 10 times higher than in the general population.²⁰

ANTIPHOSPHOLIPID ANTIBODIES ARE NOT ALL THE SAME

6. Which of the following antiphospholipid antibodies have not been associated with an increased thrombotic risk?

• Anti-beta-2-glycoprotein I IgG
• Lupus anticoagulant
• Antiphosphatidylserine
• Anticardiolipin IgM
• Anticardiolipin IgG

The correct answer is antiphosphatidylserine.¹⁵

Antiphospholipid antibodies are directed against a portion of select plasma proteins that are uncovered upon phospholipid binding. While lupus anticoagulant, anti-beta-2-glycoprotein I, and anticardiolipin antibodies are associated with thrombosis, antiprothrombin antibodies (including antiprothrombin and antiphosphatidylserine antibodies) are not.^15,21

Patent foramen ovale, a communication between the right and left atrium in the interatrial septum, is associated with an increased risk of paradoxical embolization. The prevalence of patent foramen ovale is estimated to be 27% to 29% in the general population.²² Noncerebral systemic paradoxical embolism occurs less frequently than cerebral embolism, accounting for approximately 5% to 10% of paradoxical emboli.²²

To evaluate for patent foramen ovale, transthoracic echocardiography is performed with a bubble (agitated saline contrast) study to assess for interatrial shunting. Transesophageal echocardiography or transcranial Doppler bubble studies may also be performed.

Although patent foramen ovale is most commonly associated with cerebral embolism, peripheral emboli can occur. Some research suggests that this may be a more common cause of arterial thromboembolism in younger patients. There have also been reports of other sites of systemic embolization, including the renal artery.¹²

Back to our patient

Initial antiphospholipid antibody testing was positive for lupus anticoagulant. Anticardiolipin and anti-beta-2-glycoprotein I antibodies were not detected.

Transesophageal echocardiography revealed a patent foramen ovale with a highly mobile atrial septum (atrial septal aneurysm).

The patient was treated with intravenous unfractionated heparin with bridging to warfarin with a target international normalized ratio (INR) of 2 to 3. His renal artery infarction and his lower-extremity arterial thromboembolic event were conservatively managed. His respiratory status improved, and he no longer required supplemental oxygen. His creatinine peaked at 1.7 mg/dL during his admission and improved to 1.2 mg/dL before he was discharged.

At follow-up, repeat echocardiography showed that his right ventricular systolic pressure had improved (decreased) to 37 mm Hg from 54 mm Hg. Repeat confirmatory testing was positive for lupus anticoagulant 12 weeks later. He has been maintained on warfarin with an INR goal of 2 to 3 as well as low-dose aspirin with plans for long-term anticoagulation. We decided to keep the patient on anticoagulation indefinitely with warfarin; he was not a candidate for a direct oral anticoagulant, given limited data on the use of these agents in the setting of lupus anticoagulant and antiphospholipid antibody syndrome.

SUMMARY OF CASE

In summary, this patient was a 75-year-old man with COPD who presented with abdominal pain. He was noted to have a left renal infarction, extensive unprovoked lower-extremity deep vein thrombosis with pulmonary emboli, and lower limb arterial thromboembolism.

He also had an underlying hypercoagulable state—antiphospholipid antibody syndrome—that predisposed him to both arterial and venous thrombosis. He was ultimately found to have a patent foramen ovale, which further increased the risk of arterial thrombosis by facilitating paradoxical embolization of venous thrombi. It is not certain whether the renal infarction and leg artery thrombi were due to paradoxical embolism or to in situ thrombosis, but we believe that it was most likely paradoxical embolization.        

A 75-year-old man presented to the emergency department for evaluation of abdominal pain. He had stage 3 chronic obstructive pulmonary disease (COPD), with a forced expiratory volume in 1 second of 33%.

PREVIOUS HOSPITALIZATION

Aside from his COPD, he had been healthy until 1 month earlier, when he had been hospitalized because of shortness of breath and chest pressure with exertion. His troponin T level had been elevated, peaking at 0.117 ng/mL (reference range 0–0.029).

Left heart catheterization had shown no significant coronary artery disease. A myocardial bridge of the distal left anterior descending coronary artery had been seen, so that the artery appeared to be narrowed by 50% to 60% with ventricular contraction. But this was not thought to have been the cause of his presentation.

On discharge, he required oxygen 4 L/min by nasal cannula. Previously, he had not needed supplemental oxygen.

CURRENT PRESENTATION

The patient described persistent and severe periumbilical abdominal pain during the previous day. It was not associated with eating, and he denied diarrhea, constipation, hematemesis, hematochezia, bright red blood per rectum, or melena. He continued to describe persistent shortness of breath and pleuritic chest pain. His vital signs were as follows:

• Heart rate 104 beats per minute
• Respiratory rate 16 to 20 breaths per minute
• Blood pressure 101–142/62–84 mm Hg
• Oxygen saturation 78% on room air.

His laboratory findings on presentation are shown in Table 1, and his electrocardiogram is shown in Figure 1.

WHAT DOES HIS ELECTROCARDIOGRAM SHOW?

1. Which of the following is the most accurate description of this patient’s electrocardiogram?

• Sinus tachycardia, peaked P waves (P pulmonale) in lead II, and T-wave inversions in the right precordial leads
• Sinus tachycardia and left bundle branch block
• Sinus tachycardia and poor R-wave progression
• Sinus tachycardia and ST elevation in the precordial leads

Our patient’s electrocardiogram shows sinus tachycardia, P pulmonale, T-wave inversion in the right precordial leads (V₁–V₃), and biphasic T waves in lead V_4,, which suggest right ventricular strain.

The rhythm most commonly seen in patients with pulmonary embolism is sinus tachycardia, followed by nonspecific ST-segment or T-wave abnormalities. In one series of patients with acute pulmonary embolism, the classic findings of P pulmonale, right ventricular hypertrophy, right axis deviation, and right bundle branch block were rare (< 6%).¹ Thus, these classic findings are not sensitive for the diagnosis of pulmonary embolism, and their absence does not rule it out.

Further studies for our patient

Transthoracic echocardiography was performed to look for evidence of right ventricular strain secondary to the pulmonary embolism.

2. Which of the following findings on transthoracic echocardiography would not suggest acute pulmonary embolism?

• Midright ventricular wall hypokinesis with apical sparing
• Severe tricuspid regurgitation
• Left ventricular dilation
• Lack of respiratory variation of the inferior vena cava
• Septal wall motion toward the left ventricle

Left ventricular dilation does not suggest acute pulmonary embolism. Echocardiograms of patients with acute submassive pulmonary embolism typically show evidence of right ventricular strain, such as the other entities listed above (midright ventricular hypokinesis with apical sparing, severe tricuspid regurgitation, lack of respiratory variation of the inferior vena cava, and septal wall motion toward the left ventricle).

The degree of right ventricular dysfunction is related to the extent of acute pulmonary vascular occlusion and aids in risk-stratification of patients with acute pulmonary embolism. Midright ventricular wall hypokinesis with apical sparing has been termed the McConnell sign.²

In our patient, transthoracic echocardiography showed:

• Normal left ventricular ejection fraction
• Mild diastolic dysfunction
• Right ventricular dilation with moderately decreased right ventricular systolic function and apical sparing
• Right ventricular systolic pressure 54 mm Hg, consistent with moderate pulmonary hypertension
• Right atrial pressure 10 mm Hg
• No inspiratory collapse of a dilated inferior vena cava
• Mild tricuspid valve regurgitation.

CLASSIFICATION OF ACUTE PULMONARY EMBOLISM

3. Given the above information, how would you classify the patient’s pulmonary embolism?

• Massive
• Submassive
• Low-risk
• Clinically stable

The patient’s pulmonary embolism is submassive.

Historically, the classification of pulmonary embolism was determined by the angiographic thrombus burden. However, this has limited utility because clinical factors (eg, hypotension on initial presentation) have been shown to be better predictors of short-term mortality risk.³

Our patient is characterized as having a submassive pulmonary embolism based on elevated biomarkers (troponin T, N-terminal pro-B-type natriuretic peptide) and right ventricular dysfunction in the absence of hypotension.

ULTRASONOGRAPHY FOR DIAGNOSIS OF DEEP VEIN THROMBOSIS

Venous duplex ultrasonography has become the standard for diagnosis of lower extremity deep vein thrombosis. However, its quality and diagnostic accuracy depend on the skill of the person performing the examination. It is further limited by certain patient characteristics, including severe obesity, edema, and wounds and dressings at the site being examined.⁵

Our patient underwent duplex ultrasonography of the lower extremities, which demonstrated acute proximal and calf deep vein thrombosis in the right femoral, popliteal, and peroneal veins and no deep vein thrombosis in the left leg.

Multiple models exist to estimate the risk of complications in patients with acute pulmonary embolism.

The Bova score⁶ is based on the following factors:

• Systolic blood pressure 90–100 mm Hg (2 points) (patients with systolic blood pressure lower than 90 mm Hg were excluded from the study from which this score was derived)
• Cardiac troponin elevation (2 points)
• Right ventricular dysfunction on echocardiography or computed tomography (2 points)
• Heart rate 100 beats/min or greater (1 point).

A total score of 0, 1, or 2 (stage I) denotes low risk, 3 or 4 points (stage II) intermediate risk, and more than 4 points (stage III) high risk.

The PESI score (Pulmonary Embolism Severity Index)⁷ is based on:

• Age (1 point per year)
• Sex (10 points for being male)
• Heart rate 110 per minute or greater (20 points)
• Cancer (30 points)
• Heart failure (10 points)
• Chronic lung disease (10 points)
• Systolic blood pressure less than 100 mm Hg (30 points)
• Respiratory rate at least 30 per minute (20 points)
• Temperature less than 36ºC (20 points)
• Altered mental status (60 points)
• Arterial oxygen saturation less than 90% (20 points).

The total score is broken down into 5 classes: I (< 65 points), II (65–85), III (86–105), IV (106–125), and V (> 126). Classes I and II are low risk, and the higher ones are high risk.

The simplified PESI score⁸ was developed to more rapidly risk-stratify patients and has been found to be similar to the PESI score in prognostic accuracy. Patients get 1 point for each of the following:

• Age over 80
• Cancer
• Chronic cardiopulmonary disease (heart failure or chronic lung disease)
• Heart rate 110 per minute or greater
• Systolic blood pressure less than 100 mm Hg
• Arterial oxygen saturation less than 90%.

A total score of 0 is low risk; anything higher is high risk.

Back to our patient

Our patient had proximal and calf deep vein thrombosis of the right leg, bilateral submassive pulmonary emboli with associated biomarker elevation and right ventricular dysfunction, and left renal artery thrombosis with infarction. Using the PESI score, his risk of death in the next 30 days was 13.7% and his 30-day risk of a complicated course was 27%. Using the Bova score, his 30-day risk of death was 15.5% and his 30-day risk of a complicated course was 29.2%.^6,7

Notably, the patient’s right ventricular function had also been impaired on the echocardiogram performed during his admission 1 month previously. On transthoracic echocardiography during the current admission, the patient was found to have a similar degree of right ventricular dysfunction. This finding, along with the oxygen requirement that developed during the earlier admission, suggested that his pulmonary embolism may have been subacute and that the diagnosis may have been missed during the earlier hospital stay.

The patient was treated with unfractionated heparin. After the hospital’s multidisciplinary pulmonary embolism response team discussed and weighed the above factors, they recommended to not pursue thrombolytic therapy or inferior vena cava filter placement.

Of note, the patient’s pulses in the left lower extremity continued to be weak but palpable, and the left leg was cooler to touch than the right leg.

ASSESSING PERIPHERAL ARTERY DISEASE

4. How should the finding of weak pulses in this patient’s left leg be initially investigated?

• Computed tomographic angiography with runoff
• Ankle-brachial indices with pulse-volume recordings
• Arterial duplex ultrasonography
• Magnetic resonance angiography of the lower extremities

The ankle-brachial index is the initial diagnostic test for assessment of pulse abnormalities and for diagnosis of lower-extremity peripheral artery disease. It is calculated by dividing the higher of the ankle systolic pressures (posterior tibial or dorsalis pedis) by the higher of the 2 brachial pressures (left or right).⁹ Normal values are between 1.00 and 1.40.

Ankle-brachial indices in our patient

Our patient underwent measurement of his brachial, dorsalis pedis, and posterior tibial artery systolic pressures using blood pressure cuffs and continuous-wave Doppler. Ankle pulse-volume recordings were also obtained.

Given the patient’s poor renal function and concern for acute renal infarction, we thought it best to avoid iodinated or gadolinium contrast, such as with magnetic resonance or computed tomographic angiography.

Segmental leg pressures and pulse-volume recordings can be performed to help localize the level of arterial disease in the extremities, but were not done in this case because of the extensive deep vein thrombosis in the right leg.^10,11

Arterial ultrasonography in our patient

Arterial duplex ultrasonography was performed to help determine the location of arterial disease. It showed patent arteries in the right leg. In the left lower extremity there was slow, monophasic blood flow in the distal superficial femoral artery. The popliteal artery was occluded. The posterior tibial artery was occluded at the origin, with reconstitution distally. The peroneal artery was occluded throughout. The anterior tibial artery was patent throughout. The ultrasonographic findings were thought to be suspicious for arterial thromboembolism.

5. Given that the patient had both arterial thrombosis (renal artery, lower-extremity arteries) and venous thromboembolism (deep vein thrombosis and pulmonary embolism), which of the following would be included in the differential diagnosis?

• Antiphospholipid antibody syndrome
• Protein C or protein S deficiency
• Malignancy
• Paradoxical embolization
• Factor V Leiden mutation

Correct answers include antiphospholipid antibody syndrome, malignancy, and paradoxical embolization.

The differential diagnosis for concomitant venous and arterial thrombosis is broad,¹² and includes the following:

• Structural factors: patent foramen ovale, popliteal artery aneurysm
• Malignancy
• Inflammatory diseases: Behçet disease, Buerger disease, inflammatory bowel disease, antiphospholipid antibody syndrome, elevated lipoprotein(a), elevated homocysteine
• Hematologic diseases: myelodysplastic syndrome, disseminated intravascular coagulation, paroxysmal nocturnal hemoglobinuria, heparin-induced thrombocytopenia.

Traditional risk factors for venous thromboembolism include protein C deficiency, protein S deficiency, factor V Leiden mutation, the prothrombin G20210A gene mutation, and others. These are relatively minor risk factors for venous thrombosis and do not pose a risk for arterial thrombosis.¹² In contrast, antiphospholipid antibody syndrome and malignancy pose a risk for both venous and arterial thrombosis. Paradoxical embolism is a mechanism by which arterial thrombosis (emboli) can develop in the setting of existing venous thrombosis.¹²

Our patient underwent testing for antiphospholipid antibodies and lupus anticoagulant, and he was encouraged to undergo age-appropriate cancer screening as an outpatient.¹²

ANTIPHOSPHOLIPID ANTIBODY SYNDROME

Antiphospholipid antibody syndrome is defined by both clinical and laboratory criteria. Clinical symptoms include vascular thrombosis (arterial, venous, or both) and pregnancy-related complications.¹³

Laboratory criteria require the presence of antiphospholipid antibodies or lupus anticoagulant. These must be confirmed with repeat testing in 12 weeks. Antiphospholipid antibodies are detected by an enzyme-linked immunosorbent assay; laboratory assessment for the presence of lupus anticoagulant is a stepwise process and relies on 4 criteria:

• There should be prolongation of a phospholipid-dependent clotting test (eg, activated partial thromboplastin time, dilute Russell viper venom time test).
• There must be evidence of an inhibitory activity with mixing study.
• The inhibitor must exhibit phospholipid dependence; that is, with more phospholipid there is shortening of clotting time.
• Specific inhibitors must be excluded, including factor VIII and anticoagulant drugs such as heparin.^14–17

From Houghton DE, Moll S. Antiphospholipid antibodies. Vasc Med 2017; 22:545–550.

Clinically, one should consider antiphospholipid antibody syndrome in patients who have arterial thrombosis, a history of pregnancy morbidity, or unexplained prolongation of activated partial thromboplastin time.¹³

Antiphospholipid antibodies may be present in up to a quarter of patients with venous thromboembolism, but it is persistent positivity of antibody assays that is associated with increased future risk of venous thromboembolism.¹⁹ Of note, the risk of venous thromboembolism in patients with confirmed antiphospholipid antibody syndrome is 10 times higher than in the general population.²⁰

ANTIPHOSPHOLIPID ANTIBODIES ARE NOT ALL THE SAME

6. Which of the following antiphospholipid antibodies have not been associated with an increased thrombotic risk?

• Anti-beta-2-glycoprotein I IgG
• Lupus anticoagulant
• Antiphosphatidylserine
• Anticardiolipin IgM
• Anticardiolipin IgG

The correct answer is antiphosphatidylserine.¹⁵

Antiphospholipid antibodies are directed against a portion of select plasma proteins that are uncovered upon phospholipid binding. While lupus anticoagulant, anti-beta-2-glycoprotein I, and anticardiolipin antibodies are associated with thrombosis, antiprothrombin antibodies (including antiprothrombin and antiphosphatidylserine antibodies) are not.^15,21

Patent foramen ovale, a communication between the right and left atrium in the interatrial septum, is associated with an increased risk of paradoxical embolization. The prevalence of patent foramen ovale is estimated to be 27% to 29% in the general population.²² Noncerebral systemic paradoxical embolism occurs less frequently than cerebral embolism, accounting for approximately 5% to 10% of paradoxical emboli.²²

To evaluate for patent foramen ovale, transthoracic echocardiography is performed with a bubble (agitated saline contrast) study to assess for interatrial shunting. Transesophageal echocardiography or transcranial Doppler bubble studies may also be performed.

Although patent foramen ovale is most commonly associated with cerebral embolism, peripheral emboli can occur. Some research suggests that this may be a more common cause of arterial thromboembolism in younger patients. There have also been reports of other sites of systemic embolization, including the renal artery.¹²

Back to our patient

Initial antiphospholipid antibody testing was positive for lupus anticoagulant. Anticardiolipin and anti-beta-2-glycoprotein I antibodies were not detected.

Transesophageal echocardiography revealed a patent foramen ovale with a highly mobile atrial septum (atrial septal aneurysm).

The patient was treated with intravenous unfractionated heparin with bridging to warfarin with a target international normalized ratio (INR) of 2 to 3. His renal artery infarction and his lower-extremity arterial thromboembolic event were conservatively managed. His respiratory status improved, and he no longer required supplemental oxygen. His creatinine peaked at 1.7 mg/dL during his admission and improved to 1.2 mg/dL before he was discharged.

At follow-up, repeat echocardiography showed that his right ventricular systolic pressure had improved (decreased) to 37 mm Hg from 54 mm Hg. Repeat confirmatory testing was positive for lupus anticoagulant 12 weeks later. He has been maintained on warfarin with an INR goal of 2 to 3 as well as low-dose aspirin with plans for long-term anticoagulation. We decided to keep the patient on anticoagulation indefinitely with warfarin; he was not a candidate for a direct oral anticoagulant, given limited data on the use of these agents in the setting of lupus anticoagulant and antiphospholipid antibody syndrome.

SUMMARY OF CASE

In summary, this patient was a 75-year-old man with COPD who presented with abdominal pain. He was noted to have a left renal infarction, extensive unprovoked lower-extremity deep vein thrombosis with pulmonary emboli, and lower limb arterial thromboembolism.

He also had an underlying hypercoagulable state—antiphospholipid antibody syndrome—that predisposed him to both arterial and venous thrombosis. He was ultimately found to have a patent foramen ovale, which further increased the risk of arterial thrombosis by facilitating paradoxical embolization of venous thrombi. It is not certain whether the renal infarction and leg artery thrombi were due to paradoxical embolism or to in situ thrombosis, but we believe that it was most likely paradoxical embolization.        