A 78-year-old man presents with exertional dyspnea and syncope on stair climbing. On examination, he has a harsh crescendo-decrescendo systolic ejection murmur at the right second intercostal space radiating to the carotids, pulsus parvus et tardus, and soft A2. Echocardiography shows severe aortic stenosis (AVA 0.7 cm², mean gradient 48 mmHg, peak velocity 4.5 m/s) with preserved LV ejection fraction and concentric LV hypertrophy. The surgical specimen reveals a tricuspid aortic valve. The structure marked **A** in the diagram—nodular calcific masses on the cusps—is characteristic of which pathophysiologic process?
A. Commissural fusion from rheumatic inflammation with fibrosis and calcification
B. Active inflammatory process with lipid infiltration, macrophages, and osteoblast-like cell differentiation depositing calcium hydroxyapatite
Congenital bicuspid valve anatomy with progressive calcification at the fused commissure
C.
D. Infective endocarditis with septic emboli and vegetative calcification
Explanation
Why option 1 is correct
The nodular calcific masses heaped on the aortic (outflow) surface of each cusp in a tricuspid valve with preserved commissures are pathognomonic for senile/degenerative calcific aortic stenosis. The underlying pathogenesis is an active inflammatory process resembling atherosclerosis, characterized by lipid infiltration, macrophage infiltration, and osteoblast-like cell differentiation that deposits calcium hydroxyapatite on the cusps. This process is driven by age, male sex, hypertension, dyslipidemia, smoking, and chronic kidney disease. The preserved commissures distinguish this from rheumatic and bicuspid stenosis, making the inflammatory calcification pattern the defining feature (ACC/AHA Valvular Heart Disease Guideline 2020).
Why each distractor is wrong
Option 2 (Commissural fusion from rheumatic inflammation): Rheumatic aortic stenosis presents with commissural fusion and is always accompanied by mitral valve involvement. This patient has a tricuspid valve with preserved commissures and no mention of mitral pathology, ruling out rheumatic disease.
Option 3 (Bicuspid valve with progressive calcification): Bicuspid aortic stenosis typically presents in the 5th–6th decade and shows calcification at the fused commissure. This patient is 78 years old with a tricuspid valve and nodular calcification distributed across all three cusps, not at a single commissure.
Option 4 (Infective endocarditis with vegetative calcification): Endocarditis produces vegetations and septic emboli, not the heaped nodular calcific masses on the outflow surface characteristic of degenerative calcification. There is no clinical history of fever, positive blood cultures, or embolic phenomena.
