1. From the Cardiovascular Division, Brigham and Women’s Hospital, Boston, Mass (Y.W., M.S., Z.C., C.S., K.C., A.C.Z., D.I.S.); The Cleveland Clinic Foundation, Cleveland, Ohio (V.U., E.P.); Thrombosis Research Section, Departments of Medicine and Molecular and Human Genetics, Baylor College of Medicine, Houston, Tex (J.L.); and Portola Pharmaceuticals, South San Francisco, Calif (P.A.).