Narrowing of the aortic valve, reducing the flow of blood into the circulation
The aortic valve separates the left lower chamber (left ventricle) of the heart and the main artery of the body, the aorta. The valve opens to allow blood to flow out of the heart. In aortic stenosis, the opening of the valve is narrowed, reducing the flow of blood through it. The heart then has to pump harder to compensate. Aortic stenosis is the most common valve disorder requiring valve replacement in the UK.
In young people living in developed countries, aortic stenosis is usually the result of a heart abnormality that is present at birth (see Congenital heart disease). In elderly people, aortic stenosis is often caused by calcium deposits on the aortic valve, which naturally build up over time. Rheumatic fever was once a common cause of aortic stenosis. However, rheumatic fever is now rare in developed countries, mainly due to the use of effective antibiotics.
In mild cases of aortic stenosis, there are often no symptoms. In some cases of mild stenosis, tiredness may be the only symptom. Other symptoms may develop in more severe cases, such as:
Dizziness and fainting.
Chest pain during exertion.
If the opening through the aortic valve is very narrow, the flow of blood to the coronary arteries that supply blood to the heart muscle is reduced. This will eventually lead to breathlessness due to chronic heart failure. Abnormal heart rhythms may also develop (see Arrhythmias), and infection of the valves is more likely.
Often, mild aortic stenosis is detected during a routine examination. If your doctor suspects that you have aortic stenosis, he or she may arrange for echocardiography to image the interior of the heart, including the aortic valve. You may also have a chest X-ray because, if there is stenosis, calcium deposits on the valve may be visible on the X-ray. The severity of stenosis can be assessed by a procedure called cardiac catheterization, in which a flexible catheter is inserted into an artery in the arm or groin and passed into the heart. A small device attached to the catheter then measures the pressures on either side of the valve.
Mild stenosis is frequently treated with drugs such as diuretics, which relieve breathlessness by removing excess fluid from the lungs. However, a heart valve replacement is often needed eventually. If you have a certain type of congenital aortic stenosis, you may be advised to have a balloon valvuloplasty, in which a balloon is inflated in the valve to widen it. The outlook is good if you are given treatment before the heart muscle becomes badly damaged. A stenotic or replacement aortic valve is more susceptible to infection (see Infective endocarditis) than a normal valve. Your doctor will advise you to maintain good oral hygiene to reduce the risk of infection. You will also be told how to recognize symptoms of infective endocarditis so that treatment can be given promptly if it does develop.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.