American Board of Internal Medicine (ABIM) Certification Practice Exam

When is left ventricular end-systolic dimension a criterion for aortic valve replacement?

1. Less than 30 mm

2. Greater than 50 mm

3. Between 40 mm and 60 mm

4. Exactly 50 mm

The correct answer is: Greater than 50 mm

Left ventricular end-systolic dimension (LVESD) is an important parameter in assessing heart function, particularly in the context of aortic valve replacement. The guideline thresholds for LVESD help determine when intervention, such as surgery for aortic valve replacement, may be necessary due to the impact of aortic stenosis or regurgitation on ventricular function. An LVESD greater than 50 mm is recognized as a criterion for aortic valve replacement because it indicates significant left ventricular dilation and dysfunction. This degree of dilation is often associated with advanced heart failure and bad prognosis. In patients with aortic stenosis, as the left ventricle compensates for the increased pressure load, it can enlarge to accommodate the heart's need to pump effectively. However, once this dimension exceeds certain thresholds, it is indicative of severe impairment in the heart's ability to contract efficiently, and surgical intervention is typically warranted to alleviate this pressure. Options specifying less than 30 mm, between 40 mm and 60 mm, or exactly 50 mm do not meet the guideline thresholds established for intervention. Specifically, dimensions below this benchmark often reflect a condition that may be compensated and do not yet warrant surgical consideration, while values within the range of 40 mm to