Patent ductus arteriosus: an overview

Patent ductus arteriosus (PDA) is one of the most common congenital heart defects, accounting for 5%-10% of all congenital heart disease in term infants. The occurrence of PDA is inversely related to gestational age and weight, with an even greater incidence in preterm infants. The maintenance of ductal patency is essential for the normal development of the fetus. In the neonate, however, persistent patency of the ductus arteriosus (DA) is associated with significant morbidity and mortality. Normally, at birth, the DA constricts, resulting in intraluminal ischemic hypoxia, which eventually leads to closure and remodeling of the ductus. PDA in term infants is usually associated with a functional defect, whereas in preterm infants it is associated with immaturity. Normal physiologic mechanisms contributing to closure - oxygen tension and decreased prostaglandins-are altered in prematurity. Clinical signs of ductal patency include murmur, tachycardia, bounding peripheral pulses, and congestive heart failure and associated symptoms. Symptoms are not always present; therefore, diagnostic imaging is critical if a PDA is suspected on clinical grounds. Three management strategies are currently available for PDA: fluid restriction and diuretics (as clinically appropriate), medical intervention, and surgical ligation. Pharmacologic closure can be achieved via administration of intravenous indomethacin or ibuprofen lysine. While both agents have shown similar efficacy, ibuprofen lysine has demonstrated an improved safety profile, particularly in terms of renal effects, compared to indomethacin.