The effect of sildenafil on evolving bronchopulmonary dysplasia in extremely preterm infants: a randomised controlled pilot study

Objective: Sildenafil has been shown to preserve alveolar growth and lung angiogenesis in a rat model of bronchopulmonary dysplasia. We conducted a proof-of-concept randomised controlled pilot study to assess the feasibility of oral sildenafil treatment in extremely preterm infants with evolving bronchopulmonary dysplasia. Methods: Preterm infants <28 weeks gestational age were eligible if they were mechanically ventilated on day 7 of life. Infants were randomised to a 4-weeks course of either oral sildenafil (3 mg/kg/day) or placebo solution. Pre-discharge cardiorespiratory outcomes and medication side effects were collected. Results: Twenty infants were randomised, 10 received sildenafil (mean gestational age 24 + 5 weeks (SD 4.9 days), mean weight 692 g (SD 98)) and 10 received placebo (mean gestational age 24 + 5 weeks (SD 6.5 days), mean weight 668 g (SD 147)). One infant in the sildenafil group did not receive treatment because of an early pneumoperitoneum. Two infants did not complete the study (transferred out). Of the remaining seven treated infants, three died (two from respiratory-related causes). One infant in the control group died from a non-respiratory cause. Sildenafil did not reduce length of invasive (median 688 versus 227 h) or non-invasive ventilation (median 1609 versus 1416 h). More infants in the sildenafil group required postnatal steroid treatment. One infant developed hypotension following sildenafil administration and was excluded after three doses. Conclusions: In this pilot study, oral sildenafil treatment did not improve any short-term respiratory outcomes in extremely preterm infants.