Objective To determine morbidity, mortality and associated risk factors following patent ductus arteriosus (PDA) ligation in premature infants.

Methods Retrospective case note audit of premature infants referred to a national paediatric cardiothoracic surgical service (2001–2007) with univariate and multivariate analysis of potential risk factors for mortality and morbidity.

Results 125 infants were enrolled (median gestational age 26 weeks (IQR 25–27 weeks), median birth weight 840 g (IQR 730–1035 g)). Referral characteristics were median LA:Ao 1.8 (IQR 1.5–2.0), 80% ventilated, 18.4% continuous positive airway pressure, 70% diuretics and 58% prior treatment with cyclooxygenase inhibitors (COIs). Median age at PDA ligation was 31 days (IQR 25–41 days). Postoperative characteristics were median time to extubation 5 days (IQR 3–10 days), 36.0% corticosteroids, 46.8% domiciliary oxygen and 4.8% vocal cord palsy. The 30-day and 1-year mortality rates were 4.8% and 12.8%, respectively, with neurodisability in 32% of survivors. All deaths occurred in the ventilated group and were mainly attributable to bronchopulmonary dysplasia (BPD). Gestation and fractional inspired oxygen (FiO₂)>60% were significantly associated with 30-day mortality. FiO₂, ventilation, lack of prior COIs and postoperative corticosteroids were significantly associated with 1-year mortality. Preoperative FiO₂>40% and lack of prior COIs retained independent significance for death at 1 year.

Conclusions PDA ligation is well tolerated, with evidence of early benefit. The incidence of neurodisability or death from BPD at 1 year remains high. Increasing preoperative FiO₂ and lack of prior treatment with COIs are associated with increased mortality at 1 year.