Aortic regurgitation (aortic incompetence, aortic insufficiency) is leakage of blood back through the aortic valve each time the left ventricle relaxes.

• Rheumatic fever and syphilis are the most common causes.
• Aortic regurgitation causes no symptoms unless heart failure develops.
• Doctors suspect the diagnosis because of physical examination findings, and they use echocardiography to confirm the diagnosis.
• The damaged heart valve must be replaced surgically.

As the left ventricle relaxes to fill with blood from the left atrium, blood leaks backward from the aorta into the left ventricle, increasing 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.

Cause

Rheumatic fever and syphilis used to be the most common causes of aortic regurgitation in North America, Australasia, 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. Aside from these infections, the most common causes of severe aortic regurgitation are weakening of the valve's usually tough, fibrous tissue due to myxomatous degeneration (a hereditary connective tissue disorder in which the valve gradually becomes floppy); degeneration of the valve due to unknown factors; aortic aneurysms; and aortic dissection. Common causes of mild aortic regurgitation are severe high blood pressure and a birth defect in which the aortic valve consists of two cusps (bicuspid valve) instead of the usual three (tricuspid valve—see Birth Defects: Aortic Valve Stenosis). About 2% of boys and 1% of girls are born with this defect. Other causes of aortic regurgitation include bacterial infection of the valve (infective endocarditis) and injury.

Symptoms and Diagnosis

Mild aortic regurgitation produces no symptoms 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, causing blood pressure to decrease sharply.

Doctors usually suspect the diagnosis based on the results of a physical examination (such as the collapsing pulse and characteristic heart murmur) and an enlarged heart seen on an x-ray. Electrocardiography (ECG) may show signs of an enlarged left ventricle. Echocardiography can show the faulty valve and help doctors determine how severe regurgitation is and whether heart valve replacement surgery is needed. Coronary angiography is performed in older people before surgery because about 20% of people with aortic regurgitation also have coronary artery disease.

Treatment

Unless aortic regurgitation is mild, surgery is ultimately almost always required. Drug treatment is not especially effective in slowing the progression of heart failure and does not eliminate the need for timely valve replacement, but various drugs may be used to control symptoms prior to surgery. The damaged valve should be surgically replaced with an artificial valve before the left ventricle becomes irreversibly damaged and heart failure becomes too severe. Usually, echocardiography is performed periodically to determine how rapidly the left ventricle is enlarging, so that surgery can be scheduled at an appropriate time.

People with aortic regurgitation, even when mild, are given antibiotics before surgical, dental, or medical procedures (see Which Procedures Require Preventive Antibiotics?) to reduce the risk of infection of the damaged heart valve.

Last full review/revision May 2006 by Paul H. Tanser, MD