1. Division of Cardiology (A.S.N., S.A.M.K., E.J.D., L.A.E., H.C.H., J.G., A.C.F.), Hospital of the University of Pennsylvania, Philadelphia.
2. Penn Cardiovascular Outcomes, Quality, and Evaluative Research Center (A.S.N., L.Y., N.Y., S.A.M.K., E.J.D., L.A.E., N.D.D., P.W.G., J.G., A.C.F.), University of Pennsylvania, Philadelphia.
3. Leonard Davis Institute of Health Economics (A.S.N., L.Y., S.A.M.K., E.J.D., L.A.E., N.D.D., P.W.G., J.G., A.C.F.), University of Pennsylvania, Philadelphia.
4. Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA (S.A.M.K., P.W.G., J.G.).
5. Duke Clinical Research Institute, Durham, NC (S.V.).
6. Lahey Hospital and Medical Center, Burlington, MA (S.J.B.).
7. St. Francis Hospital, Roslyn, New York (D.J.C.).
8. Division of Cardiac Surgery (N.D.D., J.E.B.), Hospital of the University of Pennsylvania, Philadelphia.