1. Department of Cardiovascular Surgery, Baystate Medical Center, Springfield, Massachusetts, USA
2. Division of Cardiothoracic Surgery, Missouri Baptist Medical Center, Saint Louis, Missouri, USA
3. Department of Thoracic and Cardiovascular Surgery, Sanger Heart and Vascular Institute, Carolinas Medical Center, Charlotte, North Carolina, USA
4. Division of Cardiac Surgery, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
5. Thoracic and Cardiovascular Surgery, Spectrum Health, Fred and Lena Meijer Heart and Vascular Institute, Grand Rapids, Michigan, USA
6. Department of Cardiac Surgery, Hartford Hospital, Hartford, Connecticut, USA