Duration of significant patent ductus arteriosus and bronchopulmonary dysplasia in extremely preterm infants

Objective To demonstrate the association between the duration of significant patent ductus arteriosus (PDA) and bronchopulmonary dysplasia (BPD) in extremely preterm infants. Methods All extremely preterm infants (<29 weeks) treated in our Neonatal Intensive Care Unit from January 2013 to March 2016 were included if their PDA status was confirmed at <7 days of life. Infants with genetic syndromes, complex congenital anomalies and insignificant PDAs were excluded. Total duration of significant PDA was estimated by reviewing serial echocardiograms. Significant PDA was diagnosed using our scoring system that was based upon echocardiographic parameters and clinical status of the infants. Study cohort was divided into four groups based on the duration of significant PDA. Group A-No PDA, Group B-PDA <1-week, Group C- PDA 1–2 weeks, and Group D-PDA >2 weeks. ANOVA and multivariate analysis were performed to compare the groups. Results There were 147 infants with no PDA (Group A), 50, 35, and 41 infants were enrolled in Groups B, C, and D, respectively. There were no differences in maternal and neonatal variables among groups except for the following: maternal smoking, chorioamnionitis, antenatal indomethacin, gestation, birth weight, mode of delivery and incidence of death or BPD. Logistic regression analysis showed that longer duration of significant PDA was associated with higher risk for death or BPD (adjusted OR 1.37, 95% CI 1.03–1.82). Conclusion Longer duration of significant PDA is associated with the higher risk for BPD/death in extremely preterm infants.