The baby in the womb primarily exchanges oxygen through the placenta from the mother. A small amount passes through the lungs, so a patent ductus arteriosus (PDA) is necessary to send most of the blood from the placenta to nourish the body. After birth, under normal conditions, this ductus arteriosus will contract and close automatically. However, in some cases such as premature birth, oxygen deprivation, acidosis, or high pulmonary pressure, the body’s mechanism fails, resulting in a patent ductus arteriosus.
Patent ductus arteriosus is found in up to 4 per 1,000 live births, accounting for 10% of all congenital heart disease cases, and is found in as high as 65% of very low birth weight premature infants.
If the patent ductus arteriosus is large, it can cause pulmonary edema in the child, requiring increased respiratory support. Some cases may develop intestinal infections or may be severe enough to cause pulmonary hemorrhage and death.
If the patent ductus arteriosus is small, it may not show symptoms in the newborn period. It is often diagnosed by physical examination hearing a heart murmur or slower weight gain compared to peers. Currently, closure of the patent ductus arteriosus is recommended in all cases, even if asymptomatic,
to prevent infective endarteritis.
Methods of closing the patent ductus arteriosus include:
1. Medication
Nonsteroidal anti-inflammatory drugs (NSAIDs) such as indomethacin or paracetamol help constrict the patent ductus arteriosus. They are most effective if started early in the newborn period. However, medication is only effective in premature infants and cannot be used in patients with kidney problems or bleeding tendencies.
2. Surgery
Surgical thoracotomy on the side of the chest to ligate and cut the patent ductus arteriosus (PDA ligation) can be performed. Surgery must be done by a specialized thoracic, cardiac, and vascular surgeon to avoid complications,
such as lymphatic injury or vocal nerve damage, and requires close postoperative monitoring in the intensive care unit (ICU).
3. Cardiac catheterization
Transcatheter PDA device closure involves catheterization through the femoral vessel to place a device resembling a disc to close the patent ductus arteriosus. The advantages include no surgical wound, faster recovery, and fewer complications. However, it must be performed in a catheterization lab using fluoroscopy and is not suitable for all types of patent ductus arteriosus.
Patent ductus arteriosus can be completely cured, but not all types should be closed in certain heart diseases such as cyanotic heart disease Tetralogy of Fallot, where the patent ductus arteriosus helps reduce cyanosis.
Therefore, a detailed echocardiogram examination by a pediatric cardiologist is recommended before deciding on treatment.
Dr. Kantima Pongpichayasiri
Pediatric Cardiologist, Phyathai 2 Hospital
