The aortic valve lies between the left ventricle of the heart and the aorta. The ventricles are the lower chambers of the heart. The left ventricle pumps oxygen-rich blood from the heart to the rest of the body through the aorta, a large blood vessel.

The aortic valve normally has three leaflets, called cusps, that open and close with each heartbeat. Stenosis is a narrowing of the valve that causes obstruction to blood flow. People with severe aortic valve stenosis are at a higher risk of sudden death.
How does it occur?

Aortic valve stenosis can be congenital. That is, it can run in families or may be due to some influence on the fetus during pregnancy. Congenital abnormality of the aortic valve may be the most common form of congenital heart disease. It's difficult to know for certain because the condition is hard to detect in young people. Males with this disease outnumber females 4 to 1.

Congenitally stenosed valves are thickened. Their cusps may be fused, or stuck together. The cusp fusion prevents normal opening of the valve. Abnormal blood flow patterns through the opening may lead to a deposit of calcium in the valve. This condition, found particularly in adults, leads to the valve becoming even thicker and more rigid.

Degenerative aortic valve stenosis is the most common of the acquired types. This type of aortic valve stenosis is probably due to aging. It is most common in people over age 60. The valve neither opens nor shuts normally, and some backflow or leakage through the valve may occur.

Aortic valve stenosis can be caused by rheumatic fever, but it is rare. When it does occur, it is almost always associated with mitral valve disease. The mitral valve is the valve between the upper chamber (atrium) and the ventricle on the left side of the heart. In this case, calcium deposits in the aortic valve are common, as is backflow (regurgitation) of blood through the valve.

A rare form of aortic valve stenosis is found in some families who have a special form of high blood cholesterol. Occasionally, people with severe rheumatoid disease develop thickening of the valve that leads to stenosis.
What are the symptoms?

In the early stages of the disease, you will have no symptoms, but aortic valve stenosis almost always worsens with time. As the blockage of blood flow from the heart increases, your left ventricle has to work harder. The heart muscle compensates by getting larger and thicker. It may develop stiffness.

Eventually, the left ventricle can no longer adapt. The first symptom is usually shortness of breath with exertion. You may also have shortness of breath when you are awake. With more severe valve blockage, you may have fainting spells or periods of unconsciousness. You may also have chest pain.
How is it diagnosed?

Diagnosis is made by taking a history of your symptoms and doing a physical examination. Using a stethoscope, your doctor will be able to hear the characteristic heart murmur caused by the blocked valve. Other laboratory tests will help confirm the diagnosis. An electrocardiogram will show enlargement and thickening of the heart muscle. An echocardiogram uses ultrasound waves to make images of the heart and valves. A special portion of the ultrasound test, called the Doppler exam, measures the severity of the stenosis. Chest x-rays and a treadmill exercise test may be needed.
How is it treated?

In the early stages of the disease, you will need no treatment. You will, however, need to take antibiotics before dental or genitourinary procedures. The antibiotics help to prevent infection of the diseased valve. Routine visits to a doctor, once or twice a year, are recommended.

You must see your doctor more often when symptoms begin to appear. Cardiac catheterization is usually required. This minor surgical procedure measures blood flow and pressures within the heart and helps to decide when valve surgery is necessary. In adults, valve replacement surgery is preferred. Direct opening of the fused valve cusps usually works best for children.

For adults two types of artificial heart valves are available: mechanical and bioprosthetic. Mechanical valve replacements have an excellent record but require lifelong blood thinner medicine and have a higher risk for bleeding complications. Bioprosthetic valves are either specially treated pig valves or valves fashioned from special tissues found elsewhere in the body. They do not require long-term blood thinners, but they have more frequent structural breakdowns.