What Is Patent Ductal Arteriosus?
Patent ductal arteriosus, or PDA, is an opening between the two major blood vessels leading from the heart. It’s one of the most common heart problems in newborn babies.
The opening, called ductus arteriosus, is an important blood vessel in a baby. It connects the two major arteries that go from the heart. It's supposed to close soon after birth. A patent ductus arteriosus (“patent” means open) is one that doesn’t close.
In normal circulation, the right side of the baby’s heart pumps blood through the pulmonary arteries to their lungs. There, it picks up oxygen. The blood goes back to the left side of the heart, which pumps it through the aorta. From there, it goes to the rest of the body.
Babies don’t use their lungs before they’re born. They get oxygen from their mother’s blood. The ductus arteriosus is there to bypass the lungs. Instead, it sends blood straight from the pulmonary arteries to the aorta.
If it doesn’t close, blood can flow backward from the aorta to the pulmonary artery. That sends too much blood into the lungs and left side of the heart. Pressure builds in the blood vessels and heart chambers. Over time, that can cause fluid buildup in the lungs and an enlarged heart.
Patent Ductus Arteriosus Symptoms
Your baby may show no outward signs. But the doctor may notice that your baby’s heartbeat has a distinctive sound (called a murmur). If the opening is large, this condition affects how well your baby’s heart and lungs work. If it's serious, it can cause:
- Heavy, fast breathing or shortness of breath
- Trouble feeding and failure to gain weight
- A fast, pounding heartbeat
- Sweating when they’re active, as when feeding
Premature babies are more likely to have problems. They may not get enough oxygen, which leads to organ damage.
Patent Ductus Arteriosus Causes and Risk Factors
In the U.S., PDA is a fairly common heart defect. It happens in 8 out of every 1,000 premature births and 2 of every 1,000 full-term births.
Doctors don’t know what causes PDA, but they have found several risk factors in moms and babies:
- Premature birth. PDA happens more often in babies who are born too early than those who are full term.
- Family history and genes. If heart problems or conditions that affect your genes, like Down syndrome, run in your family, then your baby is more likely to have PDA.
- Rubella. The virus that causes this condition (also known as German measles) can pass from mom to baby during pregnancy and damage the baby’s blood vessels and organs, including their heart.
- Gender. PDA affects twice as many girls as boys.
Patent Ductal Arteriosus Diagnosis
If your baby has symptoms, their doctor may send you to a children’s heart specialist. This doctor is called a pediatric cardiologist. They’ll give your baby tests to see how well their heart works. An echocardiogram is the best tool to diagnose this issue. It makes pictures of the heart and blood vessels with sound waves. It will show the size of the PDA and how much blood is flowing through it.
Your child’s doctor could also recommend other tests like:
- Chest X-ray. This helps the doctor see the condition of your baby’s heart and lungs.
- Electrocardiogram (ECG or EKG). This test records the heart’s electrical activity.
- Cardiac catheterization. The doctor inserts a long, flexible tube, called a catheter, into a vein and guides it into the heart.
- Cardiac magnetic resonance imaging (MRI). This test takes pictures of your child’s heart using radio waves, magnets, and a computer.
Patent Ductal Arteriosus Treatment
Your child's doctor will close a PDA if the opening is large enough for blood to overload their lungs or to lower their chance of getting a heart infection. Doctors fix a PDA one of three ways:
Medicine. Nonsteroidal anti-inflammatory drugs (NSAIDs) can often close a PDA in a premature baby. They work to block a blood chemical that keeps it open. These drugs have side effects, so they may not be safe for all babies.
Catheter closure. Depending on their age, your child will get medication to either help them relax or sleep. Then, a surgeon will block the opening with a tiny metal coil or piece of mesh. They’ll put a thin tube called a catheter into a large blood vessel in your baby’s groin. Then they'll thread it through to their heart. The doctor will take a picture of the blood vessel (called an angiogram) to define its shape and size. The coil or mesh goes through the tube into the ductus arteriosus to stop the blood flow. For larger openings, the doctor could block the vessel with a plug-shaped device. Your child may go home the same day.
Surgical ligation. A surgeon can also tie or clamp the ductus arteriosus closed. They'll make a cut in the left side of the chest between the ribs to reach the area. Your baby will likely stay in the hospital at least a couple of days. Small PDAs often close on their own by the time your baby is a few months old, so they may not need surgery.
Doctors usually treat full-term babies or older children with the catheter procedure. Surgery may be best if the PDA is very large or your baby has other heart defects that need to be fixed.
For preemies, doctors usually try medicine first. If that doesn’t work, the doctor may suggest that you wait until your baby is big enough for a catheter procedure if they're OK otherwise.
Patent Ductal Arteriosus Complications
If left untreated, a large PDA can damage your baby’s heart and lungs and cause:
- High blood pressure in the lungs. Too much blood circulating through the PDA opening can lead to high blood pressure in the lungs, also called pulmonary hypertension. If it isn’t treated, this condition could be permanent.
- Heart failure. A PDA could cause a weak and enlarged heart and lead to heart failure, a condition that prevents the heart from pumping like it should.
- Heart infection (endocarditis). Your child may also be more likely to get an infection in the lining of their heart called endocarditis, but this is rare.
Patent Ductal Arteriosus Outlook
Treatments for this condition work well. If your baby doesn’t have other health problems, you can expect them to eat and grow normally soon after it’s closed. Your child probably won’t have any limits on physical activity as they get older. This is true whether doctors fix it or if it's so small you choose to leave it alone. Talk to your doctor about how often your child will need a checkup.