1. From the Departments of Cardiothoracic Surgery (J.M.S., S.K.S., D.L.J., B.A.R., R.C.R.) and Medicine (R.T.Z.), Division of Pulmonary and Critical Care Medicine, Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford Hospital and Clinics, Stanford, CA; and Department of Surgery, Division of Cardiothoracic Surgery, Baylor College of Medicine and Center for Cardiac Support, Texas Heart Institute, Houston, TX (H.R.M.).