Relationship between Duration of Infant Exposure to a Moderate-to-Large Patent Ductus Arteriosus Shunt and the Risk of Developing Bronchopulmonary Dysplasia or Death Before 36 Weeks

Objective This study was aimed to examine the relationship between duration of infant exposure to a moderate-to-large patent ductus arteriosus (PDA) shunt and the risk of developing bronchopulmonary dysplasia (BPD) or death before 36 weeks (BPD/death). Study Design Infants <28 weeks' gestation who survived >= 7 days ( n = 423) had echocardiograms performed on day 7 and at planned intervals. Results In multivariable regression models, BPD/death did not appear to be increased until infants had been exposed to a moderate-to-large PDA for at least 7-13 days: OR (95%CI) (referent = closed or small PDA): moderate-to-large PDA exposure for <7 days: 0.38 (range, 0.10-1.46); for 7 to 13 days = 2.12 (range, 1.04-4.32); for >= 14 days = 3.86 (range, 2.15-6.96). Once the threshold of 7 to 13 days had been reached, additional exposure (>= 14 days) did not significantly add to the increased incidence of BPD/death: (referent exposure = 7-13 days) exposure for 14 to 27 days = 1.34 (range, 0.52-3.45); for 28 to 48 days = 2.34 (range, 0.88-6.19); for >= 49 days = 1.80 (range. 0.59-5.47). A similar relationship was found for the outcome of BPD-alone. Conclusion Infants < 28 weeks' gestation required at least 7 to 13 days of exposure to a moderate-to-large PDA before a significant increase in the incidence of BPD/death was apparent. Once this threshold was reached additional exposure to a moderate-to-large PDA did not significantly add to the increased incidence of BPD/death.