The word "atresia" means "no opening."
The word “atresia” means “no opening.” With pulmonary atresia, the valve that lets blood flow from the lower-right chamber (the right ventricle) to the lungs has not formed or is closed.
Instead of following the normal route through the lungs, oxygen-poor blood travels directly from the upper-right chamber (the right atrium) to the left side of the heart. This oxygen-poor blood is then pumped back into the body. The lack of oxygen-rich blood makes the fingers, toes, and lips appear blue, a condition called cyanosis.
Babies with pulmonary atresia seem normal before birth. This is because a passageway called the ductus arteriosus connects the pulmonary artery to the aorta in the fetal heart. The ductus arteriosus begins to close naturally after birth. In normal babies, a new valve opens that lets blood flow from the right ventricle to the lungs. But in infants with pulmonary atresia, the valve does not open. This means that the only path for blood to reach the lungs will soon begin to close.
How is it treated?
Newborns with pulmonary atresia are usually given a medicine called prostaglandin E1 to keep the ductus arteriosus open after birth.
The type of surgery recommended depends on the size of the right ventricle and the pulmonary artery. If they are normal in size and the right ventricle is able to pump blood, open heart surgery can be done to make blood flow through the heart in a normal pattern.
If the right ventricle is small and unable to act as a pump, doctors may perform an operation called the Fontan procedure. In this procedure, the right atrium is connected directly to the pulmonary artery.
In some cases, if the right ventricle and pulmonary artery are too small, it may be impossible to repair the defect.