Aortic regurgitation is leakage of blood back through the aortic valve each time the left ventricle relaxes.
- Aortic regurgitation is due to deterioration of the aortic valve and the surrounding aortic root (base of the aorta—the blood vessel transporting blood from the heart to the rest of the body).
- The deterioration sometimes occurs in a person with a bicuspid aortic valve but may also result from a bacterial infection of the valve or rheumatic fever.
- Aortic regurgitation causes no symptoms unless heart failure develops.
- Doctors make the diagnosis because of physical examination findings, and they use echocardiography to confirm the diagnosis and measure its severity.
- The damaged heart valve must be monitored periodically so that it can be replaced or repaired surgically once the leakage becomes significant and the heart starts to fail.
(See also Overview of Heart Valve Disorders.)
The aortic valve is in the opening between the left ventricle and the ascending aorta (the large artery leading from the heart). The aortic valve opens as the left ventricle contracts to pump blood into the aorta. When the aortic valve does not close completely, blood leaks backward from the aorta into the left ventricle as the left ventricle relaxes to fill with blood from the left atrium. The backward leakage of blood, termed regurgitation, increases the volume and pressure of blood in the left ventricle. As a result, the amount of work the heart has to do increases. To compensate, the muscular walls of the ventricles thicken (hypertrophy), and the chambers of the ventricles enlarge (dilate). Eventually, despite this compensation, the heart may be unable to meet the body's need for blood, leading to heart failure, with fluid accumulation in the lungs.
Causes of Aortic Regurgitation
Aortic valve regurgitation may develop suddenly (acute) or gradually (chronic).
The most common causes of acute aortic regurgitation are
- Infection of the valve (infective endocarditis)
- A tear in the lining of the aorta (aortic dissection)
The most common causes of chronic aortic regurgitation are
- Spontaneous weakening of the valve or the ascending aorta (particularly with a birth defect in which the aortic valve is bicuspid with only two, instead of three, cusps)
- Rheumatic fever
Rheumatic fever and syphilis used to be the most common causes of aortic regurgitation in North America and Western Europe, where both disorders are now rare because of the widespread use of antibiotics. In regions where antibiotics are not widely used, aortic regurgitation due to rheumatic fever or syphilis is still common.
About 1% of babies have a bicuspid aortic valve, but it commonly does not cause problems until adulthood.
Symptoms of Aortic Regurgitation
Mild aortic regurgitation causes no symptom other than a characteristic heart murmur that can be heard with a stethoscope each time the left ventricle relaxes. People with severe regurgitation may develop symptoms when heart failure results.
Heart failure causes shortness of breath during exertion. Lying flat, especially at night, makes breathing difficult. Sitting up allows backed-up fluid to drain out of the upper part of the lungs, restoring normal breathing. About 5% of people with aortic regurgitation have chest pain due to an inadequate blood supply to the heart muscle (angina), especially at night.
The pulse, sometimes called a collapsing pulse, is momentarily strong, then disappears quickly because the blood leaks backward through the aortic valve into the heart, causing blood pressure to decrease sharply.
Diagnosis of Aortic Regurgitation
- Physical examination
The diagnosis is based on the results of a physical examination (such as the collapsing pulse and characteristic heart murmur) and confirmed by echocardiography. Echocardiography also shows the severity of the regurgitation and whether the heart muscle has been affected. If echocardiography results suggest the aorta is widened, doctors often do computed tomography (CT) or magnetic resonance imaging (MRI) to detect aortic dissection.
Chest x-ray and electrocardiography (ECG) usually show signs of an enlarged heart. Coronary angiography is done before surgery because about 20% of people with severe aortic regurgitation also have coronary artery disease. First-degree relatives (that is, parents, siblings, or children) of people with a bicuspid valve should also be screened because 20 to 30% will be similarly affected.
Treatment of Aortic Regurgitation
- Valve repair or replacement
Drug treatment is not especially effective in slowing the progression of heart failure and does not eliminate the need for timely valve repair or replacement.
Echocardiography is done periodically to determine how rapidly the left ventricle is enlarging, which will help doctors determine when surgery should be done. The damaged valve should be surgically repaired or replaced with an artificial valve before the left ventricle becomes irreversibly damaged.
People who have had a valve replacement are given antibiotics before surgical, dental, or medical procedures (see Table: Examples of Procedures That Require Preventive Antibiotics in the United States*) to reduce the risk of infection of the heart valve.