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Back to Cardiovascular Diseases
Aortic
valve
regurgitation
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
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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