Heart Valve Diseases




Valve problems can be present at birth or caused by infections, heart attacks, or heart disease or damage. Some valve problems are minor and do not need treatment. Others might require medicine, medical procedures or surgery to repair or replace the valve.

Heart has four valves. Normally, these valves open to let blood flow through or out of your heart, and then shut to keep it from flowing backward. But sometimes they don't work properly. What can happen?

  • Blood can leak back through the valve in the wrong direction, which is called regurgitation
  • One of the valves, the mitral valve, sometimes has "floppy" flaps and doesn't close tightly. This is called mitral valve prolapse, and it's one of the most common heart valve conditions. Sometimes it causes regurgitation
  • When the valve doesn't open enough, which blocks blood flow, it is called stenosis
The heart valves can malfunction either by leaking (termed regurgitation) or by not opening adequately and thus partially blocking the flow of blood through the valve (termed stenosis). Either problem can greatly interfere with the heart's ability to pump blood. Sometimes a valve has both problems. Faulty valves generally create murmurs and other abnormal heart sounds that a doctor can hear with a stethoscope; faulty valves can be identified by using echocardiography. Often, minor degrees of regurgitation are not detected with a stethoscope but are detected during an echocardiogram. Doctors often regard this as a normal finding.

Heart valve disease

Valve disease occurs when your heart's valves do not work correctly. This can be caused by valvular stenosis or valvular insufficiency.

In valvular stenosis, the tissues forming the valve leaflets become stiffer, narrowing the valve opening and reducing the amount of blood that can flow through it. If the narrowing is mild, the overall functioning of the heart may not be reduced. However, the valve can become so narrow (stenotic) that heart function is reduced, and the rest of the body may not receive adequate blood flow.

Another condition, called valvular insufficiency (or regurgitation, incompetence, "leaky valve"), occurs when the leaflets do not close completely, letting blood leak backward across the valve. This backward flow is referred to as “regurgitant flow.”

A narrowed or “stenotic” valve requires the heart to pump harder, which can strain the heart and reduce blood flow to the body.

A regurgitant (incompetent, insufficient, or leaky) valve does not close completely, letting blood move backward through the valve.

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Causes

There are many types of valve disease .Valve disease can be congenital (present at birth) or may be acquired later in life. Sometimes the cause of valve disease may be unknown.

Congenital valve disease is an abnormality that develops before birth. It may be related to improper valve size, malformed leaflets, or an irregularity in the way the leaflets are attached. This most often affects the aortic or pulmonic valve.

Bicuspid aortic valve disease is a congenital valve disease that affects the aortic valve. Instead of the normal three leaflets or cusps, the bicuspid aortic valve has only two. Without the third leaflet, the valve may be:
  • stenotic - stiff valve leaflets that can not open or close properly
  • leaky - not able close tightly
This occurs more frequently in some family members. About 1/4 of patients may have some enlargement of the aorta above the valve. Bicuspid aortic valve disease affects about 2 percent of the population.

Acquired valve disease includes problems that develop with valves that were once normal. These may involve changes in the structure of your valve or infection.

Infection

Infective endocarditis and rheumatic fever are the two common infections that cause valve disease

Rheumatic fever causes a common type of valve disease, rheumatic heart disease.

It causes
  • the heart valve leaflets to become inflamed
  • may cause the leaflets to stick together and become scarred, rigid, thickened and shortened
  • may cause one or more of the valves (most commonly the mitral valve) to become stenotic (narrowed) or leaky
Rheumatic fever is usually caused by an untreated streptococcal infection, such as strep throat. The use of penicillin to treat strep throat can prevent this disease. Rheumatic fever occurs most often in children aged five to fifteen, but symptoms of valve disease may not be seen for years. The valve itself is not infected in rheumatic fever. Antibodies developed by the body to fight the infection react with the heart valves, causing inflammation and eventual scarring.

Endocarditis is a major infection and can be life-threatening. It occurs when germs (especially bacteria) enter your blood stream and attach to the surface of your heart valves. With endocarditis:
  • germs attack the heart valve, causing growths on the valve, holes in the valve or scarring of the valve tissue
  • may cause the valve to leak or become stenotic (narrowed)
The germs can enter your blood stream during:
  • dental procedures
  • surgery
  • intravenous (IV) drug use
  • severe infections
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Mitral valve prolapse

Mitral valve prolapse (MVP) is a type of myxomatous valve disease. MVP causes the leaflets of the mitral valve to flop back into the left atrium during the heart's contraction. MVP also causes the tissues of the valve to become abnormal and stretchy, causing the valve to leak.

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Fibro-calcific degeneration

Fibro-calcific degeneration most commonly affects the aortic valve. It most often occurs in adults over the age of 65. This condition can be compared to atheroma in coronary artery disease. The valve leaflets become fibrotic (thickened) and calcified (hardened), producing a narrowed valve opening. Risk factors for this type of valve disease include: Page Top

Dilatation of the valve annulus

Dilatation of the valve annulus is a widening or stretching of the annulus. This causes the leaflets to lack support and not close tightly

Dilatation may occur when the heart muscle is damaged due to:
  • a heart attack (heart muscle injury)
  • cardiomyopathy (weakened heart muscle)
  • heart failure
  • advanced stages of high blood pressure
  • syphilis
  • inherited disorders (such as Marfan syndrome)
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Surgery

Surgery is the most invasive option for the treatment of valve disease. During surgery, valves may either be repaired or replaced.

Repair may involve opening a narrowed valve by removing calcium deposits or reinforcing a valve that doesn't close properly. Repair may also be used to treat congenital defects and defects of the mitral valve.

Replacement is used to treat any diseased valve that cannot be repaired. It involves removing a defective valve and stitching in its place a prosthetic valve. Prosthetic valves can either be mechanical (made from materials such as plastic, carbon, or metal) or biological (made from human or animal tissue). Mechanical valves increase the risk of blood clots forming on the new valve. Patients with mechanical heart valves will need to take blood-thinning medicines for the rest of their lives.

Valve surgery is an open heart technique. This means that surgeons use a heart-lung machine, because the heart must stop beating for a short time during surgery.

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Information obtained from National Institute of Health
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