Sildenafil increases systemic saturation and reduces pulmonary artery pressure in patients with failing Fontan physiology

Objective: The purpose of this study was to investigate the effect of sildenafil in patients with failing Fontan physiology. Design: A retrospective chart review was performed to compare history and available data in patients with Fontan circulations before and after starting sildenafil. The paired and unpaired Student's t-tests were used for statistical analyses. Patients: Six patients at our institution with Fontan physiology, persistent symptoms of cyanosis or effusion, and poor hemodynamics as measured in the catheterization laboratory were placed on sildenafil. One patient was not included in the analysis because of insufficient length of treatment. All patients had symptoms of failing Fontan hemodynamics with either persistent cyanosis or effusions. In this group, the mean pulmonary artery pressure was greater than 15 mm Hg (17.4 ± 1.5 mm Hg) with mean estimated pulmonary vascular resistance of 3.5 ± 1.0 Wood units × m² prior to starting sildenafil. Results: Sildenafil significantly increased the systemic arterial oxyhemoglobin saturation in this group (82.8 ± 7.3% pre-treatment vs. 91.0 ± 5.5% post-treatment, P = .017). In the four out of five patients who have had follow-up catheterizations, there was a significant decrease in pulmonary artery pressure (17.4 ± 1.5 mm Hg pre-treatment vs. 13.8 ± 2.1 mm Hg post-treatment, P = .018) and in estimated pulmonary vascular resistance pre- and post-sildenafil treatment (3.5 ± 1.0 Wood units × m² pre-treatment vs. 2.0 ± 0.4 Wood units × m² post-treatment, P = .031). Conclusions. : Sildenafil may be a useful adjunct to therapy in patients with failing Fontan physiology likely through its function as a pulmonary vasodilator.