Patent Ductus Arteriosus: Evidence for and against Treatment

Relationship between treatment times in randomized PDA trials and the occurrence of common neonatal morbidities. Each trial type (prophylactic or symptomatic) entered infants into an initial early treatment or control (no treatment) group. Several days later a backup treatment was used to close any remaining clinically significant PDA shunts. These trials can detect morbidities affected by the PDA that present or develop during the interval between initial and backup treatments (ie, during the interval that the ductus is closed in the early group and open in the control group). For example, prophylactic trials have the potential to examine the role of PDA on the incidence of ICH or pulmonary hemorrhage, whereas the symptomatic trials would not be able to examine this relationship. Conversely, the symptomatic trials might be able to examine the relationship between PDA and NEC, whereas the prophylactic trials would be unlikely to do so. Shaded bar represents the postnatal age when a morbidity either develops or is apparent. Shaded bars with ??? represent morbidities that may or may not have their origins during this period. BPD, bronchopulmonary dysplasia.