Abstract 16117: Sildenafil Reduces Pulmonary Vascular Resistance in Patients With Single Ventricular Physiology
Background: In patients with single ventricular physiology, risk of Fontan operation increases with higher pulmonary vascular resistance (PVR). Furthermore, in patients after Fontan operation, even mildly increased PVR may result in increases in central venous pressure and decreases in cardiac output and exercise capacity. It remains undetermined whether pulmonary vasodilators such as phosphodiesterase 5 inhibitors can indeed decrease PVR in patients with single ventricular physiology before and/or after Fontan operation.
Objective: The purpose of this study was to investigate if sildenafil can reduce PVR in patients with single ventricle physiology.
Methods: This was a prospective, multicenter study. 31 patients with PVR >2.5 Wood unit.m2 before or after Fontan operation were enrolled. Subjects consisted of 5 patients before Glenn, (median age 1.6 years), 9 patients after Glenn but before Fontan (median age 3.8 years), and 17 patients after Fontan operation (median age 14 years, 3.8±2.2years after Fontan). Cardiac catheterization was performed before and 15±13 months after administration of oral sildenafil. Six minutes walk test was used to evaluate exercise capacity.
Results: In patients before Glenn, PVR before sildenafil (4.6±1.5 Wood U.m2) decreased significantly (p=0.01) to 2.0±0.5Wood U.m2 after sildenafil. In patients after Glenn, PVR before sildenafil (3.1±0.5 Wood U.m2) decreased significantly (p=0.01) to 2.1±1.2 Wood U.m2after sildenafil. In patients after Fontan, PVR before sildenaphil (4.2±1.7) decreased significantly (p<0.001) to 2.3±0.8 U.m2 after sildenafil, mean pulmonary artery pressure decreased from 16.5±5.0 to 12.8±3.5 mmHg (p=0.01), SpO2 at rest increased from 92±4 % to 94±4% (p=0.02) and 6 minutes walk distance increased from 410±70m to 487±54m (p=0.04). Major side effects were not observed in any patients.
Conclusions: Sildenafil reduces PVR in patients with single ventricle physiology before and after Fontan operation. Sildenafil may increase exercise capacity in patients after Fontan operation. Whether sildenafil reduces morbidity at long-term after Fontan remains to be clarified.
- © 2013 by American Heart Association, Inc.