Peripheral Pulmonary Stenosis (PPS)
Newborns have relatively small blood vessels to the lungs (pulmonary arteries). After the child is born, there is a huge increase in blood flow from the main pulmonary artery to the relatively smaller branches. Turbulence arises at the fork where the main pulmonary artery splits into two, with one side going to each lung. The turbulence appears as the blood crosses the relatively small blood vessels. The heart murmur of peripheral pulmonary stenosis (PPS) may be heard with a stethoscope. Because PPS is caused by turbulence at the small-vessels, it is more common in smaller babies (under 7 pounds). Over time, anywhere between two to six months, these vessels will grow larger. By that time, the turbulence will stop and the murmur will fade away. This condition is called physiologic PPS, as there is no permanent narrowing or obstruction in the pulmonary arteries.
Rarely, we may see patients with diffuse narrowing of the pulmonary vessels. This type of PPS is very rare but may be seen in patients with Tetralogy of Fallot, William’s syndrome and Noonan syndrome. This particular type of PPS may require enlargement of the narrowed pulmonary arteries by means of angioplasty, stent, or surgery.
Patients with the most common variety of PPS, the physiologic type, would not require any type of treatment. These patients may be followed for a limited time only to make absolutely certain that the murmur was not something else more serious.