Study of the Efficacy and Safety of Tezosentan in Patients With Pre-operative Pulmonary Hypertension, Due to Left Heart Disease, Undergoing Open Heart Surgery

Endothelin-1 levels are increased during and after cardiac surgery with cardiopulmonary bypass (CPB), and are associated with many deleterious consequences, including increased pulmonary arterial pressure (PAP), increased pulmonary vascular resistance (PVR), reduced myocardial contractility, and ultimately right ventricular failure. Right ventricular failure during weaning from CPB increases the risk of mortality and morbidity, especially in patients with elevated PAP prior to cardiac surgery. Endothelin receptor antagonists (ERAs) have been shown to decrease PVR and pulmonary arterial pressure (PAP), and improve right ventricular function in patients with pulmonary arterial hypertension. In animal models, ERAs have been shown to decrease the incidence of post-bypass pulmonary hypertensive crises. The primary objective of this trial is to demonstrate that tezosentan, a dual ERA, reduces the incidence of clinically relevant right ventricular failure in patients with pre-operative pulmonary hypertension, due to left heart disease, undergoing CPB.