Patent ductus arteriosus, or PDA, is a heart defect that can develop soon after birth. It affects the way blood flows through a baby’s lungs. Mild PDA might not need treatment, but some children with the defect may require catheterization or surgery.

Pediatric cardiologist John Thomson of the Blalock-Taussig-Thomas Pediatric and Congenital Heart Center describes what you should know additionally about PDA.

What is patent ductus arteriosus?

PDA occurs when the opening between the aorta (the artery that carries oxygen-rich blood to the body) and the pulmonary artery (the artery that carries oxygen-poor blood to the lungs) does not close as it should.

How does patent ductus arteriosus affect blood flow?

PDA causes too much blood to flow into babies’ lungs. While a baby develops in the womb, an opening between the aorta and pulmonary artery (the ductus arteriosus) allows blood to bypass the baby’s lungs and go straight to the body. Blood does not need to go to the lungs first, because the mother supplies the baby with oxygenated blood through the placenta. The ductus arteriosus should close on its own within a few days after birth. When the opening does not close, this connection between arteries is considered a patent, or open, ductus arteriosus. Small connections may not cause problems, but larger connections can cause a range of symptoms and require closure.

Patent Ductus Arteriosus Causes

Experts aren’t sure exactly what causes PDA. It is much more common in premature infants (babies born more than three weeks before the projected due date). Studies suggest PDA affects about 65% of infants born before the 28th week of pregnancy. It is rare in full-term babies and is twice as common in girls than in boys.

Sometimes PDA occurs with other heart defects. The risk of congenital heart defects like PDA may also increase due to:

• Certain genetic conditions
• Family history of congenital heart conditions
• Fetal distress in the womb
• Infections in the mother or fetus during pregnancy, such as rubella
• Other pregnancy-related risk factors, such as smoking or taking certain medications

Patent Ductus Arteriosus Symptoms

Symptoms of PDA depend on the size of the opening between a baby’s aorta and pulmonary artery. If the opening is small, your baby may not have symptoms. But a larger opening may cause symptoms such as:

• Fast or hard breathing
• Frequent respiratory infections
• Heart murmur (a “whooshing” sound made by abnormal blood flow through the heart)
• Poor weight gain
• Trouble feeding or tiredness while feeding

Patent Ductus Arteriosus Diagnosis

A health care provider may notice the signs of PDA soon after birth. During a physical exam, they listen for a heart murmur or congestion in the lungs. They also check the baby’s pulse rate and blood pressure.

Other tests for PDA help identify signs of the hole and may include:

• Echocardiogram — an ultrasound scan of the heart
• Electrocardiogram — a test that uses electrodes to evaluate the heart

Patent Ductus Arteriosus Treatment

If a small PDA does not cause severe symptoms, it may not need treatment. Sometimes the connection may close on its own a few months after birth. A baby may need medicine such as indomethacin (an anti-inflammatory) during these months to help close the connection, or water medicine (diuretics) to reduce the risk of fluid buildup. Larger connections usually need treatment with catheterization or surgery.

Cardiac catheterization

Catheterization is the most common treatment for PDA. During this minimally invasive procedure, a pediatric interventional cardiologist:

• Makes a tiny incision near a large blood vessel in the leg
• Inserts a catheter (thin, flexible tube) into the blood vessel and threads it up to the PDA
• Slides a coil or other plug-like device through the catheter and into the PDA to close it

Patent ductus arteriosus surgery

Patent ductus arteriosus surgery is usually reserved for babies with very large PDAs. Open surgery presents more risks than cardiac catheterization and requires a longer recovery time. During this procedure, a pediatric heart surgeon:

• Makes an incision in the chest
• Closes the connection with stitches or small metal clips

What are the complications of patent ductus arteriosus?

Left untreated, PDA may cause complications such as:

• Heart failure
• Endocarditis (inflammation and infection of the lining of the heart)
• Pulmonary edema (fluid in the lungs)
• Pulmonary hypertension (high blood pressure in the blood vessels of the lungs)

Living with patent ductus arteriosus

The outlook for children who receive PDA treatment and have no other heart conditions is excellent. Most children go on to lead full, healthy lives with no restrictions on activities. They may need periodic checkups with their pediatric cardiologist to make sure no other heart or lung problems have developed.

People who had PDA treatment as an infant or child should seek care from an adult congenital heart specialist as they transition into adulthood. In very rare cases, a second surgery may be necessary if the hole opens up again.