1. Department of Cardiothoracic Surgery University of Pittsburgh Pittsburgh Pennsylvania USA
2. Division of Cardiac Surgery, Brigham and Women's Hospital Harvard Medical School Massachusetts Boston USA
3. Division of Cardiac Surgery Yale School of Medicine New Haven Connecticut USA
4. Department of Cardiothoracic Surgery, School of Medicine Stanford University California Stanford USA
5. Division of Cardiac Surgery, Department of Surgery Ohio State University Medical Center Ohio Columbus USA
6. Division of Thoracic and Cardiovascular Surgery University of Florida Gainesville Florida USA
7. Division of Cardiovascular Surgery University of Pennsylvania Philadelphia Pennsylvania USA
8. Division of Cardiothoracic Surgery, Massachusetts General Hospital (MGH) Harvard Medical School Massachusetts Boston USA
9. Department of Cardiac Surgery University of Michigan Medical School Ann Arbor Michigan USA
10. Department of Medicine University of North Carolina Chapel Hill North Carolina USA