A 78-year-old man with hypertension and smoking history presents with a 6-month history of exertional chest pain and dyspnea. Transthoracic echocardiography shows aortic valve area of 0.8 cm² and mean gradient of 45 mmHg. The gross pathology specimen shows the structure marked **A** (heavy nodular cuspal calcification) on the aortic surface of the valve with preserved commissures. Which of the following best describes the underlying pathophysiology and etiology of this patient's aortic stenosis?
A. Congenital bicuspid aortic valve with premature calcification and a raphe dividing the valve into two cusps
B. Senile calcific degeneration of a tricuspid aortic valve with an active inflammation-mediated process resembling atherosclerosis, driven by age and cardiovascular risk factors
C. Rheumatic heart disease with commissural fusion and nodular calcification secondary to post-streptococcal inflammation
D. Infective endocarditis with vegetative deposits and calcific masses eroding the valve cusps
Explanation
Why option 1 is correct
The clinical presentation (age > 75 years, hypertension, smoking), the gross pathology findings (heavy nodular calcification on the aortic surface with preserved commissures), and the hemodynamic severity (AVA 0.8 cm², mean gradient 45 mmHg) are classic for senile calcific aortic stenosis (AS). Per the 2020 ACC/AHA Valvular Heart Disease Guidelines, senile calcific AS in patients > 75 years represents degeneration of a tricuspid aortic valve through an active, inflammation-mediated process that mirrors atherosclerosis, with risk factors including age, smoking, hypertension, hyperlipidemia, diabetes, and chronic kidney disease. The preserved commissures on the structure marked A specifically exclude rheumatic and bicuspid etiologies.
Why each distractor is wrong
Option 2 (Rheumatic heart disease): Rheumatic AS is characterized by fused commissures and a thickened, stenotic valve with a "fish-mouth" appearance, NOT preserved commissures. The patient's preserved commissural anatomy excludes this diagnosis.
Option 3 (Bicuspid aortic valve): Congenital bicuspid AS typically presents in patients < 60 years and calcifies a decade earlier than tricuspid valves. A bicuspid valve has a raphe (a fibrous ridge dividing two cusps), not the nodular calcification pattern seen here. This 78-year-old with preserved commissures has a tricuspid valve.
Option 4 (Infective endocarditis): Endocarditis produces vegetative deposits and acute valve destruction, not the chronic nodular calcification pattern on the aortic surface. Endocarditis would present acutely with fever and septic phenomena, not a 6-month insidious course.
High-YieldNEET PG
Senile calcific AS (tricuspid, age > 75, preserved commissures) is the most common valvular heart disease in adults; rheumatic AS (fused commissures) and bicuspid AS (raphe) are distinguished by commissural anatomy and age of onset.
2020 ACC/AHA Valvular Heart Disease Guidelines
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