What is patent ductus arteriosus?

Blood tests can identify infants with patent ductus arteriosus, a type of heart disease that is a common condition in premature infants. Patent ductus arteriosus is a persistent, abnormal opening between two major blood vessels leading from the heart.

Before birth, the blood vessel called the ductus arteriosus connects the two major arteries from the heart. One is the pulmonary artery, which carries blood from the heart to the lungs, and the second is the aorta, which carries blood from the heart to the body. As the baby develops, the ductus arteriosus diverts blood away from the lungs, which are collapsed when the baby is inside the mother’s womb. The ductus arteriosus carries the blood to the aorta to be distributed to the body. When the baby is born and begins to breathe, the ductus arteriosus is supposed to close within a few days. But in some babies, it stays open and this is called a persistent patent ductus arteriosus (PDA).  This allows blood to flow directly from the aorta into the pulmonary artery. As a result, there is too much blood flowing toward the lungs, placing strain on the heart and increasing the blood pressure in the lung arteries.

The ductus arteriosus is a blood vessel in a fetus that connects the pulmonary artery, which carries blood to the lungs, and the aorta, which carries blood to the body, so that blood flow bypasses the lungs. Normally, this blood vessel closes at birth as the baby starts breathing. If the vessel does not close, it is known as a patent (open) ductus arteriosus (PDA).

A patent ductus arteriosus allows some oxygen-rich blood to flow from the aorta back into the pulmonary artery and to the lungs instead of to the rest of the body. Because some of the blood intended for the body returns to the lungs, the left side of the heart has to pump harder to get enough blood to the body. This can enlarge and weaken the heart.

Some babies do not have symptoms from a patent ductus arteriosus.  But this abnormality often causes symptoms, such as poor feeding and shortness of breath. An older child may develop heart failure or an infection of the heart's inner lining (infective endocarditis). How bad the symptoms get and whether complications develop depend on how much blood flows through the ductus.

Treatment for a patent ductus arteriosus might be medicine that helps close the blood vessel. Or a doctor will insert a small closure device into the heart during a heart catheterization. This prevents blood from flowing into the lungs. If a heart catheterization can't be done, a surgeon might operate to close the PDA.