Cardiovascular Effects of Sildenafil in Neonates and Infants with Congenital Diaphragmatic Hernia and Pulmonary Hypertension

Abstract

Background: Pulmonary hypertension is a common problem in patients with congenital diaphragmatic hernia (CDH). In a subset of these patients, pulmonary hypertension persists despite optimized ventilatory management and supportive care. Sildenafil, a phosphodiestrase V inhibitor, has been used in the treatment of pulmonary hypertension in adults and children. Cardiovascular effects of sildenafil in patients with CDH and pulmonary hypertension are not known. Objective: To describe the changes in cardiovascular and respiratory parameters in newborn infants with CDH and persistent pulmonary hypertension refractory to inhaled nitric oxide (iNO) during the first 2 weeks of sildenafil administration. Methods: Retrospective data analysis of seven patients with CDH (birth weight = 2,573 ± 1,019 g; gestational age = 35.6 ± 4.3 weeks) receiving oral sildenafil for pulmonary hypertension refractory to iNO. Findings of serial echocardiograms and data on cardiovascular and respiratory status were assessed. Results: Right cardiac output increased and left cardiac output tended to increase 1.5–4 h after initiation of sildenafil and the increase was sustained throughout the study. Echocardiographic indices of pulmonary hypertension showed an apparent reduction in abnormally high pulmonary vascular resistance. Systemic blood pressure tended to decrease. Shortening fraction did not change. Ventilatory index and the need for iNO tended to decrease in the five surviving infants. Conclusions: These preliminary findings suggest that sildenafil may improve cardiac output by reducing pulmonary hypertension refractory to iNO in patients with CDH.