Second Course of Therapy for Resistant Patent Ductus Arteriosus (PDA)

Patency of the ductus arteriosus (PDA) is functionally essential for fetal circulation, however persistence of ductal patency postnatally may have significant adverse hemodynamic effects in the neonate. Medical therapy for PDA predominantly involves the administration of one of two non-steroidal anti-inflammatory drugs: indomethacin or ibuprofen. Both of these therapies have been shown to be successful in mediating ductal closure in approximately 70% of treated infants. However, the need for a second course of treatment for PDA closure remains quite common. The investigators hypothesize that, because of small differences between the two drugs, a greater percentage of infants who did not respond to a first course of therapy with indomethacin will respond to a second course with ibuprofen than to a repeat course of indomethacin. As such, the investigators aim to compare secondary therapy with a repeat course of indomethacin to secondary therapy with ibuprofen in infants whose ductus remained patent after a first course of therapy with indomethacin.