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.