1. From the Center for Hemostasis and Thrombosis Research, Tufts Medical Center, Tufts University School of Medicine, Boston, MA (R.R., T.H., G.K., E.K.F., S.E.T., A.S., L.C., A.K.)
2. Inova Center for Thrombosis Research and Translational Medicine, Inova Heart and Vascular Institute, Inova Fairfax Hospital, Falls Church, VA (P.A.G., K.P.B.)
3. Department of Medicine, Division of Cardiology, University of Massachusetts Memorial Medical Center, University of Massachusetts Medical School, Worcester (J.J.R.)
4. Department of Medicine, Division of Cardiology, Tufts Medical Center, Boston, MA (C.D.K.).