What Causes Heart Valve Disease?
Heart conditions and other disorders, age-related
changes, rheumatic fever, and infections can cause acquired heart valve
disease. These factors change the shape or flexibility of once-normal
valves.
The cause of congenital heart valve defects isn't
known. These defects occur before birth as the heart is forming. Congenital
heart valve defects can occur alone or with other types of
congenital
heart defects.
Heart Conditions and Other Disorders
Heart valves can be stretched and distorted by:
- Damage and scar tissue due to a
heart
attack or injury to the heart.
- Advanced
high
blood pressure and
heart
failure. These conditions can enlarge the heart or the main arteries.
- Narrowing of the aorta due to the buildup of a
fatty material called plaque (plak) inside the artery. The aorta is the main
artery that carries oxygen-rich blood to the body. The buildup of plaque inside
an artery is called
atherosclerosis
(ath-er-o-skler-O-sis).
Age-Related Changes
Men older than 65 and women older than 75 are prone
to developing calcium and other deposits on their heart valves. These deposits
stiffen and thicken the valve flaps and limit blood flow (stenosis).
The aortic valve is especially prone to this
problem. The deposits resemble those seen in the narrowed and hardened blood
vessels of people who have atherosclerosis. Some of the same processes may
cause both atherosclerosis and heart valve disease.
Rheumatic Fever
Some people have heart valve disease due to
untreated strep throat or other infections with strep bacteria, which progress
to rheumatic fever.
When the body tries to fight the strep infection,
one or more heart valves may be damaged or scarred in the process. The aortic
and mitral valves are most often affected. Symptoms due to heart valve damage
often don't appear until many years after recovery from rheumatic fever.
Today, most people with strep infections are treated
with antibiotics before rheumatic fever develops. It's very important to take
the entire amount of antibiotics your doctor prescribes for strep throat, even
if you feel better.
Heart valve disease due to rheumatic fever mainly
affects older people who had strep infections before antibiotics were
available. It also affects people from developing countries, where rheumatic
fever is more common.
Infections
Common germs that enter through the bloodstream and
get carried to the heart can sometimes infect the inner surface of the heart,
including the heart valves. This rare, but sometimes life-threatening infection
is called
endocarditis (EN-do-kar-DI-tis).
The germs can enter the bloodstream through needles,
syringes, or other medical devices and through breaks in the skin or gums.
Usually the body's defenses fight off the germs and no infection occurs.
Sometimes these defenses fail, which leads to endocarditis.
Endocarditis can develop in people who already have
abnormal blood flow through a heart valve due to congenital or acquired heart
valve disease. The abnormal blood flow causes blood clots to form on the
surface of the valve. The blood clots make it easier for germs to attach to and
infect the valve.
Endocarditis can worsen existing heart valve
disease.
Other Conditions and Factors Linked To Heart Valve
Disease
A number of other conditions and factors are
sometimes linked to heart valve disease. However, it's often unknown how these
conditions actually cause heart valve disease.
- Systemic lupus erythmatosis (SLE). SLE and other
immune diseases can affect the aortic and mitral valves.
- Carcinoid syndrome. Tumors in the digestive tract
that spread to the liver or lymph nodes can affect the tricuspid and pulmonary
valves.
- Metabolic disorders. Relatively uncommon
diseases, such as Fabry disease and hyperlipidemia, can affect the heart
valves.
- Diet medicines. The use of fenfluramine and
phentermine ("fen-phen") has sometimes been linked to heart valve problems.
These problems typically stabilize or improve after the medicine is stopped.
- Radiation therapy. Radiation therapy to the chest
area can cause heart valve disease. This therapy is used to treat cancer. Heart
valve disease due to radiation therapy may not cause symptoms for as many as 20
years after the therapy ends.
- Marfan
syndrome. Congenital disorders, such as Marfan syndrome, and other
connective tissue disorders mainly affect the structure of the body's main
arteries. However, these conditions also can also affect the heart valves.
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