1. Department of Cardiac Surgery, University of Michigan, Ann Arbor (D.S.L., L.C., R.L.P.)
2. Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative, Ann Arbor, MI (D.S.L., L.C., R.J.S., R.L.P.).
3. Heart and Vascular Institute, Henry Ford Macomb Hospitals, Clinton Township, MI (S.D.H.).
4. Department of Cardiac Surgery, Bronson Methodist Hospital, Kalamazoo, MI (A.D.).
5. Department of Internal Medicine, University of Michigan, Ann Arbor (C.E.C.)
6. VA Ann Arbor Healthcare System and Department of Internal Medicine, University of Michigan, Ann Arbor (S.L.K.)
7. Outcomes Research and Assessment Group, Duke Clinical Research Institute, Duke University, Durham, NC (D.T., R.A.M.)
8. Department of Biostatistics, University of Michigan, Ann Arbor (M.Z.)
9. Department of Biostatistics and Bioinformatics, Duke University, Durham, NC (R.A.M.)