Patent Ductus Arteriosus (PDA)
Patent ductus arteriosus (PDA) is a congenital heart defect that is common in babies born prematurely, but rare when pregnancies go full-term. The ductus arteriosus is a temporary blood vessel that, in fetuses, allows the blood to skip circulation to the lungs, because oxygen is delivered through the mother’s placenta. (The word “patent” means “open” in Latin.)
Once a baby is born and begins breathing through its own lungs, the ductus arteriosus begins to narrow and is meant to close within a few days. If this doesn’t happen, the baby has PDA, a condition that may require intervention.
“PDA leaves a hole that might be three to five millimeters in diameter—so pretty small, but in a small baby that can be a big problem,” says interventional cardiologist Jeremy Asnes, MD, chief of pediatric cardiology for Yale Medicine and co-director of the Yale New Haven Children’s Hospital Heart Center.
The traditional treatment for a PDA that doesn’t close naturally is heart surgery. Though the procedure is life-saving, it can be traumatic for a small body. Catheterization techniques to close a PDA were developed in 1990s and are now the standard of care in children. However, only recently have techniques and devices been developed to address this problem in small, prematurely born babies.
What is the ductus ateriosus?
In a fetus, the ductus arteriosus allows blood to be pumped directly from the heart to the aorta, the main artery of the body, without going through the lungs. This is necessary for the proper development of circulation. “If a baby is born prematurely, then the signals for the ductus arteriosus to close often don't work very well, and the ductus might stay open. It then becomes a burden on the circulation, as opposed to supporting circulation,” Dr. Asnes says.
Some small PDAs may cause no symptoms at all and will close on their own before the child is a year old. Larger PDAs can cause extra blood to flow into the lungs, which can increase pressure in the lung arteries, putting a strain on the heart, and even cause heart failure. If this happens, a baby may need mechanical ventilation for a long period of time. This makes feeding difficult and also raises risk of abnormal neurodevelopment.
In rare cases, PDAs aren’t diagnosed until adulthood. Over time, the additional blood flow to the lungs can put adults at risk for such serious problems as pulmonary hypertension and heart rhythm abnormalities.
Are some babies at higher risk for PDAs?
Premature babies are at higher risk for PDAs, as are babies with genetic conditions such as Down syndrome, those with neonatal respiratory distress syndrome, and babies born to mothers who had rubella during pregnancy. It’s twice as common in girls than it is in boys.
What are the symptoms of PDA?
Babies who have a PDA may have some combination of the following symptoms:
- Heart murmur
- Especially strong pulse
- Rapid breathing
- Failure to thrive
- Poor feeding
- Poor growth
- Sweating during feeding
- Shortness of breath
- Increase in heart rate
How is a PDA diagnosed?
If a doctor suspects an infant’s symptoms may be caused by a PDA, an investigative X-ray may be done to see whether the heart is enlarged and to look for abnormal blood flow to the lungs. An echocardiogram (an ultrasound of the heart) confirms the diagnosis of PDA. Other tests may be done as well.
What are the treatments for a PDA?
In many cases a PDA will resolve on its own in the first few months or at least within the first year of life. Medication may be prescribed to help the ductus close. If medication isn’t effective or a baby’s health is endangered, catheterization or a surgical procedure may be required to close the PDA.
- Surgery: Using a traditional surgical approach, the surgeon makes an incision between the ribs on the left side of the baby’s chest, using either sutures or a clip to close the ductus. This approach may be necessary in babies who are especially small, or who have other congenital heart defects that require treatment.
- Catheterization: This minimally invasive approach involves only a small needle puncture in the leg. The cardiologist inserts a catheter (a thin plastic tube) into the large vein, threading it up to the heart. The hole is then closed with a “corck” (typically made out of materials such as metal and extra thin GORE-TEX fabric). “There are no stitches or sutures and no scarring,” Dr. Asnes says. The doctors use X-ray cameras to track their progress.
A team of doctors usually determines the best approach to fixing the PDA. Catheterizations can usually be performed in the first weeks of life. “For prematurely born babies, we like to get these [catheterization] procedures done somewhere between two and four weeks of age,” Dr. Asnes says. After a PDA procedure, a baby recovers in the neonatal intensive care unit.
Some cardiologists would like to make catheterization the standard of care for as many young heart patients with PDA as possible.
“In a very small infant, surgery can often make the baby sicker as an initial response to the operation. While the catherization procedure is not without trauma, it's a completely different realm,” says Dr. Asnes, adding that far fewer reports of setbacks and complications arise after catheterization than surgery in small babies. “The babies we've treated with catheterization have all sort of not noticed the procedure, which is wonderful. The neonatologists tell us there really is no change, other than a gradual improvement once the ductus is closed.”
Some patients with PDAs have other heart defects as well; catheterization can be better for those who will require multiple surgeries in the first few years of life, Dr. Asnes says. “Sometimes, if we can perform the first as a catheter-based procedure, it makes a second procedure much, much easier. Because now surgeons are starting off with a heart that has not been operated on,” he says.
What is the outlook for a baby born with PDA?
The vast majority of children who are treated for PDAs live a normal life. While they should be monitored for complications—especially if they have other disorders as well—long-term problems are rare, and in most cases, no follow-up treatment is necessary.
How is Yale Medicine unique in the treatments of PDAs?
Yale Medicine pediatric cardiologists at Yale New Haven Children’s Hospital Heart Center were early adopters of catheterization for pediatric patients, and the first in Connecticut to use the approach to treat PDA in prematurely born newborns, according to Dr. Asnes.
Yale Medicine Pediatric Cardiology has a long history of innovation in the fields of both congenital and acquired heart disease, and has been going through a stage of growth and expansion. We provide the complete spectrum of cardiovascular care to patients from our community, the state, and Northeast region.