The Effect of Phosphodiesterase Type 5 Inhibitors on the Development of Retinopathy of Prematurity in Imam Khomeini Hospital's, Ahvaz, Iran Preterm Infants: A Randomized Clinical Trial

Background: Retinopathy of prematurity (ROP) affects premature infants, and it is characterized by the development of vascular proliferation due to hyperoxia, down regulation of Vascular endothelial growth factor(VEGF) and death of endothelial cells. We hypothesized that inhibition of Phosphodiesterase 5 enzyme suppresses retinal vasoconstriction and prevent ROP.

Study Design: 109 newborns with respiratory distress syndrome treated with oxygen with early gestational age (GA) ≤30 weeks and birth weight (BW) ≤1500 g were randomized into two groups, 52 patients in sildenafil and 50 patients in placebo group were studied, Group sildenafil (as case group) and placebo Group (as control group), sildenafil was administered via nasogastric tube. Occurrence of ROP phase 1 as primary outcome and stage 2-5 ROP, duration of mechanical ventilation, oxygen therapy and duration of hospitalization as secondary outcomes were assessed.

Results: There was no differences between the two group in demographic characteristics. ROP phase 1 was seen in 11(22%) and 7(14%) of placebo and interventional group, respectively. Stage 3 ROP was not seen in any of the patients.

Conclusion: Sildenafil therapy did not affect ROP development in premature infants treated with oxygen. May be due to our exclusion criteria (BW less than 1000g) and this fact that there is a high incidence of ROP in extremely low birth weight neonates, we didn’t find any significant difference. More studies with larger population and expanded criteria are needed to find the effect of sildenafil on ROP.