What is Patent Ductus Arteriosus?
Patent ductus arteriosus (PDA) is a fairly common congenital heart defect that is seen in about 3,000 newborns every year in the U.S. (Cleveland Clinic). It occurs when a temporary blood vessel, called the ductus arteriosus, does not close soon after birth. Symptoms may be minimal or severe. In rare cases, the defect can go undetected and can exist in adulthood. Correction of the defect is usually successful and restores the heart to its normal function
The Ductus Arteriosus
In a normally functioning heart, the pulmonary artery carries blood to the lungs to collect oxygen. The oxygenated blood is then pumped through the aorta (the body’s main artery) to the rest of the body. In the womb, the aorta and pulmonary artery are connected by a blood vessel called the ductus arteriosus. It allows blood to flow from the pulmonary artery to the aorta and out to the body without going through the lungs. This occurs because the developing child gets oxygenated blood from the mother, not from its lungs.
Soon after a baby is born, the ductus arteriosus should close up to prevent mixing oxygen-poor blood from the pulmonary artery with oxygen-rich blood from the aorta. When this closing up does not happen, the baby has the defect called patent ductus arteriosus (PDA). If the defect is never detected, the baby may grow into an adult with PDA, although this is rare.
What Causes Patent Ductus Arteriosus?
PDA is a fairly common congenital heart defect in the United States, however doctors are not sure exactly what causes the condition. Premature birth can put babies at risk—PDA affects eight in 1,000 premature births, versus two out of every 1,000 full-term births. PDA is twice as common in girls as it is in boys (NHLBI).
Symptoms of Patent Ductus Arteriosus
The opening in the ductus arteriosus can range from small to large, which means that symptoms may be very mild to severe. If the opening is very small, there may be no symptoms and your doctor may only find the condition by hearing a heart murmur.
Most commonly, an infant or child with PDA will have the following symptoms:
- rapid and heavy breathing
- poor weight gain
- little interest in feeding
In the rare case that PDA goes undetected, an adult with the defect may experience symptoms that include heart palpitations, shortness of breath and complications such as high blood pressure in the lungs, an enlarged heart, or congestive heart failure.
How Is Patent Ductus Arteriosus Diagnosed?
For infants, a doctor will usually diagnose PDA after listening to your child’s heart. Most PDA causes a heart murmur (an extra or unusual sound in the heartbeat), which a doctor can hear through a stethoscope. A chest X-ray may also be performed in order to see the condition of a baby’s heart and lungs.
Premature babies may not have the same symptoms as full-term births, and may require additional tests to confirm PDA.
An echocardiogram (echo) is a test that uses sound waves to create a picture of the baby’s heart. It is painless and allows the doctor to see the size of the heart, and also if there is any abnormality in blood flow. Echo is the most common way PDA is diagnosed (Boston Children’s Hospital).
An EKG records the electrical activity of the heart and is used to detect irregular heart rhythms. In babies, this test can also show whether the heart is enlarged.
Complications of Patent Ductus Arteriosus
Most cases of PDA are diagnosed and treated soon after birth, and it is very unusual for PDA to go undetected into adulthood. If it does, however, it can cause several health problems. The larger the opening is, the worse the complications. However rare, untreated adult PDA can lead to other medical conditions in adults such as:
- shortness of breath or heart palpitations
- pulmonary hypertension, or raised blood pressure in the lungs, which can damage the lungs
- endocarditis, or inflammation of the lining of the heart due to a bacterial infection; people with structural heart defects are at a higher risk of infection than others
In very serious cases of untreated adult PDA, extra blood flow can eventually increase the size of the heart, weakening the muscle and its ability to pump blood effectively. This can lead to congestive heart failure and death.
Treatment Options for Patent Ductus Arteriosus
In cases where the opening of the ductus arteriosus is very small, no treatment may be necessary as the opening can close as an infant gets older. In this case, your doctor will want to monitor the PDA as the baby grows. If it does not close on its own, medication or surgical treatment will be required to avoid complications.
In a premature baby, a drug called indomethacin (a medication similar to ibuprofen) can help to close the opening in PDA. When given intravenously, this medication can help to constrict muscles and close off the ductus areteriosus. This type of treatment is typically only effective in newborns. In older infants and children, further treatment may be necessary.
If the opening is large, or it does not seal off on its own, surgery may be necessary to correct the defect. This type of treatment is typically only for children who are six months or older; however, surgical closing of the ductus arteriosus can be done in younger infants if symptoms are severe. For surgical procedures, your doctor may prescribe antibiotics to prevent bacterial infection after leaving the hospital.
As long as PDA is detected and treated, the outlook is very good. Recovery for premature babies will depend on how early the baby was born and whether or not other illnesses are present. Most infants will make a complete recovery without experiencing any PDA-related complications.