American Board of Internal Medicine (ABIM) Certification Practice Exam

Which condition requires aortic valve replacement if the left ventricular ejection fraction is less than 50%?

1. Aortic stenosis

2. Aortic regurgitation

3. Mitral stenosis

4. Mitral regurgitation

The correct answer is: Aortic regurgitation

Aortic valve replacement is indicated in cases of aortic stenosis when the left ventricular ejection fraction (LVEF) is less than 50%. In the context of aortic stenosis, significant pressure overload on the left ventricle can lead to reduced ejection fraction. When the heart's ability to pump effectively is compromised, as indicated by an LVEF below this threshold, surgical intervention becomes necessary to prevent further deterioration, heart failure, and other associated complications. While aortic regurgitation can also lead to left ventricular dysfunction, the timing for surgical intervention differs. Aortic regurgitation usually requires surgical treatment based on symptomatology or significant left ventricular dilation, often assessed by different criteria. Mitral stenosis and mitral regurgitation are related to the mitral valve, and their management does not typically involve aortic valve replacement. Instead, they tend to require specific interventions that focus on the mitral valve itself. Understanding the specific thresholds and clinical presentations for each condition is crucial for appropriate management, particularly in cases of aortic stenosis where a reduced LVEF signals an urgent need for valve replacement to restore adequate cardiac function and prevent severe outcomes.