1. Division of Cardiothoracic Surgery; University of California; San Francisco California
2. Division of Cardiac Surgery; University of Maryland School of Medicine; Baltimore Maryland
3. Duke Clinical Research Institute; Durham North Carolina
4. Division of Cardiothoracic Surgery; Emory University; Atlanta Georgia
5. Division of Thoracic and Cardiovascular Surgery; University of Virginia; Charlottesville Virginia
6. Division of Cardiovascular and Thoracic Surgery; Duke University; Durham North Carolina
7. Division of Cardiothoracic Surgery; University of Pennsylvania; Philadelphia Pennsylvania
8. Department of Thoracic and Cardiovascular Surgery; Cleveland Clinic Foundation; Cleveland Ohio