Patent Ductus Arteriosus

Overview

Some babies develop a condition called patent ductus arteriosus (PDA) soon after birth. It occurs when a blood vessel that's critical to blood circulation before birth, but not necessary after birth, doesn’t 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, which causes extra blood flow to go to the lungs, places a strain on the heart, and increases the blood pressure in the lung arteries.

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.

Progression and possible complications

If a moderate or large PDA is not treated, extra strain is placed on the heart and lung vessels, which may result in irreversible damage to the blood vessels of the lungs. If untreated, this damage can lead to death, typically in the fourth or fifth decade of life. A potentially life-threatening infection of the blood vessels, bacterial endocarditis, may also occur.

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, acetaminophen, or ibuprofen may be given intravenously (through the veins). This is more likely in premature infants. These medications work best in premature babies and typically don’t 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. 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. The doctor then 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 in the side of the chest (thoracotomy) while the heart continues to beat.