Right Ventricular Metabolism in Pulmonary Arterial Hypertension

Current medical therapy for pulmonary arterial hypertension (PAH) is aimed at reducing pulmonary vascular resistance (PVR) but not ameliorating right ventricular (RV) failure, the major cause of death. There are no RV-specific therapies currently available for PAH, in part because the pathophysiology of RV failure is poorly understood. The investigators hypothesize that the RV in PAH develops a distinct metabolic pattern characterized by increased glycolysis, impaired oxidative metabolism and lipid deposition, which are associated with RV failure. Specific Aim 1. To test the hypothesis that the RV in human PAH exhibits lipid deposition, increased glycolysis and impaired fatty acid oxidation. The investigators will measure RV oxidative metabolism and glycolysis in PAH patients and controls using positron emission tomography 11C acetate and \[18F\]fluoro-deoxy-D-glucose imaging and measure myocardial lipid accumulation using magnetic resonance spectroscopy imaging. Specific Aim 2. To test the hypothesis that an abnormal RV metabolic profile is associated with RV dysfunction and reduced exercise capacity in PAH. PET and MRS findings will be correlated with RV function, patient exercise capacity and a blood metabolic profile.