The pulmonary valve is a trileaflet valve that allows blood to flow from the right ventricle up into the pulmonary artery and on to the lungs. Pulmonary valve disease is rare, but includes pulmonary valve stenosis and absent pulmonary valve. Like other forms of heart valve disease, pulmonary disease is graded and can range from mild to severe.
Pulmonary Valve Stenosis
Pulmonary valve stenosis (or obstruction) is a narrowing or blockage of the pulmonary valve. The narrowing occurs when the leaflets do not form properly before birth or when they change shape or fuse together due to an infection (rheumatic fever) or scarring. The narrowing, which can also occur above and below the valve, decreases blood flow and allows blood to backup into the right ventricle. Severe pulmonary valve obstruction may lead to the development of heart failure, stroke, arrhythmias, or blood clots. Surgery to repair congenital pulmonary stenosis is usually performed when children are 3 to 5 years old. Patients may be asymptomatic until the disease becomes more serious. When symptoms appear, they may include a heart murmur, fatigue, shortness of breath, chest pain, fainting, and poor weight gain for infants.
Absent Pulmonary Valve
A rare congenital defect occurs when an infant is born with an absent or poorly formed pulmonary valve. It may be part of a rare syndrome called tetralogy of Fallot and is also associated with several other types of congenital and genetic defects. The absent pulmonary valve often has a poorly formed, small opening or annulus. This type of valve blocks blood flow and it leaks. A patient with an absent pulmonary valve usually has enlarged pulmonary branch arteries that pressure the bronchial tubes in the lungs and cause breathing problems. Other symptoms may include blue skin color, a heart murmur, coughing, rapid breathing, wheezing, and respiratory infections. This condition can be diagnosed in utero or shortly after birth. Absent pulmonary valve requires surgical repair as soon as breathing problems develop or within the first few months of life. It is a life-threatening condition that can cause serious complications.
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 (transthoracic or transesophageal), 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.
Medications may be used to treat the symptoms, but they cannot cure heart valve disease. Severe pulmonary stenosis is life-threatening, and when this occurs, the valve must be opened. This procedure, called a valvotomy, does not repair the valve; it only relieves the stenosis. It can be performed in either the cardiac catheterization laboratory or in the operating room. Pulmonary valve leakage is likely to develop after a valvotomy procedure, and if it does, the valve will eventually need to be replaced.
Most cardiovascular surgeons agree that valve repair is the preferred method of treatment. Surgically separating or shaving back valve leaflets (a commissurotomy) can eliminate pulmonary stenosis and improve blood flow. If the lesion is too severe to be repaired, the valve must be replaced. Replacement involves removing the defective valve and replacing it with a prosthetic valve. Prosthetic valves can be biological (made from human or animal tissue) or mechanical (made from materials such as plastic, carbon, or metal). Mechanical valves carry the risk of forming 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 have 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 do develop endocarditis.
Texas Heart Institute www.texasheartinstitute.com/HIC/Topics/Cond/vpulmon.cfm
Medline Plus www.nlm.nih.gov/medlineplus/ency/article/001096.htm
Medline Plus www.nlm.nih.gov/medlineplus/ency/article/007314.htm
American Heart Association www.americanheart.org/presenter/jhtml?identifier=11070