Aortic stenosis is a valvulopathy due to the aortic valve obstructing blood flow from the left ventricle to the aorta, presenting as syncope, angina, and dyspnea. It is diagnosed with echocardiography and treated in symptomatic patients with an aortic valve replacement.
Pathophysiology
- Valve calcification or scarring
- Obstructs flow out of left ventricle to aorta -> increased left ventricular pressure
- Early: left ventricular hypertrophy to compensate for increased pressure
- Late: left ventricular dilation when walls can no longer withstand pressure
- Causes mitral valve leaflets to pull apart -> mitral regurgitation
Contextual Factors
- Bicuspid aortic valve (most common cause in patients < 70 years old)
- Hypertension
- Smoking
- High cholesterol
- Rheumatic fever (most common cause in patients in underserved countries)
Clinical Manifestation
SAD Triad
- Syncope on exertion due to inadequate cardiac output to meet oxygen demand
- Angina due to increased cardiac tissue causing increased oxygen demand in the heart
- Dyspnea
Cardiac
- Orthopnea
Auscultation
- Normal S1
- Soft S2
- S4 in later stages
- Harsh crescendo-decrescendo systolic murmur in the second right intercostal space radiating to the carotid arteries
- Increases with increased left ventricular volume: leg raising, squatting, Valsalva release
- Parvus et tardus: diminished and delayed carotid upstroke
- Sustained PMI
- Systolic thrill in left upper sternal border
Pulmonary
- Paroxysmal nocturnal dyspnea
Complications
- Aortic regurgitation
- Mitral regurgitation
Diagnosis
- Echocardiography:
- Thickened, calcified aortic valve leaflets with limited mobility
- Diminished valve area
- Increased ventricular-aortic pressure gradient
| Severity | Peak Aortic Jet Velocity (m/s) | Mean Gradient (mmHg) | Valve Area (cm^2) |
|---|---|---|---|
| Mild | 2.5 - 2.9 | 10 - 20 | 1.5 - 2.0 |
| Moderate | 3 - 4 | 20 - 40 | 1.0 - 1.5 |
| Severe | > 4 | > 40 | < 1 |
| Very severe | > 5 | > 60 |
- Chest x-ray: calcified aortic cusps (lateral projection), mild enlargement
- ECG: left ventricular hypertrophy with or without ischemic ST and T wave changes
Treatment
- Symptomatic treatment only
- ECG stress testing for asymptomatic patients with severe aortic stenosis on echocardiography to provoke exertional symptoms or to find blood pressure falling 10+ mmHg below baseline
Surgery
- Balloon valvotomy (children or young adults with congenital aortic stenosis)
- Aortic valve replacement: surgical or transcatheter
Indications
- Severe aortic stenosis with:
- Symptomatic at rest or exertion
- Ejection fraction < 50% (HFmrEF or HFrEF)
- Low surgery risk with:
- BNP > 3 times normal
- Severe pulmonary hypertension
- Ejection fraction < 60%
- Rapid progression (>= 0.3 m/s/yr reduction in aortic valve area)
Medication
- Only for candidates that are too high risk for surgery
- Digoxin, diuretics, ACEi