Patent Ductus Arteriosus

Signs and Symptoms

The patent ductus arteriosus is a temporary blood vessel that is part of the fetal blood circulation system, and it usually closes shortly after birth. If it fails to close as it should after birth, already oxygenated blood may leak back into the lungs. This condition strains the heart and can cause vascular disease and heart infections.

While a baby is in the womb, the patent ductus arteriosus is open and connects two arteries -- the pulmonary artery and the aorta:

• Pulmonary artery -- This artery sends blood 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.

When the patent ductus arteriosus is open, it diverts blood from the pulmonary artery to the aorta, bypassing the lungs and the heart. While in the womb, there's no need for blood to flow to the lungs for oxygen since babies rely on oxygenated blood from their mothers. Babies don't breathe through the lungs until after birth.

After a baby is born and his or her lungs are functioning, blood is pumped from the right side of the heart up through the pulmonary artery to the lungs, where the blood is filled with oxygen. From the lungs, the blood travels back down to the left side of the heart, where the newly oxygenated blood is pumped to the aorta and the rest of the body.

The patent ductus vessel usually closes within the first 15 hours of life. Almost all close during the first year. If the ductus stays open after birth, it is called a patent ductus, and blood may leak back into the lungs because of the higher pressure in the aorta.

This condition may occur in children with otherwise normal hearts but also may occur in conjunction with other heart defects. In some conditions, the open ductus may compensate for blockage elsewhere in the heart's circulation system. On occasion, doctors may prescribe medication to keep the ductus open.

Most children with PDA don't have obvious symptoms unless congestive heart failure develops. PDA symptoms associated with congestive heart failure include rapid breathing, feeding difficulties and cold sweat.

If the ductus doesn't close, it allows oxygenated blood to flow back into the lungs instead of out to the rest of the body through the pulmonary artery. If the vessel is small, this isn't a serious problem, but a large ductus results in too much blood flowing through the lungs and puts a strain on the heart, which can lead to congestive heart failure. It also can cause the pulmonary arteries to thicken into a condition called pulmonary vascular disease. Children with PDA also are at increased risk for heart infections called endocarditis.

Diagnosis

Your doctor may hear a distinctive heart murmur that may lead him or her to suspect PDA. Further tests may include:

• Chest X-ray
• Electrocardiogram (ECG or EKG)
• Echocardiogram

Treatment

A small PDA may be treated with anti-infection medication since the vessel often will close on its own. Different medications will be prescribed if congestive heart failure develops. In newborns, a drug called Indomethacin may be prescribed to close the ductus.

If the PDA is still open after the child is 1 or 2 years old or if the congestive heart failure isn't responding to medication, the opening will be closed either through open surgery or a less invasive catheter procedure.

• Catheter Procedure -- Thin, flexible, plastic tubes called catheters are inserted into the large blood vessels in the legs through a tiny incision. Modern imaging technology allows the doctor to see where he or she is guiding the catheter. In the heart, the catheters are used as conduits to place small metal coils in the ductus vessel. The coils block blood flow through the ductus. This procedure is usually done without an overnight hospital stay.

• Surgery -- Surgical treatment may be necessary if the PDA is large or the baby is small. A small incision is made on the left side between the ribs. The ductus is either tied off or divided. The surgery usually requires a hospital stay of several days for recovery.