Active versus restrictive ligation strategy for patent ductus arteriosus - A retrospective two-center study of extremely preterm infants born between 22 + 0 and 25 + 6 weeks of gestational age.

Background: Patent ductus arteriosus (PDA) in premature infants is associated with adverse clinical outcomes. Mode and timing of treatment are still controversial. Data are limited in the most extremely premature infants <26 weeks of gestational age (GA), where clinical problems are most significant and patients are most vulnerable.

Aims: To investigate whether different approaches to surgical closure of PDA in two large Swedish centers has an impact on clinical outcomes including mortality in extremely preterm infants born <26 weeks GA.

Study Design: Retrospective, two-center, cohort study.

Subjects: Infants born at 22-25 weeks GA between 2010 and 2016 at Uppsala University Children's Hospital (UUCH; n = 228) and Queen Silvia Children's Hospital Gothenburg (QSCHG; n = 220).

Main Outcome Measures: Survival, bronchopulmonary dysplasia (BPD), and retinopathy of prematurity (ROP).

Results: Surgical closure of PDA was more common and performed earlier at QSCHG (50 % vs 16 %; median age 11 vs 44 days; p < 0.01). Survival was similar in both centres. There was a higher incidence of severe BPD and longer duration of mechanical ventilation at UUCH (p < 0.01). There was a higher incidence of ROP, IVH and sepsis at QSCH (p < 0.05, p < 0.01 and p < 0.01). A sub-group analysis matching all surgically treated infants at QSCHG with infants at UUCH with the same GA showed similar results as the total cohort.

Conclusion: Earlier and higher rate of surgical PDA closure in this cohort of extremely preterms born <26 weeks GA did not impact mortality but was associated with lower rates of severe BPD and higher rates of severe ROP.