American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the diagnostic criterion for severe aortic stenosis based on Vmax?

1. Vmax ≥3.0 m/s

2. Vmax ≥4.0 m/s

3. Vmax ≥5.0 m/s

4. Vmax ≤2.0 m/s

The correct answer is: Vmax ≥4.0 m/s

Severe aortic stenosis is identified using echocardiographic criteria that measure the peak velocity (Vmax) across the aortic valve. A Vmax of 4.0 m/s or greater indicates significant stenosis, which is clinically significant and aligns with a narrowed aortic valve that leads to symptomatic heart failure or other complications. Specifically, a Vmax of 4.0 m/s suggests an increased gradient across the valve, reflecting considerable obstruction to outflow from the left ventricle. This velocity threshold corresponds to notable pressure differences that are sustained during normal exertion, contributing to the clinical picture of severe aortic stenosis. Higher values, such as a Vmax of 5.0 m/s, represent even more severe cases but are not the primary diagnostic criterion. A Vmax less than 3.0 m/s falls into the range of mild to moderate aortic stenosis and does not indicate severe disease. Additionally, a Vmax of less than or equal to 2.0 m/s is typically consistent with a normal aortic valve, thereby excluding severe stenosis altogether. Therefore, a Vmax of 4.0 m/s is the established diagnostic cutoff for severe aortic stenosis.