Natural evolution of patent ductus arteriosus in the extremely preterm infant

Objective: The persistence of the patent ductus arteriosus (PDA) is frequently encountered in very preterm infants. Neither preventive nor curative treatments of PDA have been shown to improve the outcome of these infants. Since no consensus on optimal treatment of PDA is established, we evaluated the rate of spontaneous PDA closure in infants born before 28 weeks of gestation.

Patients and methods: We studied a retrospective cohort of 103 infants (gestational age 24-27 weeks) admitted to our neonatal intensive care unit from 1 June 2008 to 31 July 2010. Maternal and neonatal characteristics were collected. The PDA was defined by the persistence of ductal patency after 72 h and was followed up by regular echocardiography.

Results: Twelve infants died within the first 72 h and were excluded from the analysis. Among 91 infants analysed, 8 (9%) closed their ductus arteriosus before 72 h and the ductus could not be determined patent in 13. Of the 70 infants with a PDA still persistent, one underwent surgical ligation and echocardiography showed spontaneous closure in 51 (73%) of them. In the remaining 18 infants, the date of PDA closure could not be determined either because of their death (n=11) or due to discharge (n=7). Overall, a spontaneous closure of the ductus arteriosus was observed in 59 of the 91 infants.

Conclusions: We have to question whether exposure to the risks of therapeutic interventions targeted for ductal closure is warranted since a PDA closes spontaneously in at least 73% of infants born before 28 weeks.