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Diseases and Conditions
Aortic valve stenosis
From MayoClinic.com
Special to CNN.com Introduction Aortic valve stenosis — or aortic stenosis — is a condition in which the heart's aortic valve narrows. This narrowing prevents the valve from opening fully, which obstructs blood flow from your heart into your aorta and onward to the rest of your body. Aortic valve stenosis usually results in an abnormal heart sound (heart murmur) that doctors can hear with a stethoscope. When the aortic valve is obstructed, your heart needs to work harder to pump blood to your body. Eventually your heart muscle becomes thicker because it has to pump harder due to the obstruction. In addition, your heart can pump only a limited amount of blood — and can't provide the increase in blood flow you need for activities such as exercise. Several factors, including aging, can damage the aortic valve and lead to aortic valve stenosis. Some babies are even born with a defective aortic valve. If you have severe aortic valve stenosis, you'll usually need surgery to replace the valve. Left unchecked, aortic valve stenosis can lead to serious heart problems. Signs and symptoms Aortic valve stenosis ranges from mild to severe. Signs and symptoms typically develop when narrowing of the valve is severe and can include:
When your aortic valve narrows, your heart can't pump blood as efficiently. Because your heart has to work harder to pump blood through a narrowed valve, over time the heart muscle may weaken, leading to congestive heart failure. Signs and symptoms of congestive heart failure include fatigue, shortness of breath, and swollen ankles and feet. Aortic valve stenosis may not produce warning signs right away, making it difficult to detect at first. Aortic valve stenosis is often discovered during a routine physical when a doctor hears a heart murmur. This murmur may occur long before other signs and symptoms develop. Depending on the amount of narrowing, an infant or child with aortic valve stenosis may have no symptoms, may tire easily or may have chest pain with vigorous physical activity. Causes Aortic valve stenosis obstructs the way blood normally flows through your heart and its valves. A number of factors can cause this disorder. Your heart, the center of your circulatory system, consists of four chambers. The two upper chambers, the atria, receive blood. The two lower chambers, the ventricles, pump blood. Blood returning to your heart enters the right upper chamber (right atrium). From there, blood empties into the right ventricle underneath. The right ventricle pumps blood into your lungs, where blood is oxygenated. Blood from your lungs then returns to your heart, but this time to the left side — to the left upper chamber (left atrium). Blood then flows into the left ventricle underneath — your heart's main pump. With each heartbeat, the left ventricle forces blood through the aortic valve into the aorta, your body's largest artery. Blood flows through your heart's chambers, aided by four heart valves. These valves open and close to let blood flow in only one direction through your heart:
The aortic valve — your heart's gateway to the aorta — consists of three tightly fitting, triangular-shaped flaps of tissues called leaflets. These leaflets connect to the aorta through a ring called the annulus. Heart valves open like a one-way gate. The leaflets of the aortic valve are forced open as the left ventricle contracts and blood flows into the aorta. When all of the blood has gone through the valve and the left ventricle has relaxed, the leaflets swing closed to prevent the blood that has just passed into the aorta from flowing back into the left ventricle. A defective heart valve is one that fails either to open or close fully. When a valve doesn't close tightly, blood can leak backward. This backward flow through a valve is called regurgitation. When a valve narrows, the condition is called stenosis. Various causes
Aortic valve stenosis — of any cause — can be a serious condition because it can weaken the heart. If the aortic valve is narrowed, the left ventricle has to work harder to pump a sufficient amount of blood into the aorta and onward to the rest of your body. In response, the left ventricle may thicken and enlarge. At first these adaptations help the left ventricle pump blood with more force. But eventually these changes weaken the left ventricle — and your heart overall. Risk factors Aortic valve stenosis is often not preventable. Some people are born with an already narrowed aortic valve or develop aortic valve stenosis later in life because they were born with a bicuspid aortic valve — one with two flaps (leaflets) instead of three. A bicuspid aortic valve is a major risk factor for aortic valve stenosis. Aortic valve stenosis also may be related to age and the buildup of calcium deposits on heart valves or a history of rheumatic fever. When to seek medical advice Aortic valve stenosis most commonly affects adults, but can occur in children. Infants and children with the condition may experience symptoms similar to those of adults. If you or your child experiences such signs or symptoms, see a doctor — especially if you or your child has a known heart problem. Screening and diagnosis As part of a routine physical, your doctor uses a stethoscope to listen to your heart. He or she is listening for, among other things, an abnormal heart sound (heart murmur). If your doctor discovers a heart murmur, he or she will discuss it with you. Many heart conditions, including aortic valve stenosis, can produce a heart murmur. In the case of aortic valve stenosis, the heart murmur results from turbulent blood flow through the narrowed valve. Diagnostic tests
These tests and others help your doctor determine how narrow or tight your aortic valve may be and how well your heart is pumping. Once aortic valve stenosis is discovered, your doctor will either recommend treatment or suggest careful monitoring. Complications Aortic valve stenosis puts you at risk of endocarditis. Endocarditis is an infection of your heart's inner lining — the endocardium. This membrane lines the four chambers and four valves of your heart. Typically, the infection involves one of the heart valves, especially if it's already damaged. If the aortic valve is narrowed, it's more prone to infection than a healthy valve is. You can develop endocarditis when bacteria from another part of your body spread through your bloodstream and lodge in your heart. If you have aortic valve stenosis, it's recommended that you take antibiotics before certain dental or medical procedures that may increase the likelihood of bacteria entering your bloodstream and causing an infection in your heart. Left unchecked, aortic valve stenosis can lead to congestive heart failure. Congestive heart failure is a serious condition in which your heart is unable to pump sufficient blood to meet your body's needs. Severe aortic valve stenosis ultimately can be life-threatening. The condition can lead to irregular heart rhythms (arrhythmias) and cardiac arrest. Treatment Medications sometimes can ease symptoms of aortic valve stenosis. However, the only way to eliminate aortic valve stenosis is surgery to repair or replace the valve and open up the passageway. However, surgery isn't always needed right away. If tests reveal that you have mild to moderate aortic valve stenosis and you have no symptoms, there's generally no need for immediate valve surgery. Instead, your doctor will talk with you about scheduled checkups to carefully monitor the valve so that surgery can be done at the appropriate time. Your doctor will also prescribe antibiotics before dental work to reduce the risk of endocarditis. The same approach is usually taken with infants and children with mild to moderate aortic valve stenosis. In general, the appropriate time for surgery is when narrowing becomes severe and signs and symptoms develop. If at any point you notice signs and symptoms associated with aortic valve stenosis, let your doctor know so that your valve can be evaluated. Some people never develop severe aortic valve stenosis, so they never need surgery. For others, the condition progresses and surgery is necessary. Medications If you have aortic valve stenosis, your doctor will recommend that you take antibiotics before certain dental or medical procedures, to prevent the heart infection endocarditis. Surgery
Aortic valve stenosis can be treated effectively with surgery. However, you may still be at risk of irregular heart rhythms even after you've been treated for aortic valve stenosis. You may need to take medications to lower that risk. Prevention Some possible ways to prevent aortic valve stenosis include:
Once you know that you have aortic valve stenosis, your doctor may recommend that you limit strenuous activity to avoid overworking your heart. If you're a woman of childbearing age with aortic valve stenosis, discuss pregnancy and family planning with your doctor before you become pregnant. Your heart works harder during pregnancy. How a heart with aortic valve stenosis tolerates this extra work depends on the degree of stenosis and how well your heart pumps. Should you become pregnant, you'll need evaluation by your cardiologist and obstetrician throughout your pregnancy, labor and delivery, and after delivery. September 23, 2005 |