TAVI for Aortic Stenosis

Transcatheter aortic valve implantation (TAVI) treats severe aortic stenosis by replacing the narrowed valve through a catheter, usually passed up from the groin, without opening the chest. Aortic stenosis becomes steadily more common after 70 and is fatal within a few years of symptoms if left alone. For elderly and high-risk patients, TAVI is now the default treatment.

Dr. Subhash Chandra, Chairman - Interventional Cardiology - Cardiology & Structural Heart Disease, BLK-Max Super Speciality Hospital, New Delhi, India, performs a great deal of TAVI. His framing of the field is simple: patients increasingly want to avoid the knife and have their disease fixed with needles, wires, tubes and catheters. In cardiology, TAVI is where that shift has gone furthest. This guide sets out what aortic stenosis is, when it must be treated, how TAVI works and how it has evolved, and where the technique is heading. The procedure itself, from CT planning to access routes, is covered in how TAVI is planned and performed, and the choice between TAVI and open surgery, with cost and referral, in TAVI vs SAVR: how doctors decide.

What is aortic stenosis?

Aortic stenosis is a narrowing of the aortic valve, the valve through which the left ventricle pumps blood into the aorta and on to the rest of the body. In older adults the cause is usually progressive calcification: the valve leaflets stiffen and thicken with calcium until they no longer open fully, and the heart has to generate far higher pressure to push blood through the reduced opening.

The disease is strongly age-related. Its prevalence climbs steeply after 70, and among octogenarians Dr. Chandra put it at close to 10%. Population studies estimate that severe aortic stenosis affects roughly 3 to 4% of people aged 75 and over. Because the same ageing population carries more lung, kidney and vascular disease, the risk of replacing the valve through open heart surgery rises sharply with every decade.

Symptoms of aortic stenosis

The classical symptoms of aortic stenosis are:

• Chest pain (angina), because the thickened heart muscle needs more oxygen than the coronary arteries can supply
• Blackouts (syncope), especially on exertion, when the narrowed valve cannot let cardiac output rise
• Breathlessness and other heart failure symptoms, as pressure backs up into the lungs
• Fatigue

The difficulty is that the disease frequently goes unnoticed. Unless a patient develops symptoms or happens to undergo an echocardiogram, the narrowing can progress silently for years.

Life expectancy with untreated severe aortic stenosis

Once a patient with severe aortic stenosis develops angina, syncope or heart failure, survival without valve replacement is short. Classic natural-history data put average survival after symptom onset at about five years with angina, three years with syncope and two years with heart failure. Dr. Chandra described the chance of dying within the next two to four years as very high, and said that almost every such patient will have died by five years if nothing is done.

His second point is equally direct: medicine is not a treatment for aortic stenosis. Drugs can ease breathlessness or control blood pressure, but no medicine opens a calcified valve. The valve has to be replaced, and the clinician's task is to act in time.

When to treat aortic stenosis: the echocardiogram threshold

Echocardiography, an ultrasound scan of the heart, is the test that decides when to intervene. Dr. Chandra's threshold is a mean gradient across the aortic valve above 40 mmHg: at that point, in his practice, the valve should be treated even if the patient has no symptoms, because the risk of death over the following five years is otherwise very high.

The mean gradient is the average pressure difference across the valve while it is open, measured with Doppler ultrasound; the tighter the valve, the higher the gradient. Current European (ESC/EACTS) and American (ACC/AHA) guidelines define severe aortic stenosis by a mean gradient of 40 mmHg or more, a peak velocity of 4 m/s or more, or a valve area below 1.0 cm². For symptom-free patients, intervention is clearly indicated when there are additional high-risk features, such as a reduced ejection fraction, symptoms unmasked on an exercise test, or very severe narrowing. Following recent randomised trials, the 2025 European guideline also supports earlier intervention in selected symptom-free patients with severe aortic stenosis at low procedural risk.

Screening: how aortic stenosis is found early

Because the disease is silent for so long, screening matters. Asked what a basic annual cardiac screen for high-risk groups should include, Dr. Chandra listed:

• a thorough echocardiogram, especially in the elderly
• an ECG (electrocardiogram, a recording of the heart's electrical activity)
• blood tests: lipid profile, CRP (C-reactive protein, a marker of inflammation) and HbA1c, which reveals underlying diabetes
• a stress test where coronary artery disease needs to be uncovered

These, he said, are the classical tests conducted in most people past 40 or 45. Once the information is in hand, the work turns to prevention, and to intervening in time where an intervention is needed.

Aortic stenosis treatment: surgery, balloon valvuloplasty or TAVI

Severe aortic stenosis is treated by replacing the valve, either through open surgery or through a catheter with TAVI. Balloon valvuloplasty offers only temporary relief.

Surgical aortic valve replacement (SAVR)

The conventional treatment is surgical aortic valve replacement (SAVR): the chest is opened, the patient is placed on a heart-lung machine, the diseased valve is excised and a new valve is sutured around the annulus, the ring of tissue at the base of the aorta in which the valve sits. SAVR has been refined over more than 50 years and remains, in Dr. Chandra's view, the benchmark for safety when a patient can safely undergo it. The cost of aortic valve replacement in India is set out separately.

Balloon aortic valvuloplasty: a bridge, not a fix

In balloon aortic valvuloplasty, a balloon is inflated inside the calcified valve to crack it open. It relieves symptoms for the time being, but the recurrence rate is very high: in Dr. Chandra's description, a valve left without a definitive replacement soon narrows again. Published series report restenosis in most patients within six to twelve months. In his view it is at best reserved for patients who are too high-risk to proceed straight to TAVI: it buys time, and a month or two later the patient is brought back for TAVI, the lasting option.

What is TAVI and how does it treat aortic stenosis?

TAVI, also called transcatheter aortic valve replacement (TAVR), works much like a coronary angioplasty. A tube carries a folded replacement valve up to the heart. When it is deployed, the diseased valve is pushed aside and pressed against the wall of the aorta, and the new valve takes its place and functions like a normal valve.

The replacement is a tissue valve, the same kind of biological valve a surgeon would give an elderly patient, and Dr. Chandra expects it to last at least 10 to 15 years. When it eventually wears out, another TAVI can be placed inside it.

Two families of TAVI valve exist, balloon-expandable and self-expanding, and the femoral artery in the groin is the commonest and safest route to the valve. Alternative routes run through the subclavian or carotid artery, directly into the aorta, or from the femoral vein.

How TAVI evolved

The first TAVI was performed in 2002 by Professor Alain Cribier in France, using a balloon-expandable valve. For more than a decade the technique was offered only to patients considered too high-risk for surgery: the classic TAVI patient is old and frail, with comorbidities such as chronic kidney disease, poor lungs, peripheral vascular disease, atrial fibrillation, cancer or liver disease that make open heart surgery impossible. Dr. Chandra's observation is that many of these patients go on to enjoy life after the procedure despite carrying so many illnesses.

The indication has since widened. Randomised trials in intermediate-risk patients (PARTNER 2 and SURTAVI) and then in low-risk patients (PARTNER 3 and Evolut Low Risk, both reported in 2019) showed TAVI to be non-inferior to surgical replacement. Two practical advances drove its popularity, in Dr. Chandra's account: steadily smaller delivery systems, and the ease of performing the procedure on a conscious patient. Most transfemoral TAVI is now done under local anaesthesia, with or without light sedation.

The scale is now considerable. By Dr. Chandra's estimate, close to 10,000 patients have been treated with TAVI in India alone, and the global total runs far higher.

Beyond the aortic valve: valve-in-valve and TMVR

The same transcatheter principle now extends to failed surgical valves. A patient whose earlier surgical aortic valve has degenerated can receive a TAVI valve inside it (a valve-in-valve procedure) rather than a second open operation. In the mitral position, where a previous surgical mitral valve replacement has failed, a similar balloon-expandable valve can be placed inside the old one from the femoral vein, a procedure known as transcatheter mitral valve replacement (TMVR).

The future of TAVI

Dr. Chandra described the future of TAVI as very bright, and identified the problems the field is now working on:

• Durability. Longevity is an issue. The aim is to extend valve life beyond 15 years so that a patient does not need a second TAVI in their lifetime. Newer leaflet materials, such as the RESILIA tissue used on Edwards valves, are designed to resist the calcification that wears out biological valves.
• Bicuspid valves. Patients born with a two-leaflet (bicuspid) aortic valve have anatomy that was once considered unsuitable, and are increasingly being treated with TAVI.
• Stroke prevention. Cerebral embolic protection devices, which capture debris released during the procedure, are available to reduce the risk of stroke. Large randomised trials (PROTECTED TAVR, 2022; BHF PROTECT-TAVI, 2025) did not show a significant reduction in stroke with their routine use.
• Coronary access. Techniques such as BASILICA, which deliberately splits a leaflet that would otherwise block a coronary artery, protect coronary flow in high-risk anatomy.
• Pure aortic regurgitation. In a leaking (rather than narrowed) valve with a very large annulus, conventional TAVI valves have little calcium to anchor to; dedicated valves designed for this anatomy are being developed and could open TAVI to these patients.

Heart-healthy lifestyle: diet and exercise

Dr. Chandra's lifestyle advice for heart health rests on regular exercise, a diet low in saturated fat and a stress-free daily routine. Running, in his view, is a very good and complete form of exercise. In diet, he advises avoiding a lot of red meat, which is high in saturated fat and cholesterol; relying more on vegetarian foods such as grains, millets and dry fruits; and limiting saturated fat, including that in milk and milk products. A stress-free life and a daily routine that includes exercise matter as much: yoga, which he practises himself, running, weight training or any other form. Staying happy, he concluded, is most important.

Further reading from this masterclass

• The questions doctors asked Dr. Chandra, on complications, prognosis and screening, are answered in the Live Discussion from this masterclass.
• More on heart disease from the cardiology specialty hub.