Patent Ductus Arteriosus (PDA) in Premature Infants
Arteries are blood vessels that carry blood away from the heart to the body. “Patent” means open. “Ductus arteriosus” means arterial canal. So the patent ductus arteriosus (PDA) is an opening between two arteries. The two arteries are the pulmonary artery and the aorta. The pulmonary artery goes from the heart to the lungs. The aorta is the main artery that carries blood from the heart to smaller arteries in the rest of the body. The PDA is a normal part of blood circulation while your baby is in your womb and doesn't breathe air. While the baby is still in the uterus, the PDA allows blood to flow from the pulmonary artery to the aorta, bypassing the lungs. Normally, the PDA closes within a few days after birth. However, in some babies, the PDA remains open, allowing oxygen-rich blood from the aorta to mix with oxygen-poor blood from the pulmonary artery. In the United States, this is a fairly common congenital (present at birth) heart defect. A PDA is more common in premature infants, but can be seen in full-term infants. It may also be associated with other congenital heart defects. It is more common in girls.
When is the PDA a problem?
A PDA that remains open beyond a few days after birth can strain the heart and increase the blood pressure in the lungs. This can causes pulmonary congestion (fluid buildup in the lungs) and may make it hard for the baby to breathe. The heart also has to work harder.
How is PDA diagnosed?
The problem can be detected with an echocardiogram (ultrasound imaging test of the baby’s heart). In mild cases, there may be no symptoms. Or symptoms can include:
A heart murmur
Pulses that are stronger than normal in the upper part of the body and diminished or absent in the legs
Low oxygen levels in the legs and lower body
Signs of heart failure, such as sweating during feeding
How is PDA treated?
The ductus may close on its own, without treatment. If it doesn’t, treatments include:
Medication. Certain medications can constrict the artery, shrinking the duct and allowing it to close. The medication is given by IV over a period of a few days. During this time, the baby is monitored closely.
Catheter Based Procedure. This may be done on a small PDA if the treatment with medication did not work. Children must be large enough to qualify for the procedure. Through a catheter (long thin tube) in the leg, a small metal coil, or other device is advanced to the PDA and placed like a plug to block blood flow between the two vessels.
Surgery. This may be performed if your baby can’t tolerate the medication, or if treatment with medication has not worked. Typically it is reserved for children who are too small for a catheter-based procedure, or if a catheter-based procedure was not successful. The surgeon may advise surgery if there is planned treatment for other related congenital heart defects. The surgeon makes an incision between the ribs on the left side of the chest and clamps or ties off the opening in the blood vessel. The surgery doesn’t involve the heart muscle. This surgery has a high success rate and a low risk of complications.
What are the long-term effects?
Once the ductus is closed, there are rarely long-term complications.