1. Division of Cardiovascular Surgery, The University of Florida, Gainesville, Florida
2. Division of Cardiovascular Surgery, The University of Pennsylvania Health System, Philadelphia, Pennsylvania
3. Division of Cardiac Surgery, West Virginia University Heart and Vascular Institute, Morgantown, West Virginia
4. Duke University Medical Center, Durham, North Carolina
5. Division of Cardiothoracic Surgery, Yale University School of Medicine, New Haven, Connecticut