What is patent ductus arteriosus?
Patent ductus arteriosus (PDA) is a congenital heart defect – a structural heart problem that is present at birth.
Patent ductus arteriosus is an abnormal connection between the aorta and the pulmonary artery in the heart. The pulmonary artery carries blood from the heart’s right lower chamber (ventricle) to the lungs, where it is loaded up with oxygen. From the lungs, the blood returns to the heart’s left ventricle and is pumped out through the aorta to the body.
While the baby is in the womb, the aorta and the pulmonary artery are connected by a temporary blood vessel, the ductus arteriosus, as part of the normal fetal circulation. While in the womb, the baby receives oxygen from the mother’s circulation, so blood does not need to flow through the lungs. The ductus arteriosus streamlines fetal circulation by flowing blood directly to the aorta, bypassing the lungs. After birth, the ductus arteriosus usually seals off so that blood from these two vessels does not mix. In patients with PDA, the ductus arteriosus stays open (patent), and blood can flow from the aorta into the pulmonary artery.
How common is PDA?
Patent ductus arteriosus is one of the most common congenital heart defects. About 3,000 newborns are diagnosed with PDA each year in the United States. Premature babies are more likely to have PDA, and the condition occurs twice as often in girls as in boys.
What problems does PDA cause in an adult?
Because most patients with PDA are diagnosed and treated when they are infants, this is a relatively rare congenital heart defect among adults. Most PDAs in adults are small to moderate; it is unusual to find a large PDA in an adult. Symptoms of untreated PDA in an adult include shortness of breath and heart palpitations. An adult with untreated PDA is at high risk for bacterial endocarditis, an infection of the lining of the heart, valves, or arteries; an enlarged heart (cardiomyopathy); pulmonary hypertension (high blood pressure in the lungs); congestive heart failure; and death.
How is PDA diagnosed in an adult?
Shortness of breath, heart palpitations and a heart murmur heard through the stethoscope will give the physician cause to suspect a heart defect and order some specific testing. This may include:
- An echocardiogram: an ultrasound of the heart that clearly shows the heart’s structure and size. Doppler can also be used to assess the direction and velocity of blood flow through the PDA.
- An electrocardiogram (ECG): a recording of the heart’s electrical activity that helps the physician detect abnormalities in the heart rhythm.
- Oximetry (which can be obtained on both fingers and toes): a noninvasive procedure to measure the amount of oxygen in the blood and can identify patients in whom pulmonary hypertension has advanced and resulted in the reversal of blood flow through the PDA.
How is PDA treated in adults?
Closure of the defect is generally recommended (as long as advanced pulmonary hypertension is not present) because of the high risk for cardiac complications and early death related to PDA. Closing the PDA can reduce complications, restore normal circulation, eliminate symptoms and reduce the risk of death.
An open surgical procedure was the standard for decades. In this procedure, the surgeon opens the chest and closes the opening with stitches or permanent titanium clips. Today, adult congenital heart disease experts prefer to reserve an open surgical procedure for those patients with large PDAs. More than 95 percent of PDAs can now be closed by catheter-based techniques.
Video-assisted thoracic surgical (VATS) repair is a newer approach for repairing PDAs. This is a minimally invasive technique in which the surgeon operates through a small incision in the chest using video guidance to perform the repair. VATS combines the advantages of a surgical repair with the benefits of a small-incision approach.
Transcatheter occlusion is the least invasive option for closing a PDA and has become the procedure of choice for PDA repair. In this procedure, a single or multiple coils or a fitted plug is delivered to the site of the PDA by a catheter. The device is positioned in the opening between the two blood vessels and released from the catheter. The plug or coil expands to occlude (block) the pathway; the plug device acts like a drain-stopper to block the opening. More than 85 percent of patients have complete occlusion of the defect within one year of the procedure.
Repairing a PDA in an adult is a more complicated procedure than performing the procedure in children. Adults with PDAs should be under the care of an adult congenital heart disease specialist with experience in treating this particular defect. The specialist will evaluate all considerations, such as the size of the PDA, complications related to the PDA and the patient’s overall health, to make a recommendation on which approach is most likely to have the best outcome. Today, devices and techniques have advanced to the point that percutaneous closure should be the first choice for almost all patients.
What is the prognosis after PDA closure?
Closing the PDA restores normal circulation to the heart and reduces the risk of endocarditis, pulmonary hypertension, aneurysm formation and death. But closing the defect may not reverse the damage already done to the heart, such as congestive heart failure, pulmonary vascular disease or calcium deposits at the site of the defect. Endocarditis prophylaxis (antibiotics) is recommended for 6 months following closure of a PDA or for life if any residual defect is present.
Patients with repaired PDAs should remain under the care of a cardiologist experienced in adult congenital heart problems.
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Krasuski R, Patent Ductus Arteriosus Closure. J Interven Cardiol. 2006;19:S60–S66.
Tatebe S, Tatenos A, Niwa K, Matsuo K. Clinical Features of Patent Ductus Arteriosus in Adults Treated with Surgery: Comparison with PDA in Children. Pediatric Cardiology and Cardiac Surgery 2003;19(5):485-490.
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