1. From the Pulmonary Hypertension Program (J.N., V.G., R.M., A.H., L.W., E.D.M.), Division of Cardiac Surgery, Department of Surgery (J.N., I.M.R., D.B.R.), and Department of Pharmacology (D.S., C.S.A., P.E.L., J.R.B.D.), University of Alberta, Alberta, Edmonton, Canada; and Section of Cardiology, Department of Medicine, University of Chicago, Chicago, Ill (S.L.A.).