1. From the Baylor Heart and Vascular Institute (W.C.R., T.J.V., J.M.K.) and the Departments of Pathology (W.C.R.), Internal Medicine (Division of Cardiology) (W.C.R.), and Cardiothoracic Surgery (R.F.H., A.C.H., G.J.M., B.L.H.), and Institute for Health Care Research and Improvement (G.F.), Baylor Health Care System, Baylor University Medical Center, Dallas, TX; and the Department of Statistical Science (G.F.), Southern Methodist University, Dallas, TX.