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Back to Cardiovascular Diseases
Aortic
valve
regurgitation
Updated: September 19, 2006
Causes and risk factors
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 in which 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 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). About 2% of boys
and 1% of girls are born with this defect. Other causes of aortic
regurgitation include bacterial infection of a heart valve (infective endocarditis) and injury.
Basically, any condition that damages a valve can cause or predispose
regurgitation. Some of the more common ones include:
- Ankylosing spondylitis, a spinal disorder
- Aortic dissection and aortic aneurysm
- Congenital heart defects that are present at birth, such as
unicuspid or bicuspid aortic valve
- High blood pressure
- Infective endocarditis, an infection in the valves or lining of
the heart
- Marfan syndrome, an inherited disease of connective tissues
- Reiter syndrome, an arthritic disorder that affects adult males,
which is now rare
- Rheumatic fever, a disease that can cause arthritis and heart
problems
- Rheumatoid arthritis, which also causes joint pain and swelling
- Syphilis, especially congenital syphilis
- Systemic lupus erythematosus, an autoimmune disorder in which
the person creates antibodies against his or her own tissues
- Ehlers - Danlos syndrome
- Pseudoxanthoma elasticum
- Deterioration of the valve with age.
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Pathogenesis
The ventricles pump blood in a forward direction from the heart to
the aorta. Normally the aortic valve prevents backflow of blood to the
heart when the heart relaxes after pumping. Back flow of the blood to
the ventricle during relaxation leads to a subsequent increase in left
ventricular volume. This leads to an increase in systolic blood pressure
which is accompanied by reflex peripheral vessel dilatation which lowers
the diastolic blood pressure resulting in a wide pulse pressure. The
lowering of the diastolic blood pressure reduces flow of blood to the
coronaries which relies on diastolic pressure. The resultant volume
overload eventually leads to heart failure.
A leak may develop gradually (over months or years) or quickly (over
hours or days). Aortic regurgitation may result when the aorta enlarges,
often because of high blood pressure. When the aorta is enlarged, the
valve may not close completely. As a result, blood leaks backward
through the valve into the heart.
Aortic regurgitation may worsen if a person has a heart infection or
aortic dissection. The function of the left heart chamber may
deteriorate quickly within a few weeks or months. Chronic regurgitation
usually progresses slowly. It can cause severe congestive heart failure,
or CHF.
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