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.

Understanding the heart
The heart has four chambers – two atria and two ventricles. The walls of these chambers are mainly made of special heart muscle. During each heartbeat both of the atria squeeze (contract) first to pump blood into the ventricles. Then both ventricles contract to pump blood out of the heart into the arteries. There are one-way valves between the atria and ventricles, and between the ventricles and the large arteries coming from the heart. The valves make sure that when the atria or ventricles contract, the blood flows in the correct direction.

[color=#4000FF]What is the aortic valve and what is aortic stenosis?[/color]
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. The aortic valve has three flaps (cusps). Blood flows through the valve when the left ventricle squeezes (contracts) at the early part of the heartbeat. When the left ventricle relaxes, the aortic valve closes. Then the mitral valve opens to allow more blood into the ventricle ready for the next heartbeat.

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. Basically, the more narrowed the valve, the less blood that can get through, the more severe the problem is likely to be.

What are the causes of aortic stenosis?
Age-related calcification of the valve
This is a common cause. Deposits of calcium build up in the valve in some older people. It is not clear why this happens. This calcification makes the valve stiff and open less easily. It can be mild and cause little narrowing. However, in time it can become more severe. About 1 in 20 people aged over 65 have some degree of this type of aortic stenosis.

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. This can cause permanent damage and lead to thickening and scarring years later.

Other causes
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.

An abnormality of the tissues just above or just below the valve. This may cause a narrowing and restrict blood flow, and cause problems identical to stenosis of the valve.

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.

How is aortic stenosis diagnosed?
A doctor may hear a heart murmur or other abnormal noises when listening with a stethoscope. Murmurs and noises are due to blood passing through abnormal valves, or to abnormal movement of valves. Aortic stenosis causes typical murmurs and noises.
A chest X-ray may show some calcification around the aortic valve.

A heart tracing (an electrocardiogram, or ECG) can show that the left ventricle is thickened.

An ultrasound scan of the heart (an echocardiogram) can confirm the diagnosis. This is an ultrasound scan of the heart.

Cardiac catheterisation is sometimes done to assess the severity of the stenosis.

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, with surgery, the outlook is very good.

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

Surgical treatments
An operation to fix aortic stenosis is a commonly done procedure. It has a very good chance of success.
If you need surgery, a surgeon will advise on which is the best option for your situation.

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.

NB: quite often many people who are being assessed for various types of surgery of the body , are checked medically or for Anaesthesia , the murmur is incidentally picked up.

Dr G Mohan