# Aortic Stenosis

> Aortic stenosis for NEET-PG Medicine: calcific versus bicuspid, angina syncope dyspnoea survival, severity thresholds, low-flow states and TAVI versus SAVR.

- Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/aortic-stenosis
- Exam / course: NEET-PG · Subject: Medicine
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Aortic Stenosis", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/aortic-stenosis

## Direct answer

Exertional angina, syncope or dyspnoea in a patient with a harsh crescendo-decrescendo systolic murmur at the right upper sternal edge radiating to the carotids, a slow-rising low-volume pulse (parvus et tardus) and a soft or absent aortic component of the second heart sound means severe aortic stenosis — and symptom onset is everything, with classical untreated survivals of roughly five years for angina, three for syncope and two for heart failure. Severity is echocardiographic: valve area below 1 square centimetre (indexed below 0.6), mean gradient 40 mmHg or more, or peak velocity 4 m/s or more. Intervention — surgical replacement or transcatheter aortic valve implantation — follows symptoms, left ventricular dysfunction or asymptomatic high-risk criteria; no drug slows progression.

## What you must remember

- **Causes by clock:** degenerative calcific tricuspid disease in the elderly (the commonest in an ageing India), bicuspid valve presenting in the fifth-sixth decade, rheumatic stenosis younger with mitral involvement and commissural fusion.
- **Symptom triad with survival arithmetic:** angina about five years, syncope about three, dyspnoea or heart failure about two — the numbers that frame urgency once symptoms begin.
- **Examination package:** crescendo-decrescendo murmur right upper sternal border radiating to carotids, parvus et tardus carotid upstroke, soft or absent A2 with paradoxical splitting, fourth heart sound, systolic thrill; the murmur lengthens and grows with severity while A2 fades.
- **Severity thresholds:** peak velocity 4 m/s or more, mean gradient 40 mmHg or more, area below 1 square centimetre or indexed below 0.6 square centimetre per square metre; very severe means velocity 5 m/s or more or gradient 60 mmHg or more.
- **Low-flow low-gradient states:** depressed ejection fraction with small stroke volume — dobutamine stress echocardiography demonstrates contractile reserve and true severity; paradoxical low-flow with normal ejection fraction needs indexed stroke volume calculation.
- **Intervention logic:** symptoms with severe stenosis mandate intervention regardless of ejection fraction; asymptomatic triggers include ejection fraction below 50 percent, very severe stenosis with rapid progression, and abnormal exercise response — debated and individualised.
- **TAVI versus surgery:** transcatheter implantation favours elderly, frail or high operative-risk patients with femoral access; surgery favours the young and low-risk, bicuspid anatomy and coexistent lesions; balloon valvuloplasty is only a palliative bridge.
- **Pharmacological caution:** nitrates and other vasodilators, and aggressive diuresis can precipitate collapse in severe stenosis — a preload-dependent circulation; treat angina cautiously with beta-blockers and pursue definitive therapy.

## Numbers that change management

A 74-year-old has exertional syncope and the murmur above; echo shows peak velocity 4.4 m/s, mean gradient 45 mmHg, valve area 0.8 square centimetres and ejection fraction 50 percent. The reasoning runs: symptoms plus severe high-gradient stenosis equals mechanical relief, and the route follows the patient — age, frailty, iliofemoral anatomy and operative risk tilt toward transcatheter implantation here, with coronary assessment beforehand. Post-procedure care covers pacemaker risk (especially with pre-existing conduction disease) and antithrombotic plans.

Contrast two clinic decisions with the same valve numbers but no symptoms: a fit 60-year-old with severe stenosis and a normal exercise test is watched — intervention before symptoms buys no mortality benefit in the standard-risk patient; and a patient with low ejection fraction and a gradient of only 28 mmHg is not "moderate" by gradient alone — dobutamine stress separates true severe stenosis with reserve (benefits from replacement) from contractile failure (does not).

## The Indian reality

Three patterns cross Indian practice. Rheumatic aortic stenosis arrives young, fused alongside a mitral valve that needs attention in the same sitting, pushing decisions toward surgery rather than percutaneous routes. Bicuspid disease presents in the forties-to-sixties with calcific degeneration decades ahead of the tricuspid population — listen for it in younger adults and follow serially. And access economics shape the route: transcatheter implantation remains concentrated in metro centres at substantial out-of-pocket cost, while surgical replacement is covered under government insurance schemes — so the heart-team conversation in India includes finance, not just anatomy. Late presentation with decompensated failure is commoner than in Western clinics, making the vasodilator warning practical: the stenotic valve converts the circulation into a preload-dependent circuit, and liberal vasodilators or over-diuresis precipitate collapse.

## Frequently asked questions

### What classical survival is quoted for the aortic stenosis symptom triad?
Approximately five years for angina, three for syncope and two for heart failure without intervention.

### Which echo parameters define severe aortic stenosis?
Peak velocity 4 m/s or more, mean gradient 40 mmHg or more, or valve area below 1 square centimetre (indexed below 0.6 square centimetre per square metre).

### Why are vasodilators dangerous in severe aortic stenosis?
The fixed orifice makes cardiac output preload-dependent; dropping systemic resistance or venous return cannot be matched by flow across the valve.

### How is low-flow low-gradient aortic stenosis evaluated?
Dobutamine stress echocardiography (with depressed ejection fraction) or indexed stroke volume assessment (with normal ejection fraction) to separate true severe stenosis from low-flow states.

### How are TAVI and surgical replacement chosen?
Transcatheter implantation for elderly, frail or high surgical risk patients with suitable access; surgery for younger low-risk patients, bicuspid anatomy or coexistent lesions — a heart-team decision.