1. From the Pulmonary Vascular Disease Center, Department of Medicine, University of Pittsburgh Medical Center, Pa (H.C.C.); Pulmonary Hypertension Program and Division of Pulmonary and Critical Care Medicine (P.M.H.), Johns Hopkins Medical Institutions, Baltimore, Md; Pulmonary Hypertension Program, Department of Medicine (Cardiology), University of Alberta, Alberta, Edmonton, Canada (E.D.M.); and Pulmonary Vascular Research Institute, Chicago, Ill (H.C.C., E.D.M., P.M.H.).