American Board of Internal Medicine (ABIM) Certification Practice Exam

In mitral stenosis, when is valve replacement indicated?

1. Onset of left ventricular hypertrophy

2. Very severe mitral stenosis even without symptoms

3. Presence of a heart murmur

4. Improvement of exercise tolerance

The correct answer is: Very severe mitral stenosis even without symptoms

In mitral stenosis, valve replacement is indicated when there is very severe mitral stenosis, even in the absence of symptoms. This is based on the understanding that the degree of stenosis correlates with the potential for complications, such as heart failure or pulmonary hypertension, even if the patient does not currently exhibit symptoms. Severe stenosis can lead to significant hemodynamic changes and eventual worsening of the patient’s condition, making early intervention critical to prevent deterioration. Symptoms may only appear once the condition has progressed considerably, so relying solely on the presence of symptoms can result in a delay in treatment until the patient is in a more compromised state. In contrast, the other scenarios do not warrant immediate valve replacement. The onset of left ventricular hypertrophy is an indicator of underlying pressure overload but does not by itself dictate the need for surgical intervention. Similarly, the presence of a heart murmur is not sufficient for surgical indication as many murmurs do not reflect severe pathology. Improvement of exercise tolerance would suggest that the condition is stable or improving, which would not necessitate valve replacement. Thus, the presence of very severe mitral stenosis is a key factor in deciding on the need for valve replacement, irrespective of symptoms.