Aortic stenosis is narrowing of the aortic valve. This is the one-way valve that lets blood leave the heart’s main pumping chamber and travel to the rest of the body. As the valve narrows, the heart has to work harder to push blood through it. Many people have no symptoms in the early stages, sometimes for years. When narrowing becomes severe and starts to cause symptoms such as breathlessness, chest tightness or fainting, the definitive treatment is valve replacement, done either surgically or through a catheter-based procedure.
What the aortic valve does, and what stenosis means
The aortic valve sits between two parts of the heart. On one side is the left ventricle, the heart’s main pumping chamber. On the other is the aorta, the large artery that carries oxygen-rich blood to the rest of the body. It opens with each heartbeat and closes between beats.
“Stenosis” simply means narrowing. In aortic stenosis, the valve’s leaflets stop opening fully. The left ventricle then has to push harder to force blood through a smaller opening. Over months and years, that extra effort thickens the heart muscle, and eventually this can affect how well the heart works. This is why important aortic stenosis needs regular follow-up, even before any symptoms are obvious.
What causes aortic stenosis
In older adults, the usual cause is gradual calcification, a build-up of calcium deposits on the valve leaflets. This makes the leaflets stiffer and thicker, so they can no longer open fully.
Some people are born with a bicuspid aortic valve, which has two leaflets instead of the usual three. This valve can narrow much earlier in life, sometimes alongside enlargement of the aorta itself. Rheumatic heart disease, once a common cause, is now much less common in current UK practice.
Symptoms: what to notice, and the trap of doing less
The classic symptoms of aortic stenosis are breathlessness on exertion, chest pain or tightness with activity, dizziness or fainting (especially during exertion), and a general drop in exercise tolerance alongside unusual tiredness. These may develop so gradually that their onset is difficult to recognise.
That gradual onset creates a common diagnostic trap. People start taking the lift instead of the stairs. They pause halfway up a hill, or do the gardening in shorter bursts, often without noticing the pattern. They may then describe themselves as “fine”, simply because they have quietly stopped doing the things that would reveal a problem. This is why a careful history has to ask what someone used to manage, not just what they can do now. If you’re unsure whether your breathlessness has a cardiac explanation, a structured breathlessness assessment is often a more useful starting point than trying to interpret symptoms alone.
It’s also worth being clear that symptoms alone are an unreliable guide. Breathlessness, fatigue and chest discomfort have many causes unrelated to the aortic valve, including poor fitness, lung disease and other cardiac conditions. On the other hand, some people with genuinely severe stenosis on scanning report surprisingly few symptoms, or put them down to age. Neither the presence nor the absence of symptoms, on its own, confirms or rules out important valve disease.
Diagnosis: murmur, echocardiography, and why one scan label isn't the whole story
A systolic murmur, an extra sound heard through a stethoscope during the heartbeat, is often the first clue that prompts further assessment. A dedicated heart murmur assessment is a reasonable next step if one has been picked up.
The principal diagnostic test is transthoracic echocardiography, an ultrasound scan of the heart. This shows several things: the valve’s anatomy and degree of calcification, the velocity and pressure difference of blood as it crosses the valve, an estimate of the valve’s effective opening area, and how the left ventricle has responded to the extra workload.
A single echo report and symptom description don’t always tell the full story. Severity assessments can sometimes be discordant, meaning different measurements from the same scan point in different directions. Or a patient’s reported symptoms may not sit comfortably with how severe the valve narrowing appears. In these uncertain cases, a cardiologist may recommend repeat expert echocardiography. Alternatively, they may use more specific tests. Exercise testing can show whether symptoms or blood pressure changes emerge under controlled exertion. Cardiac CT can assess calcium in the aortic valve. In selected low-flow cases, dobutamine stress echocardiography uses medicine to increase the strength of contraction and blood flow while the heart is monitored. These are selected tests for specific uncertainty, not a routine package that everyone with aortic stenosis needs. A private echocardiogram remains the reasonable first investigation for most people.
Monitoring when treatment isn't yet needed
Mild aortic stenosis, and a good deal of moderate disease, is usually managed with monitoring rather than intervention. Severe disease without clear symptoms still warrants regular specialist follow-up. This matters because symptoms can be genuinely absent, easily missed, or masked by the activity-reduction pattern described above, and because the heart can start to show signs of strain even before symptoms appear. How often review is needed depends on the severity, the rate of change over previous scans, and individual clinical circumstances, so it’s set case by case rather than on a fixed schedule. The broader principles behind this kind of surveillance, including how cardiologists weigh up when watching and waiting stops being the right approach, are covered in more depth in heart valve disease: why timing matters.
Medicines: useful for related problems, but they don't open the valve
No medicine reverses calcification or opens a narrowed aortic valve. Medicines can still treat associated problems such as high blood pressure, rhythm disturbances, fluid retention or heart failure. Deciding which medicines are appropriate, and at what dose, is an individual clinical judgement. It takes the valve disease, blood pressure, kidney function and other conditions into account together, rather than something to adjust unprompted.
Treatment: SAVR and TAVI
Valve replacement is the definitive treatment once severe aortic stenosis is causing symptoms. It’s also considered in selected patients with severe but asymptomatic disease who have particular high-risk features on assessment. There are two principal routes. Surgical aortic valve replacement (SAVR) is an operation performed by a cardiac surgeon. Transcatheter aortic valve implantation (TAVI) works differently: it delivers a tissue valve through a catheter, usually via an artery at the top of the leg, and positions it inside the diseased valve.
Choosing between them is a decision made by a multidisciplinary heart valve team. They weigh up overall surgical risk, the anatomy of the valve and blood vessels, whether the valve is bicuspid, the need for any other heart surgery at the same time, expected long-term valve durability, and the patient’s own preferences. Age is one factor among several, not a simple cut-off that decides the outcome on its own. This overview covers the broader picture of valve disease and its treatment pathways in more general terms, if that context is useful: Heart Valve Disease.
When to seek urgent help
Call 999 for severe breathing difficulty, sudden chest pain that does not settle, or collapse with loss of consciousness. If exertional fainting, near-fainting, chest discomfort or worsening breathlessness has settled, seek prompt clinical assessment rather than waiting for the next routine scan. These symptoms have several possible causes and cannot be safely attributed to the valve at home.
Ongoing review
Outside these emergency situations, follow-up is matched to disease severity, with echocardiography repeated at intervals set by the cardiology team. A planned review is the normal way this condition is managed for most of the time it’s being watched.
Dr Mark Cassar offers private cardiology assessment for suspected or known aortic stenosis, including clinical evaluation, echocardiography and onward referral where specialist valve intervention is appropriate. Appointments can be arranged through cardiology appointments.
Frequently asked questions
Is aortic stenosis serious?
It can become serious, but severity varies widely, and many cases are mild or moderate and simply monitored. Once it becomes severe and symptomatic, it needs specialist treatment. This is why ongoing assessment matters even before symptoms appear.
What symptoms can aortic stenosis cause?
Aortic stenosis may cause no symptoms at first, and a murmur may be the first clue. When symptoms develop, they can include breathlessness or chest tightness during activity, dizziness, fainting and unusual tiredness. People sometimes reduce their activity without realising why, which can delay recognition.
Does aortic stenosis get worse over time?
Aortic stenosis is generally a progressive condition, though the rate varies between individuals. This is why regular monitoring is recommended for mild and moderate disease, with closer follow-up for severe disease that hasn’t yet caused symptoms.
Can medicines treat aortic stenosis?
No medicine opens a calcified aortic valve or reverses established narrowing. Medicines can, however, help manage related issues such as high blood pressure, abnormal heart rhythms or fluid retention, as part of an individualised treatment plan.
What's the difference between TAVI and open-heart surgery for aortic stenosis?
Surgical aortic valve replacement (SAVR) is an open-heart operation, while transcatheter aortic valve implantation (TAVI) delivers a replacement valve via a catheter without opening the chest. A specialist heart valve team decides which is more appropriate based on individual risk, anatomy and preferences, rather than a fixed rule.