Patent Ductus Arteriosus

What is patent ductus arteriosus?

Patent ductus arteriosus (PDA) is a birth defect in the blood vessels leading from the heart. It happens when a channel between 2 major blood vessels before birth fails to close the way it is supposed to shortly after birth.

How does it occur?

Every baby is born with an open connection between the 2 major blood vessels leading from the heart: the pulmonary artery and the aorta. This channel between the 2 blood vessels is needed while the baby grows in the womb. It is called the ductus arteriosus.

The baby does not need the channel after birth and normally it closes soon after birth. When it does not close it is called a patent ductus arteriosus, or PDA. This problem is quite common in premature infants, especially if their lungs are not mature, but it is rare in full-term babies. When it happens, the problem is usually discovered soon after birth. In some cases it may not be found until later in life.

When the channel stays open, some of the blood that should have gone to the rest of the body through the aorta goes back to the lungs through the pulmonary artery instead.

Doctors are not sure what causes this birth defect.

What are the symptoms?

Babies who have a small open channel often have no symptoms, but a heart murmur can be heard with a stethoscope. (A heart murmur is an extra sound made between heartbeats. These murmurs are caused by the blood leaving the heart through the narrowed lung artery.)

If the PDA is large, a baby may not gain weight easily. The baby may become short of breath and sweat when crying or playing. An older child with PDA may not be able to exercise as much as normal and may have lung infections often.

How is it diagnosed?

The healthcare provider will use a stethoscope to listen for a heart murmur. However, some PDAs do not cause a heart murmur.

An echocardiogram, a special test that uses sound waves to create a picture of the heart, can be used to look for a PDA.

A chest X-ray of a child with a PDA will often show an unusual amount of blood in the lungs.

How is it treated?

A PDA in a full-term baby normally closes within 3 days. In a premature baby it often closes by itself within weeks or months and does not need treatment.

A medicine called indomethacin is often used to close the PDA in premature babies. However, if the PDA is large or the baby is older, medicine may not be an option for treatment.

Full-term babies or premature babies whose PDA does not close usually need surgery. There are 3 common ways to close a PDA:

• The surgeon makes a small cut under the armpit. The ribs are spread (not broken) so the surgeon can then tie off the PDA.
• Using a type of surgery called thoracoscopic surgery, 2 or 3 small tubes are inserted in the baby's side. Small instruments are used to tie off the PDA through these small tubes.
• Using a procedure called cardiac catheterization, a very thin tube is inserted in a leg artery and pushed through the artery to the PDA. Special coils or other devices are then inserted into the PDA to keep blood from flowing through it.

How long do the effects last?

Surgery involves little risk, corrects the problem, and enables a child to grow and develop normally.

In some cases a child may need to take antibiotics before dental work and some other procedures to prevent infection of the heart.