The pulmonary valve connects the right ventricle and the pulmonary artery. When the heart squeezes, the valve opens, allowing blood to pass from the right ventricle to the pulmonary artery. When the heart relaxes, the valve closes, preventing backflow of blood into the heart. Pulmonary valve stenosis refers to a condition in which the valve is abnormally narrowed. Pulmonary valve stenosis is a congenital heart defect, in other words, a birth defect of the heart. Congenital heart defects are the most common form of birth defects, occurring in approximately 1 in 150 individuals. Pulmonary valve stenosis is one of the more common congenital heart defects; the overall incidence is 0.5-1 per 1000. The cause of pulmonary valve stenosis is not entirely clear; rare cases can be associated with genetic defects or inherited syndromes.
Physiologically, pulmonary valve stenosis creates a situation in which the right ventricle must squeeze more forcefully to pump blood past the narrowed valve. The burden on the right ventricle is directly related to the degree of narrowing. A more narrowed valve results in more stress being placed on the right ventricle. In cases of mild pulmonary valve stenosis, there is little if any significant hemodynamic burden placed on the heart.
Symptoms from pulmonary valve stenosis are actually quite uncommon. The majority of patients, even those with significant narrowing, rarely have any noticeable symptoms during infancy or childhood. Occasionally older children with long standing, severe pulmonary valve stenosis may develop fatigue with exercise.
Diagnosis of pulmonary valve stenosis can be made in a number of different ways. A patient with pulmonary valve stenosis usually comes to attention due to the presence of a heart murmur. This simply refers to the sound that blood is making as it flows past the narrowed valve. There are many other different causes of heart murmurs, including normal causes. An echocardiogram uses sound waves to visualize the intracardiac structures and is the easiest way to diagnoses the valve abnormality and the degree of narrowing.
There is a wide spectrum of treatment options for a patient with pulmonary valve stenosis. Most patients with mild pulmonary valve stenosis require no specific therapy whatsoever. In many cases the degree of narrowing spontaneously improves with time. Patients with mild pulmonary valve stenosis have a normal life-span and are free to participate in all activities without restriction in most cases.
Patients with severe or moderate to severe pulmonary valve stenosis require intervention to prevent long term damage to the heart. In the past, relief was accomplished through surgery; however, over the past 20 years balloon valvuloplasty through a cardiac catheterization has become the procedure of choice. A catheter (a long thin tube) is placed into the heart through a blood vessel in the leg. A balloon on the end of the catheter is then used to dilate the narrowed valve. In general, the success rate for this procedure is very good with an extremely low complication rate. Most patients requiring a valvuloplasty do well with no significant long-term limitations. Those patients who require surgery for whatever reason also tend to do very well long-term.
Up until recently, patients with any form of heart defect, including pulmonary valve stenosis, were recommended to use antibiotics prior to dental work or surgery to minimize the risk of heart-related infection. However, in May 2007 the American Heart Association changed this recommendation such that now most patients with congenital heart disease, including those with pulmonary valve stenosis, no longer require this precaution.