Aortic stenosis

Overview

•William's syndrome (Williams-Beuren syndrome) - most strongly associated with supravalvular aortic stenosis; caused by elastin gene deletion on chromosome 7q11.23
•Ankylosing spondylitis - associated with aortic regurgitation (not stenosis)
⚠️
Aortic regurgitation (not stenosis) is associated with ankylosing spondylitis - a common exam distractor.

Presentation

•SAD triad of symptomatic severe AS:
•Syncope - exertional; fixed obstruction limits cardiac output increase + peripheral vasodilation → net BP fall
•Angina - hypertrophied LV O₂ demand exceeds supply; ~50% have co-existing coronary artery disease
•Dyspnoea - earliest and most common; elevated LV end-diastolic pressure → pulmonary venous congestion
•Prognosis once symptomatic (without intervention): ~2-3 years after angina, ~3 years after syncope, ~1-2 years after heart failure onset

Investigations

🥇 First-line

•ECG - LVH (tall R in V5/V6, deep S in V1/V2), LBBB, prolonged PR interval, left axis deviation

🏆 Gold standard

•Transthoracic echocardiogram (TTE) with Doppler - confirms diagnosis, quantifies severity (mean gradient, valve area, aortic jet velocity), assesses LVEF
•Severity thresholds (echo): mean gradient <40 mmHg = mild/moderate; mean gradient ≥40 mmHg = severe

Management

•Intervention is indicated when: symptomatic severe AS OR LVEF <50% OR mean gradient >40 mmHg
•Asymptomatic with LVEF >50% and mean gradient <40 mmHg → no intervention, annual review
🎯
Presence of symptoms is the primary trigger for valve replacement. Once symptomatic, mortality without intervention is approximately 50% at one year.
SAVR vs TAVI - selection
FeatureSAVRTAVI
Patient profileYoung, low/medium operative riskHigh operative risk, older
Indication thresholdSymptomatic, LVEF <50%, or mean gradient >40 mmHgSame thresholds, high surgical risk
•Medical therapy - does NOT slow progression; diuretics for pulmonary congestion; ACE inhibitors and beta-blockers used cautiously for co-existing heart failure (excessive afterload reduction can precipitate haemodynamic compromise)
•Percutaneous mitral balloon valvotomy - used for mitral stenosis, NOT aortic stenosis

Follow-up

•Severe AS (awaiting/deferred intervention) - echocardiogram every 6-12 months
•Moderate AS - echocardiogram every 1-2 years
•Mild AS - echocardiogram every 3-5 years
•Post-intervention: lifelong anticoagulation with mechanical valve only; bioprosthetic/TAVI do not require long-term anticoagulation unless other indications

Examination findings

•Ejection systolic (crescendo-decrescendo) murmur - loudest at 2nd right ICS, radiates to carotids
•Slow-rising, low-volume carotid pulse (pulsus parvus et tardus)
•Narrow pulse pressure
•Heaving, non-displaced apex beat (concentric LVH)
•Soft or absent S2 (A2) - correlates with severity of calcification
Aortic stenosis vs aortic sclerosis
FeatureAortic stenosisAortic sclerosis
MurmurEjection systolic, radiates to carotidsEjection systolic, NO carotid radiation
S2Soft or absent A2Normal/preserved
PulseSlow-rising, low-volumeNormal
Pressure gradientPresentAbsent - no obstruction