In infective endocarditis, vegetations characteristically develop on the side of the valve exposed to the lower pressure chamber. According to this rule, where would vegetations be expected on the aortic and mitral valves respectively?

• A Ventricular surface of the aortic valve and atrial surface of the mitral valve ✓
• B Arterial surface of the aortic valve and ventricular surface of the mitral valve
• C Atrial surface of both valves
• D Ventricular surface of both valves

Explanation

High-velocity jets striking the low-pressure side of the valve damage the endothelium, so vegetations form on the ventricular surface of semilunar valves such as the aortic valve and on the atrial surface of atrioventricular valves such as the mitral valve, usually along the line of closure. Regurgitant jets may also produce satellite lesions on the opposing mural endocardium. Option B reverses the rule, and options C and D apply a single surface to both valve types incorrectly.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.