TAVI for Severe Aortic Stenosis

Severe aortic stenosis means that the aortic valve has become significantly narrowed, making it harder for blood to leave the heart and reach the rest of the body. When the narrowing becomes severe, the heart has to work harder to pump blood through the valve, and symptoms can eventually develop.

For patients who need their aortic valve replaced, transcatheter aortic valve implantation (TAVI)—also called transcatheter aortic valve replacement (TAVR)—can provide a less invasive alternative to open surgical valve replacement.

But does every person with severe aortic stenosis need TAVI? When is it recommended, and how is the decision made? The answer depends on several factors, including symptoms, valve severity, age, life expectancy, overall health, valve anatomy and access for the procedure. For a broader overview, see our guide to TAVI / TAVR procedure.

What Is Severe Aortic Stenosis?

The aortic valve is located between the left ventricle and the aorta. It opens when the heart pumps, allowing blood to flow out of the heart, and closes afterward to prevent blood from flowing backward.

With aortic stenosis, the valve becomes narrowed, most commonly because the valve leaflets become thickened and calcified. The narrowing restricts blood flow from the left ventricle into the aorta. 

As the stenosis becomes more severe, the heart must generate greater pressure to push blood through the narrowed opening. Severe aortic stenosis can eventually lead to symptoms, reduced heart function and heart failure if it is not appropriately managed.

What Symptoms Can Severe Aortic Stenosis Cause?

Some people with severe aortic stenosis have no obvious symptoms initially. Others develop symptoms as the heart struggles to maintain adequate blood flow through the narrowed valve. Common symptoms include:

• Shortness of breath, particularly during physical activity
• Chest pain or pressure
• Dizziness or fainting, especially with exertion
• Reduced exercise tolerance
• Fatigue or unusual tiredness
• Swelling in the legs or ankles in some patients

These symptoms can also occur with other heart and lung conditions, so they do not by themselves establish that aortic stenosis is severe. However, once symptoms are confirmed to be caused by severe aortic stenosis, valve replacement becomes an important treatment consideration.

When Does Severe Aortic Stenosis Need Valve Replacement?

Not every person with severe aortic stenosis immediately needs a valve procedure. The timing of intervention depends on the severity of the valve narrowing, symptoms, heart function and other clinical findings.

Symptomatic severe aortic stenosis is one of the clearest situations in which aortic valve replacement is recommended because the symptoms indicate that the narrowed valve is affecting the heart's ability to function effectively. Valve replacement may also be considered in selected people who do not have symptoms but have evidence that the disease is placing the heart at significant risk.

For example, intervention may be considered when severe aortic stenosis is associated with reduced left ventricular ejection fraction or other high-risk features identified through testing. The decision should therefore be made by a specialist Heart Team rather than based on symptoms alone.

Where Does TAVI Fit Into the Treatment?

TAVI is a way of replacing the diseased aortic valve without surgically removing the old valve through open-heart surgery. During TAVI, a replacement biological valve is mounted within a catheter. The catheter is usually introduced through an artery in the groin and guided toward the heart.

Once the replacement valve reaches the diseased aortic valve, it is expanded into position. The new valve pushes the old, narrowed valve leaflets aside and begins controlling blood flow. The procedure is therefore different from surgical aortic valve replacement (SAVR), in which the chest is opened and the diseased valve is surgically removed and replaced.

What Factors Are Considered Before TAVI?

Before recommending TAVI, the medical team needs to determine whether the procedure is technically suitable and whether it provides the best overall strategy for the patient's lifetime care. The assessment may include:

• Severity of aortic stenosis
• Symptoms and functional status
• Age and expected life expectancy
• Overall health and other medical conditions
• Surgical risk and frailty
• Aortic valve anatomy
• Size and shape of the aortic annulus
• Coronary artery anatomy
• Condition and size of the arteries used for catheter access
• Whether the valve is tricuspid or bicuspid
• Potential need for future valve procedures

Why Is TAVI Considered Less Invasive Than Surgical Valve Replacement?

The main difference is how the replacement valve reaches the heart. Traditional surgical valve replacement generally requires an operation involving the chest and direct access to the heart. TAVI uses a catheter-based approach, most commonly through an artery in the groin, and does not require opening the chest.

This can mean a shorter and less physically demanding recovery for appropriately selected patients. However, TAVI is still a major heart procedure. Less invasive does not mean risk-free, and careful assessment is necessary before deciding that it is the right treatment.

What Happens During TAVI?

Although the exact technique varies between patients, a typical transfemoral TAVI involves several stages.

1. Pre-procedure imaging: CT and other tests are used to plan the valve size and safest access route.
2. Catheter access: The replacement valve is introduced through a blood vessel, most commonly an artery in the groin.
3. Guiding the valve: The catheter is advanced through the blood vessels toward the heart and positioned within the diseased aortic valve.
4. Valve deployment: The replacement valve is expanded and secured inside the native valve.
5. Position and function check: Imaging and other measurements are used to confirm that the new valve is functioning properly.
6. Catheter removal: The access site is closed and monitored during recovery.

What Benefits Can TAVI Provide?

The main goal of TAVI is to restore more normal blood flow through the aortic valve by replacing the severely narrowed valve. For appropriate patients, successful valve replacement can improve:

• Shortness of breath
• Exercise capacity
• Fatigue
• Quality of life
• Functional independence

In patients with symptomatic severe aortic stenosis, replacing the valve can also improve survival compared with leaving severe symptomatic disease untreated. The extent of improvement varies depending on the patient's overall health, the condition of the heart muscle and whether other heart or lung problems are also contributing to symptoms.

Is TAVI Better Than Surgical Valve Replacement?

There is no universal answer. TAVI and surgical aortic valve replacement can both be effective treatments for severe aortic stenosis, but they are not interchangeable for every patient.

TAVI may offer important advantages in appropriately selected patients, particularly because it avoids open-heart surgery and can provide a less invasive recovery. Surgical replacement may be preferred in younger patients, in some patients with bicuspid aortic valves, when other cardiac surgery is required at the same time, or when the anatomy is not suitable for TAVI.

The current approach is therefore not simply to choose the less invasive procedure. Instead, the Heart Team considers the patient's age, anatomy, surgical risk, life expectancy, associated heart conditions and future treatment needs.

What Are the Possible Risks of TAVI?

TAVI is an established treatment, but it has potential complications. Possible risks include:

• Bleeding or complications at the catheter access site
• Stroke
• Damage to blood vessels
• Abnormal heart rhythms or the need for a permanent pacemaker
• Leakage around the replacement valve
• Kidney injury
• Infection
• Valve-related complications

The Bottom Line

Severe aortic stenosis is a serious valve condition, particularly when it causes symptoms or begins to affect the heart's function. When valve replacement is indicated, TAVI offers a catheter-based way to replace the narrowed aortic valve without conventional open-heart surgery.

TAVI is now an important treatment option across a much broader range of patients than when it was first introduced. Under current European guidance, TAVI is recommended for anatomically suitable patients aged 70 years or older with a tricuspid aortic valve, while surgical replacement remains particularly important for younger patients and certain anatomical or clinical situations.

However, the best treatment cannot be determined by age or surgical risk alone. Valve anatomy, vascular access, overall health, life expectancy, associated heart conditions and the possibility of future valve procedures all need to be considered.

For this reason, the decision about TAVI versus surgical valve replacement is best made through a multidisciplinary Heart Team assessment. The goal is not simply to choose the least invasive procedure, but to select the treatment that provides effective relief from severe aortic stenosis while making sense for the patient's long-term heart health.