Definition:
Narrowing of the aortic valve opening, impeding blood flow from the left ventricle to the aorta.
- Normal valve area: ~3 cm²
- Clinically significant stenosis: <1.5 cm²
Etiology
- Age-related calcific degeneration – most common cause in older adults (65–70 years)
- Congenital bicuspid aortic valve – 2 valve leaflets instead of 3, prone to early degeneration
- Post-inflammatory damage – typically from acute rheumatic fever
Pathogenesis
- Valve narrowing → LV needs to generate higher pressure to eject blood → concentric hypertrophy (sarcomeres added in parallel)
- Over time, LV decompensates: wall thins, dilation occurs, and systolic function declines → ↓ cardiac output → symptoms of HF
- Blood ejection through stenotic valve causes ejection click
- ↓ coronary perfusion during diastole → angina
- ↓ cerebral perfusion during exertion → syncope
- Advanced stages:
- ↑ LVEDP → transmitted backward → ↑ LA pressure → pulmonary congestion
- Eventually → pulmonary HTN → RV hypertrophy & failure
Stages:
- I: LV hypertrophy, ↓ peripheral perfusion
- II: LV dilatation, relative mitral regurgitation, pulmonary congestion
- III: Pulmonary hypertension → RV dilatation, relative tricuspid regurgitation