1. From the University of Pittsburgh Medical Center, Department of Pathology and Laboratory Medicine (J.L.H.), and University of Pennsylvania School of Medicine, Department of Medicine, Division of Cardiovascular Medicine (T.K., M.W., B.S., E.R.M.) and Department of Surgery, Division of Vascular Surgery (R.F., M.E.M., J.P.C., M.G., D.N., R.M., A.C.), Philadelphia.