Some babies develop a condition called patent ductus arteriosus (PDA) soon after birth. It occurs when a blood vessel that is critical to blood circulation before birth but not necessary after birth does not close as it should. Before birth, the blood vessel, called the ductus arteriosus, connects the two major arteries from the heart: the pulmonary artery (which carries blood from the heart to the lungs) and the aorta (which carries blood from the heart to the body). Before birth, the PDA diverts oxygen-containing blood from the placenta away from the baby's lungs (which are naturally collapsed), and carries it to the aorta to be distributed to the baby's body.

When the baby is born and begins to breathe, the lungs (no longer collapsed) provide oxygen to the blood instead of the placenta. The ductus arteriosus is supposed to close by itself within a few days of birth. But, in some babies, it stays open (patent means open). When the PDA remains open, blood is able to flow directly from the aorta into the pulmonary artery, which delivers blood to the lungs. This flow is in the opposite direction from when the baby was in the womb. This causes extra blood flow to go to the lungs, placing strain on the heart and increasing the blood pressure in the lung arteries.

PDA affects about 3,000 infants each year in the United States, according to the National Heart, Lung and Blood Institute. The sixth most common heart defect, PDA is more common in premature (born too early) babies, but it also occurs in full-term infants. PDA is twice as common in girls as boys. The risk of PDA is increased at higher altitudes due to oxygen concentrations that are lower than at sea level.

Symptoms

PDA may be mild with no symptoms or ill effects. Or it may be serious, with symptoms that include difficulty breathing, shortness of breath, poor weight gain and other symptoms of congestive heart failure (CHF).

Progression and Possible Complications

If a moderate or large PDA is not treated, extra strain is placed on the heart and lung vessels. Irreversible damage to the blood vessels of the lungs can occur. If untreated, this damage can lead to death, typically in the fourth or fifth decade of life. Infection of the blood vessels may also occur. This condition, called bacterial endocarditis, may be life threatening.

Treatments

In some babies born with PDA and with an otherwise normal heart, the blood vessel shrinks and closes on its own. In others, the PDA may need to be closed. Three options are available for closing the PDA: medications, a catheterization procedure and surgery.

Medications 

When PDA causes congestive heart failure in the neonatal period (the first month after birth), medications such as indomethacin or ibuprofen may be given by intravenously (through the veins). This is more likely in premature infants. These medications work best in premature babies and typically do not work outside the neonatal period.

In infants born with certain other heart defects, doctors may actually want to keep the ductus arteriosus open to maintain blood flow to the body or lungs until surgery can be performed to repair the defective heart structures. Medication (prostaglandin E1) may be given to keep the blood vessel open.

Catheterization to Close the PDA

Doctors may recommend closing a PDA using a procedure performed in the hospital’s catheterization lab, or “cath lab.” In this procedure, a small thin tube (catheter) is inserted into a blood vessel at the top of the leg and threaded through the arteries to the ductus arteriosus. The doctor then delivers a small “occluding” (closure) device through the catheter to the point at which the PDA is connected to the pulmonary artery. There, the doctor implants the device to close the ductus arteriosus. 

Surgery

When neither medications nor catheterization closure are helpful in treating PDA, surgical closure may be chosen. The procedure is performed through a surgical incision (thoracotomy) in the side of the chest while the heart continues to beat.