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Health condition · Clinically reviewed

Aortic stenosis, grading, TAVI or SAVR, and when to act.

The commonest valve disease needing treatment in the developed world - and one where the right timing, the right test and the right procedure genuinely change how long you live.

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A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against ESC/EACTS 2021, AHA/ACC 2020, NICE and peer-reviewed trial data you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including TAVI in low-risk patients, PARTNER 3, Evolut Low Risk and ATLANTIS/POPular TAVI antithrombotic guidance.

Key facts

Aortic stenosis at a glance.

The essentials, in plain English - what it is, how severity is measured and what modern UK treatment looks like.

  • What it is

    Progressive narrowing of the aortic valve that obstructs left ventricular outflow - the commonest valve disease needing intervention in the developed world.

  • Main causes

    Calcific/degenerative disease in the over-65s (around 80%), bicuspid aortic valve presenting earlier, historic rheumatic disease, and rare congenital forms.

  • Severe AS definition

    Aortic valve area under 1.0 cm² (or <0.6 cm²/m² indexed), mean gradient at least 40 mmHg, peak jet velocity at least 4 m/s on echocardiogram.

  • Classic triad

    Angina, syncope and heart failure - all late features carrying a poor prognosis without valve replacement.

  • Prognosis untreated

    Symptomatic severe AS carries around 50% mortality at two to five years without valve replacement.

  • Modern treatment

    Surgical (SAVR) or transcatheter (TAVI) valve replacement - the choice depends on risk, anatomy, age and patient preference.

Why this guide matters

Timing is the treatment.

Aortic stenosis is progressive, silent for years, then suddenly urgent. The three points below shape everything else on this page.

  • Symptoms change the calculus

    Untreated symptomatic severe AS carries around 50% mortality at two to five years. Any symptom in severe AS is a Class I indication for valve replacement.

  • TAVI is not just for high risk

    PARTNER 3 and Evolut Low Risk mean TAVI is now a genuine option across the risk spectrum, decided by a Heart Team with anatomy, age and preference in mind.

  • Medical therapy does not fix AS

    Statins do not slow AS progression. The only treatment that changes prognosis is valve replacement - everything else is optimisation of comorbidity.

How the diagnosis is made

From murmur to a valve plan.

The steps a UK cardiologist will normally follow, in order - so you know what each test is for and why it is needed.

  1. 01

    Assessing

    History and cardiac exam

    Ejection-systolic murmur radiating to the carotids, slow-rising pulse, narrow pulse pressure and the classic triad of angina, syncope and breathlessness.

  2. 02

    Assessing

    ECG and chest X-ray

    ECG often shows left ventricular hypertrophy and strain. CXR may show a calcified valve, cardiomegaly or pulmonary congestion.

  3. 03

    Assessing

    Transthoracic echocardiogram (TTE)

    The primary diagnostic test - measures aortic valve area, mean gradient, peak jet velocity, LV function and LV mass to grade severity.

  4. 04

    Confirming

    BNP and functional testing

    Raised BNP or an abnormal exercise test in asymptomatic severe AS can tip the balance towards earlier intervention.

  5. 05

    Confirming

    Dobutamine stress echo if needed

    Used to characterise low-flow low-gradient severe AS (LVEF under 50%, mean gradient under 40 mmHg, small AVA) and identify true severe disease.

  6. 06

    Preparing

    Cardiac CT for TAVI planning

    Measures annulus size, calcium burden, coronary heights and femoral access. Cardiac MRI is added selectively for fibrosis assessment.

  7. 07

    Preparing

    Coronary angiography or CT-CA

    Before any valve intervention, coronary disease is mapped so revascularisation (PCI or CABG) can be planned alongside the valve procedure.

Typical timeline: first echo to a Heart Team decision in weeks, not months.

Symptoms

What aortic stenosis actually feels like.

The classic triad of angina, syncope and heart failure - plus the earlier, subtler features that should prompt an echocardiogram.

  • Exertional breathlessness

    The commonest presenting symptom - reduced exercise tolerance and dyspnoea on effort as the valve tightens.

  • Angina on exertion

    Chest pain or tightness on effort, often without significant coronary disease - part of the classic triad.

  • Syncope or presyncope

    Fainting or near-fainting on exertion - a serious late feature that warrants urgent cardiology review.

  • Heart failure

    Orthopnoea, paroxysmal nocturnal dyspnoea and peripheral oedema - the third arm of the triad and a poor prognostic marker.

  • Ejection-systolic murmur

    Harsh crescendo-decrescendo murmur at the right sternal edge, radiating to the carotids. Often the first clue on examination.

  • Slow-rising pulse

    A weak, slow-rising carotid pulse (pulsus parvus et tardus) with a narrow pulse pressure supports severe disease.

  • Silent severe AS

    Around a third of patients with severe AS remain symptom-free for a while - picked up on murmur or incidental echo.

  • Red flag - syncope on exertion

    Exertional collapse in a patient with a systolic murmur is a cardiology emergency until proven otherwise.

Treatment

How aortic stenosis is treated in the UK.

Watchful waiting while mild, then a Heart Team decision between TAVI and SAVR when severe - guided by ESC/EACTS 2021 and ACC/AHA 2020.

  • Watchful waiting

    Mild and asymptomatic moderate AS is monitored with serial echocardiograms - typically annual, more often as disease progresses.

  • Cardiovascular risk control

    Manage hypertension, cholesterol, diabetes and atrial fibrillation - statins do not slow AS progression but reduce overall cardiovascular risk.

  • Surgical AVR (SAVR)

    Open-heart valve replacement with a mechanical or bioprosthetic valve. Often preferred in younger, low-risk patients or when other cardiac surgery is needed.

  • TAVI / TAVR

    Transcatheter aortic valve implantation, usually via the femoral artery. Balloon-expandable Sapien (Edwards) and self-expanding Evolut (Medtronic) are the workhorse platforms.

  • Balloon aortic valvuloplasty

    A bridge only - used for haemodynamic stabilisation or as a step towards TAVI/SAVR. Not a durable stand-alone treatment.

  • Combined CABG and AVR

    When significant coronary disease is present, surgical valve replacement is often combined with coronary artery bypass grafting in one operation.

  • TAVI-in-TAVI or TAVI-in-SAVR

    Valve-in-valve procedures for failed prostheses - an increasingly common option as first-generation TAVI patients live longer.

  • Post-procedure antithrombotics

    Lifelong aspirin after TAVI (per ATLANTIS and POPular TAVI); warfarin for three months after bioprosthetic SAVR and lifelong for mechanical valves (INR 2.5-3.5).

TAVI or SAVR - how the Heart Team decides

A shared decision, not a single answer.

  • High surgical risk (STS over 8)

    TAVI is preferred where anatomy allows - the original evidence base and the most established indication.

  • Intermediate risk (STS 4-8)

    Either TAVI or SAVR is reasonable, based on PARTNER 2 and SURTAVI - anatomy, frailty and preference decide.

  • Low risk (STS under 4)

    PARTNER 3 and Evolut Low Risk show TAVI is a viable option; SAVR remains standard for younger patients and complex anatomy.

What this guide is based on

The sources behind every claim on this page.

International society guidance, landmark trials and UK regulatory guidance, current at the time of last review.

Key references

Guidelines and trials we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your cardiologist knows your echo, your comorbidities and your anatomy and can tell you which parts apply to you. If in doubt, get seen.

  • ESC/EACTS 2021 Guidelines for the management of valvular heart disease.

  • ACC/AHA 2020 Guideline for the management of patients with valvular heart disease.

  • PARTNER 3 trial - TAVI in low-risk patients (NEJM 2019).

  • Evolut Low Risk trial - self-expanding TAVI in low-risk patients (NEJM 2019).

  • PARTNER 2 and SURTAVI - TAVI in intermediate-risk patients.

  • ATLANTIS and POPular TAVI - antithrombotic strategy after TAVI.

  • NICE Interventional Procedures Guidance on TAVI (IPG586, updated).

  • British Heart Valve Society patient information and standards.

Red flags

When aortic stenosis needs urgent attention.

Most AS is monitored in outpatient cardiology. These are the situations that aren't - and where hospital-level care is needed quickly.

  • Exertional syncope

    Fainting on effort in a patient with a systolic murmur points to critical AS and needs urgent cardiology assessment.

  • Acute pulmonary oedema

    New severe breathlessness at rest, pink frothy sputum or hypoxia is a medical emergency - call 999.

  • New-onset angina

    Chest pain on exertion in known AS suggests progression or coexisting coronary disease and needs prompt review.

  • Symptomatic severe AS

    Any symptom in confirmed severe AS is a Class I indication for valve replacement - do not delay referral.

  • Rapid echocardiographic progression

    Peak jet velocity rising by more than 0.3 m/s per year, or a very severe Vmax over 5.5 m/s, warrants intervention discussion.

  • Falling LV ejection fraction

    A drop in LVEF below 50% in severe AS is a strong indication for valve replacement, even without symptoms.

  • Suspected infective endocarditis

    Fever, new murmur, embolic events or unexplained sepsis needs urgent blood cultures, echocardiogram and specialist care.

  • Bicuspid valve with aortopathy

    Bicuspid aortic valve is often paired with a dilated ascending aorta - regular aortic imaging is essential.

  • Post-TAVI complications

    New conduction disease, stroke symptoms, vascular access problems or fever after TAVI need urgent hospital review.

Living with it

A treatable condition, with a clear pathway.

Four things that make the biggest difference between echoes - a monitoring rhythm, sensible activity, good dental care and knowing when to speak up.

A quiet reminder

Tell your team about new symptoms early.

In severe AS, symptoms are the trigger for treatment. Waiting for the next scheduled review can cost time you don't want to lose.

  1. 01 Monitoring

    Keep your echoes on schedule

    Mild AS is usually reviewed every three to five years, moderate annually and severe every six months - do not skip appointments.

  2. 02 Activity

    Move sensibly, not competitively

    Light-to-moderate activity is encouraged in mild-to-moderate AS. Avoid heavy isometric exercise and competitive sport once AS is severe.

  3. 03 Dental

    Look after your teeth

    Good oral hygiene lowers the risk of infective endocarditis. Antibiotic prophylaxis is reserved for specific high-risk situations per NICE.

  4. 04 Escalate

    Tell someone about new symptoms

    Any new breathlessness, chest pain, dizziness or blackouts in known AS is a reason to be seen quickly - not to wait for the next scheduled review.

Frequently asked

Everything we get asked about aortic stenosis.

Quick answers on severity, the TAVI-versus-SAVR decision and what happens after valve replacement.

  • What is aortic stenosis?

    Aortic stenosis is a progressive narrowing of the aortic valve that obstructs blood flow from the left ventricle into the aorta. It is the commonest valvular heart disease requiring intervention in the developed world and most often reflects age-related calcification of the valve leaflets.

  • How is severe aortic stenosis defined?

    On echocardiography, severe AS is defined by an aortic valve area under 1.0 cm² (or under 0.6 cm²/m² when indexed to body surface area), a mean transvalvular gradient of at least 40 mmHg and a peak jet velocity of at least 4 m/s. A specific low-flow low-gradient severe AS phenotype (small AVA, mean gradient under 40, LVEF under 50%) is confirmed with dobutamine stress echo.

  • When does aortic stenosis need to be treated?

    Per ESC/EACTS 2021 and ACC/AHA 2020 guidance, valve replacement is indicated in symptomatic severe AS, and in asymptomatic severe AS with LVEF under 50%, an abnormal exercise test, a very small valve area, very high jet velocity (over 5.5 m/s), significantly raised BNP or rapid progression.

  • What is the difference between TAVI and SAVR?

    SAVR is surgical open-heart valve replacement using a mechanical or bioprosthetic valve. TAVI (transcatheter aortic valve implantation) delivers a bioprosthetic valve through a catheter, usually via the femoral artery. High surgical-risk patients typically have TAVI. Intermediate-risk patients can have either based on PARTNER 2 and SURTAVI. In low-risk patients, PARTNER 3 and Evolut Low Risk show TAVI is a viable option alongside SAVR, and the choice is now individualised by age, anatomy, comorbidity and preference.

  • Which valves are used for TAVI in the UK?

    The workhorse platforms are the balloon-expandable Sapien family (Edwards) and the self-expanding Evolut family (Medtronic). Portico (Abbott) and Acurate neo (Boston Scientific) are also used in selected centres. Femoral access is preferred where anatomy allows, with alternative access (subclavian, transcaval, transapical) reserved for unsuitable femoral arteries.

  • What blood thinners are needed after valve replacement?

    After TAVI, lifelong aspirin monotherapy is now standard per the ATLANTIS and POPular TAVI trials, with dual antiplatelet therapy only if a coronary stent has been placed. After bioprosthetic SAVR, warfarin is typically given for three months and then switched to aspirin. Mechanical valves require lifelong warfarin, target INR usually 2.5-3.5 depending on valve position and patient risk. Direct oral anticoagulants are not used for mechanical valves.

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