Aortic stenosis is a narrowing of the aortic valve in the heart. This restricts blood flow through the valve. The heart then needs to squeeze (contract) harder to pump blood into the aorta. Mild narrowing may not cause symptoms. More severe narrowing can cause symptoms and may lead to heart failure. Surgery to stretch or replace the valve may be needed.

The aortic valve lies between the left ventricle and the aorta. The aorta is the main artery that takes blood from the heart to the body.

Aortic stenosis means that when the aortic valve opens, it does not open fully. It is narrowed (stenosed) when it is open. Therefore, there is a partial restriction of blood flow from the left ventricle into the aorta.

CAUSES

Rheumatic fever
Rheumatic fever is a condition that sometimes occurs during an infection with a germ (bacterium) called the streptococcus. Your body makes antibodies to the bacterium to clear the infection. However, in some people the antibodies also attack various parts of the body, in particular the heart valves. Inflammation of a valve may develop.

Other causes of aortic stenosis are uncommon and include:

Some congenital heart problems. (A congenital condition is a condition that is present from birth.) It is then usually part of a complex heart deformity.
Infection of the valve (endocarditis).

What are the symptoms of aortic stenosis?
If the valve is only mildly narrowed (stenosed) you are not likely to have any symptoms.
If the narrowing becomes worse the left ventricle has to work harder to pump blood into the aorta. The wall of the ventricle becomes thickened (hypertrophied).

Symptoms that may then develop include:

Dizziness and faints (especially on exertion) due to the restricted blood supply.
Chest pain (angina) when you exert yourself. This occurs because of the increased need for oxygen by the thickened ventricle and because of reduced blood flow to the coronary arteries.
Irregular heartbeat which you may feel as the sensation of a ‘thumping heart’ (palpitations).

If the narrowing is severe the left ventricle may not function properly and you can develop heart failure.

This causes shortness of breath, tiredness and fluid build-up in various tissues of the body.

What are the possible complications of aortic stenosis?
Heart failure may become severe and life-threatening.
Infection of the valve (endocarditis) is an uncommon complication. Abnormal valves are more prone than normal valves to infection. Unless promptly treated, endocarditis can cause serious illness.

What are the treatments for aortic stenosis?
If the narrowing (stenosis) is mild and you have no symptoms then you may not need any treatment. If you develop symptoms or complications, various medicines may be advised to ease the symptoms.

However, surgery is usually advised in most cases when symptoms develop. This is because studies have shown that once symptoms develop, the average survival is two to three years if the valve remains narrowed.
With surgery, the outlook is very good.

Medication may be advised to help ease symptoms of heart failure if heart failure develops. For example:

Angiotensin-converting enzyme (ACE) inhibitors are medicines which help to reduce the amount of work the heart does and can ease symptoms of heart failure.

‘Water’ tablets (diuretics) usually help if you are breathless. They make the kidneys produce more urine. This gets rid of excess blood and fluid which, with heart failure, may build up in the lungs or other parts of the body.

Surgical treatments
An operation to fix aortic stenosis is a commonly done procedure. It has a very good chance of success. The possible options include the following:

An operation to widen the valve (valvotomy). This requires open heart surgery.

Valve replacement. This also requires open heart surgery. The replacement may be with a mechanical or a tissue valve. Mechanical valves are made of materials which are not likely to react with your body, such as titanium. Tissue valves are made from treated animal tissue, such as valves from a pig.

Stretching the stenosed valve (balloon valvuloplasty). This is an option that is sometimes considered. This does not require open heart surgery. A thin tube called a catheter is inserted into the main blood vessel in the top of the leg. It is passed up to the heart. The tip of the catheter is placed in the aortic valve opening. A balloon at the tip of the catheter is then inflated to stretch the narrowed valve.

However, for adult patients, balloon valvuloplasty tends to be used only in those who are unsuitable for valvotomy or valve replacement surgery. This is because the improvement in the flow across the valve (following balloon valvuloplasty) does not usually last for very long.

Valvotomy or valve replacement surgery tends to give better long-term results.
If you need surgery, a surgeon will advise on which is the best option for your situation.

What is the outlook (prognosis) for people with aortic stenosis?

Some cases are mild and cause no symptoms. If you develop symptoms they tend to become worse over the years.

Medication may ease symptoms but cannot reverse a narrowed (stenosed) valve. Surgery is normally advised if you develop symptoms.

Surgical treatment has greatly improved the outlook in most people who have more severe stenosis. Surgery to widen or to replace the valve has a very good success rate. The outlook is good if the valve is treated before the heart becomes badly damaged.

G Mohan