Every time it beats, blood flows in, through, and out of the heart, moving approximately 100 gallons (379 liters) through the body each hour. Heart valves control the one-way blood flow, opening and closing with each heartbeat. Anatomic factors, hemodynamic factors, and pressure changes cause the valves to open and close at the right times. The valves have flap-like cusps or leaflets that prevent the backflow of blood.
The four heart valves are the:
Blood returns from the body and collects in the right atrium. From there, it travels through the tricuspid valve into the right ventricle. The right ventricle pumps the blood through the pulmonary valve into the lungs. The blood becomes oxygenated in the lungs. Oxygen-rich blood returning from the lungs flows into the left atrium. The blood then travels through the mitral valve into the left ventricle. The left ventricle pumps blood through the aortic valve and on to the rest of the body.
Two types of problems disrupt blood flow through the heart valves: regurgitation or stenosis.
Regurgitation, which is also called insufficiency or incompetence, results when a valve does not close properly and causes blood to leak backwards through the valve. Too much regurgitation causes an insufficient amount of blood to be traveling forward, and the heart tries to compensate by working harder. In time, the heart becomes enlarged and eventually begins to fail.
Stenosis is a narrowing of the valve’s anatomic structure, and it causes the leaflets to not open wide enough. Only a small amount of blood can flow through a stenotic valve. Stenosis occurs when the leaflets thicken, stiffen, or fuse together. Because of the narrowed valve, the heart must work harder to move blood through the body.
What Causes Valve Disease?
Before the widespread use of antibiotics, rheumatic fever was the main cause of heart valve disease. Today, the cause is most likely linked to one of the following:
- The aging process weakens valve tissue (myxomatous degeneration).
- Calcium is deposited, builds up, and thickens the valve (calcific degeneration).
- A congenital defect creates an irregularly shaped or narrowed valve.
- The anti-obesity medicines fen-phen or Redux have damaged the valve.
- Infective endocarditis damages the valve.
- Coronary artery disease or a heart attack adversely affects the valve.
Symptoms depend on the patient and the location, type, and severity of the valve disease. Some patients experience no symptoms. In other cases, valve disease may take its toll over many years. In time, untreated valve disease can lead to congestive heart failure, cardiomyopathy, arrhythmia, or blood clots.
Heart valve disease is diagnosed by listening to the heart with a stethoscope; diseased heart valves make distinct clicking sounds or murmurs. Other diagnostic tests that are used to determine the underlying cause, complexity, and severity of heart valve disease include a chest x-ray, blood tests, an echocardiogram, electrocardiography (ECG) or Holter monitoring, exercise stress testing, electrophysiology (EP) studies, cardiac catheterization, and diagnostic imaging scans, such as computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET). A careful and complete diagnostic workup will help determine the timing and composition of the treatment plan.
Treatment for heart valve disease depends on which valve(s) is/are involved, and the type and severity of the diagnosis. Asymptomatic patients may not need treatment. In some cases, careful monitoring is all that is needed.
Medicine cannot cure heart valve disease, but some types of medicine (digitalis, diuretics, anticoagulants, beta blockers, calcium channel blockers, and ACE inhibitors) may ease the pain or symptoms, reduce the workload on the heart, or regulate an associated arrhythmia.
If the symptoms caused by the valve disease worsen, become difficult to manage, or if medicine no longer relieves symptoms, a percutaneous transcatheter intervention may be needed. Balloon valvuloplasty is an interventional procedure that may be used to open narrowed heart valves. The procedure involves sending an extremely small inflatable balloon through a peripheral artery into the heart. The balloon is placed inside the valve and inflated to re-open the narrowed opening. New research is currently underway to use this type of percutaneous procedure to remove a damaged valve and then “launch” a replacement valve into its place.
When needed for the most complex or severe cases, open heart surgery is used to treat valve disease. Valves can be repaired or replaced. Repair may involve opening a narrowed valve by removing calcium deposits, reinforcing a valve that doesn’t close properly, or reconstructing the anatomy of a valve to restore normal function. Repair is also used to treat congenital valve defects. Replacement is used to treat a diseased valve that cannot be repaired. It involves removing a defective heart valve and replacing it with a prosthetic valve. Prosthetic valves can be mechanical (made from materials such as plastic, carbon, or metal) or biological (made from human or animal tissue). Mechanical valves carry the risk of developing a blood clot on the new valve, so patients with mechanical heart valves must take blood-thinning medicine for the rest of their lives to prevent this complication.
Preventative Antibiotics and Heart Valve Disease
Patients with heart valve disease who have an abnormal heart or who’ve had heart surgery risk developing endocarditis. The American Heart Association no longer recommends taking routine antibiotics before certain dental or surgical procedures except for people at the highest risk for bad outcomes if they develop endocarditis.
Texas Heart Institute www.texasheartinstitute.com/HIC/Topics/Cond/valvedis.cfm
Mayo Clinic www.mayoclinic.org/heart-valve-disease/index.html
American Heart Association www.americanheart.org/presenter.jhtml?identifier=4598