Pulmonary Atresia

Signs and Symptoms

Pulmonary atresia occurs when the pulmonary valve has not formed. Without this valve, blood can't flow to the lungs to become oxygenated. This isn't a problem before birth because the fetus relies on oxygenated blood from the mother to live.

The heart consists of four chambers: the two upper chambers, called atria, where blood enters the heart, and the two lower chambers, called ventricles, where blood is pumped out of the heart. The flow between the chambers is controlled by a set of valves that act as one-way doors.

Normally blood is pumped from the right side of the heart through the pulmonary valve and the pulmonary artery to the lungs, where the blood is filled with oxygen. From the lungs, the blood travels back down to the left atrium and left ventricle. The newly oxygenated blood then is pumped through another big blood vessel called the aorta to the rest of the body.

While a baby is in the womb, a blood vessel called the patent ductus arteriosus (PDA) is open and connects two arteries -- the pulmonary artery and the aorta:

• Pulmonary artery -- This artery sends blood from the right side of the heart up to the lungs. From the lungs, the oxygenated blood is pumped back into the heart and then to the aorta.
• Aorta -- This artery distributes oxygenated blood from the left side of the heart to the rest of the body.

In pulmonary atresia, because there is no way for blood to leave the right ventricle, blood that enters the right atrium passes across an opening into the left side of the heart which pumps it into the aorta. The only way that blood can reach the lungs is through the PDA.

A baby with an undeveloped pulmonary valve often has a small right ventricle, the chamber on the right side of the heart from which blood usually enters the lungs via the pulmonary valve and pulmonary arteries. Babies with pulmonary atresia have reduced oxygen in their blood, a condition called hypoxia. The baby also may turn blue (cyanotic) so pulmonary atresia may also be called "blue baby syndrome."

Other symptoms include:

• Difficult or rapid breathing
• Lethargy
• Cool sweat

Diagnosis

Blueness is always a sign of a problem. Your baby's doctor may notice a heart murmur, an extra noise that occurs during the heartbeat. Tests used to diagnose pulmonary atresia include:

• Chest X-ray
• Electrocardiogram (ECG or EKG)
• Echocardiogram
• Catheter procedures to determine pressure and oxygen in the heart

Treatment

Initial treatment is an intravenous drug called prostaglandin E-1 to keep the patent ductus arteriosus from closing and allow blood to flow between the pulmonary artery and aorta, thereby bypassing the valve and heart. But this only works temporarily. Your child also may be placed on a ventilator or oxygen to improve respiration.

Immediate surgery usually is necessary to increase blood flow to the lungs. Surgeons create a passageway by inserting a tiny piece of tubing called a shunt between the pulmonary artery and the aorta to increase flow to the lungs. Later, after the first year of life when the baby's lungs have developed more, a second operation called a Fontan procedure may be performed. It connects the right atrium, where deoxygenated blood collects from the body, directly to the pulmonary artery by creating a channel through or just outside the heart to bypass the undeveloped pulmonary valve.

Long-term treatment may include drugs to control heart rhythm disturbances and antibiotics may be needed to prevent infection during other surgery or dental procedures.