Safety, Pharmacokinetics (PK) and Hemodynamic Effects of Ambrisentan in Single Ventricle Pediatric Patients

Purpose: To evaluate the pharmacokinetics, bioavailability and hemodynamic efficacy of ambrisentan after Fontan surgical palliation of single ventricle heart defects. Study activities and population group: Children undergoing Fontan surgical palliation for single ventricle defects will be eligible for the study. Up to 20 subjects will be enrolled (16 ambrisentan, 4 placebo) and will receive 3 days (3 doses) of ambrisentan starting on post-operative day #1 upon returning from the operating room. Ambrisentan plasma levels will be obtained at specified time points during treatment. Post-operative monitoring lines will be used to measure effects of ambrisentan on hemodynamics and pulmonary / systemic endothelial function.