Background: Haemodynamically significant persistent ductus arteriosus (PDA) with left-to-right shunting causes overload of the pulmonary circulation and results in prolonged mechanical ventilation and oxygen dependence. Among other options, pharmacological closure using cyclooxygenase inhibitors remains popular among neonatologists. The purpose of the study was to assess the importance of factors affecting the outcome of the aforementioned strategy.
Methods: Charts of neonates with respiratory failure treated with indomethacin for PDA were retrospectively analyzed. Patients with other heart abnormalities and those with delayed PDA therapy were excluded.
Results: 83 patients met the inclusion criteria. The median birth weight was 1000 g (interquartile range--IQR 800-1320), and gestational age was 27 weeks (IQR 26-30). The overall success rate of primary treatment with indomethacin was 57%. Surgical PDA ligation was performed in 32%. Factors which contributed significantly (p < 0.05) to the failure of indomethacin treatment were: each 10 mL kg(-1) of intravenous fluid administration that exceeded the total amount of 100 mL kg(-1) 24h(-1), odds ratio (OR) 1.12; a PDA diameter/body mass index (OR 1.93); and gestational age (OR 0.78). In a multivariate model, the following factors were found significant: gestational age OR 0.76 (95% confidence interval 0.61-0.95) and i.v. fluid excess OR 1.14 (95% CI 1.02-1.27). In patients with primary treatment failure a higher incidence of bronchopulmonary dysplasia (BPD) (67% vs. 36% p = 0.006), and combined BPD or death (72% vs 42.5% p = 0.01) were noted.
Conclusions: Prediction of successful treatment with indomethacin is possible on the basis of gestational age and daily fluid intake. These factors should be considered when considering the risk/benefit of indomethacin therapy.