Pulmonary stenosis is a congenital heart disorder where blood flow is blocked between the right ventricle and pulmonary artery. This blockage is in the valve (pulmonary valve) that separates the right ventricle and the arteries that deliver blood with low oxygen to the lungs.
The Problem
In a healthy heart, the right atrium receives (oxygen depleted) blood from the body and then passes it to the right ventricle. Form the right ventricle then passes it to the pulmonary artery, which carries blood into the lungs. The blood becomes oxygenated in the lungs and then it re-circulates and delivers oxygen to the body by the pumping mechanism of the left ventricle. The pulmonary valve is the valve between the right ventricle and the pulmonary artery. If this valve is obstructed, blood cannot properly flow to the lungs.
Usually, the problem is with the leaflets in the valve. In a healthy valve, three flexible leaflets move aside easily to enable the blood to pass through. In a defective valve, the leaflets may be molded together or stiffened, so they are not as pliable as usual. As a result, he narrowing of the valve obstructs blood flow.
Since PVS prevents enough blood from flowing in to the lungs, the right ventricle has to work harder to compensate for the obstruction. This cause an increase of pressure to the right ventricle and the right ventricle muscle compensate by becoming enlarged, a condition known as hypertrophic cardiomyopathy. This shouldn’t present a problem in itself, but reflects the obstructive defect on the pulmonary valve. PVS can also cause blood to pass straight from the right atrium to the left atrium, which leads to a condition called cyanosis. PVS does not usually cause heart failure (a defect of the right ventricle to maintain the pumping ability due to increase of pressure)
Symptoms
Dyspnea (shortness of breath) and fatigue are the most frequent symptoms, but patients may remain asymptomatic for long periods as long as the right ventricle maintains a normal pumping capability via compensatory mechanisms (hypertrophy). This disorder occasionally may occur in an acquired form with hypertrophic cardiomyopathy (a bulging of the septum into the right ventricle outflow tract) or perhaps secondary to a pericardial tumor. On physical examination, the physician is able to oscultate (listen) and identifies this disorder as a heart murmur. This murmur is present at birth since this disorder is usually congenital.
PVS is diagnosed with echocardiography and electrocardiography. Occasionally cardiac catherization might be necessary.
In severe cases, when the infant is exhibiting cyanosis (a blue coloring due to low oxygenation) during the first few days of his or her/his life, immediate surgery is necessary to open or reconstruct the valve. The less invasive option is a highly successful procedure called balloon dilation. A balloon tipped plastic tube is inserted through a vein in the leg and threaded to the heart. This is only a possibility when the valve is of normal size and simply needs to be opened. If the valve is malformed, more invasive surgery may be necessary. For some infants who undergo surgery during those first days, the surgery may have to be repeated in a few years.
Children who have mild PVS usually don’t require surgery.
