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Internal Medicine
Cardiology
Cardiothoracic Surgery

Aortic Stenosis

High EvidenceUpdated: 2025-12-22

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Red Flags

  • Syncope, especially exertional
  • Angina with normal coronaries
  • Acute pulmonary oedema
  • Cardiogenic shock in critical AS
  • Rapid symptom progression
Overview

Aortic Stenosis

1. Topic Overview

Summary

Aortic stenosis (AS) is the most common primary valve disease requiring intervention in developed countries. It is characterised by obstruction to left ventricular outflow due to calcific degeneration of the aortic valve leaflets. The prevalence increases with age, affecting 2-5% of those over 75 years. The classic symptom triad of angina, syncope, and dyspnoea (heart failure) marks disease progression and heralds poor prognosis without intervention. Management has been revolutionised by transcatheter aortic valve implantation (TAVI/TAVR), which now offers treatment for patients previously considered too high-risk for surgery.

Key Facts

  • Definition: Reduction in aortic valve area causing LV outflow obstruction
  • Prevalence: 2-5% of adults over 75 years
  • Main Cause: Calcific degeneration (degenerative AS)
  • Severe AS Criteria: AVA under 1.0 cm², mean gradient over 40 mmHg, peak velocity over 4 m/s
  • Prognosis Without Treatment: 50% mortality within 2 years after symptom onset
  • Treatment Options: SAVR (surgical) or TAVI/TAVR (transcatheter)

Clinical Pearls

High-Yield Points:

  • Symptom onset is the key prognostic marker
  • Classic triad: Syncope, Angina, Dyspnoea (SAD)
  • Survival after symptom onset: Angina 5 years, Syncope 3 years, HF 2 years
  • Low-gradient AS needs careful evaluation (may still be severe)
  • TAVI now approved for all surgical risk categories
  • Do not delay intervention once symptoms develop
2. Epidemiology

Prevalence

Age GroupPrevalence
65-74 years1.5%
75-84 years3.5%
Over 85 years4-5%

Causes

CauseAge GroupFeatures
Calcific/DegenerativeOver 65Most common; shares risk factors with atherosclerosis
Bicuspid Aortic Valve40-65Present in 1-2% of population; premature calcification
RheumaticAnyNow rare in developed countries; often mixed stenosis/regurgitation
3. Pathophysiology

Mechanism

  1. Valve Degeneration: Lipid deposition, inflammation, calcification
  2. Reduced Valve Area: Progressive narrowing (normal AVA: 3-4 cm²)
  3. Pressure Overload: LV must generate higher pressures
  4. Concentric Hypertrophy: Wall thickening to normalise wall stress
  5. Diastolic Dysfunction: Stiff, non-compliant LV
  6. Supply-Demand Mismatch: Subendocardial ischaemia (angina)
  7. Eventually: LV failure if obstruction not relieved

Natural History

  • Asymptomatic Period: Years to decades
  • Rate of Progression: AVA decreases 0.1-0.2 cm²/year on average
  • Symptom Onset: Marks clinical deterioration
  • Prognosis After Symptoms: Mortality 25% at 1 year, 50% at 2 years
4. Clinical Presentation

Classic Symptom Triad (SAD)

SymptomMechanismPrognosis
SyncopeExertional; fixed cardiac output, vasodilation3-year survival
AnginaSubendocardial ischaemia despite normal coronaries5-year survival
DyspnoeaLV failure, elevated filling pressures2-year survival

Other Symptoms

Signs

Auscultation:

Pulse:

Other:

Reduced exercise tolerance
Common presentation.
Fatigue
Common presentation.
Palpitations (often AF)
Common presentation.
5. Investigations

Echocardiography (Diagnostic Standard)

Severity Classification:

ParameterMildModerateSevere
Peak velocity (m/s)2.6-2.93.0-3.9≥4.0
Mean gradient (mmHg)Under 2020-39≥40
AVA (cm²)Over 1.51.0-1.5Under 1.0
Indexed AVA (cm²/m²)Over 0.850.60-0.85Under 0.6

Low-Gradient AS:

  • Low-flow, low-gradient: EF reduced; may still be severe
  • Paradoxical low-flow: Normal EF but small LV; restrictive physiology

Other Investigations

InvestigationPurpose
ECGLVH, LBBB, AF
Chest X-rayCardiomegaly, calcified valve, pulmonary congestion
CT Aortic Valve Calcium ScoreConfirms severity if echo discordant
Coronary AngiographyPre-operative assessment
Cardiac MRILVEF, fibrosis assessment
6. Management

Asymptomatic Severe AS

  • Watchful waiting if:

    • Normal LV function
    • Normal exercise tolerance
    • No very severe features

  • Consider early intervention if:

    • Peak velocity over 5 m/s
    • Severe valve calcification with rapid progression
    • BNP elevation without other cause
    • LVEF under 55%
    • Symptoms on exercise testing

Symptomatic Severe AS

Intervention indicated (Class I) for all symptomatic severe AS:

SAVR (Surgical Aortic Valve Replacement):

  • Gold standard for low surgical risk
  • Mechanical or bioprosthetic valve
  • Concomitant CABG if needed

TAVI (Transcatheter Aortic Valve Implantation):

  • Initially for high surgical risk only
  • Now approved for all risk categories
  • Preferred in elderly (over 75) and higher surgical risk
  • Transfemoral approach preferred

Choice of Intervention:

FactorFavours SAVRFavours TAVI
AgeYounger (under 65)Older (over 75)
Surgical RiskLowIntermediate to high
AnatomyBicuspid, small annulusFavourable for TAVI
Concomitant diseaseNeed CABG, other valve surgeryIsolated AS
FrailtyNot frailFrail

Medical Therapy

  • No medical treatment slows progression
  • Symptom palliation if intervention not possible
  • Avoid vasodilators (may cause hypotension)
  • Treat comorbidities (BP, lipids, diabetes)
7. Prognosis

Without Intervention

Symptom OnsetAverage Survival
Angina5 years
Syncope3 years
Heart Failure2 years

After Intervention

  • SAVR: 10-year survival 60-70%
  • TAVI: 5-year survival 50-60% (older, higher-risk population)
  • Both offer excellent symptom relief
8. Patient/Layperson Explanation

What is Aortic Stenosis?

Aortic stenosis is narrowing of the aortic valve, which is the main valve between your heart and your body. When it narrows, your heart has to work much harder to pump blood.

What causes it?

In most people over 65, it's caused by calcium building up on the valve over many years (similar to what happens in arteries). Some people are born with a valve that only has two leaflets instead of three, which wears out faster.

What are the symptoms?

You may have no symptoms for many years. Warning signs include:

  • Feeling breathless with activity
  • Chest pain or tightness
  • Fainting or feeling faint, especially with exercise

How is it treated?

Once you have symptoms, the valve usually needs to be replaced. This can be done:

  • Open heart surgery: The traditional approach, still best for younger patients
  • TAVI/TAVR: A newer technique using a catheter through your leg, better for older or higher-risk patients

Both options can dramatically improve your symptoms and quality of life.

9. References

  1. Vahanian A, et al. 2021 ESC/EACTS Guidelines for the management of valvular heart disease. Eur Heart J. 2022;43(7):561-632. PMID: 34453165

  2. Otto CM, et al. 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease. Circulation. 2021;143(5):e72-e227. PMID: 33332150

Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. It does not replace professional medical judgement.

Last updated: 2025-12-22

At a Glance

EvidenceHigh
Last Updated2025-12-22

Red Flags

  • Syncope, especially exertional
  • Angina with normal coronaries
  • Acute pulmonary oedema
  • Cardiogenic shock in critical AS
  • Rapid symptom progression

Clinical Pearls

  • **High-Yield Points:**
  • - Symptom onset is the key prognostic marker
  • - Classic triad: Syncope, Angina, Dyspnoea (SAD)
  • - Survival after symptom onset: Angina 5 years, Syncope 3 years, HF 2 years
  • - Low-gradient AS needs careful evaluation (may still be severe)

Guidelines

  • NICE Guidelines
  • BTS Guidelines
  • RCUK Guidelines