Late closure of the ductus arteriosus using indomethacin in the preterm infant.

Several studies have shown a lack of effect of indomethacin therapy for the closure of a patent ductus arteriosus (PDA) in premature infants over 14 days of postnatal age. In this report we describe two cases in which a hemodynamically significant PDA was closed with indomethacin in preterm infants over 20 days of age. The response to indomethacin may be more related to postconceptual age than to actual postnatal age. We suggest that intravenous indomethacin therapy should be attempted before surgical ligation is performed in those premature infants under 34 weeks postconceptual age who have a hemodynamically significant patent ductus arteriosus.