1. Department of Cardiovascular Surgery, Faculty of Medicine, Heart Centre Freiburg University, University of Freiburg, Freiburg, Germany
2. Cardiac Surgery Unit, Cardio-Thoraco-Vascular Department, S. Orsola Hospital, University of Bologna, Bologna, Italy
3. Cardiovascular Surgery Department, Institut Clínic Cardiovascular, Hospital Clínic de Barcelona, University of Barcelona Medical School, Barcelona, Spain
4. Innsbruck Medical University, University Clinic for Cardiac Surgery, Innsbruck, Austria
5. Department of Thoracic and Cardiovascular Surgery, West-German Heart and Vascular Center Essen, University Duisburg-Essen, Essen, Germany
6. Department of Vascular Surgery, San Filippo Neri Hospital, Rome, Italy
7. Department of Cardio-Thoracic Surgery, Erasmus Medical Center, Rotterdam, Netherlands
8. Department of Cardiac Surgery, European Hospital, Rome, Italy
9. Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic, Cleveland, OH, USA
10. Department of Cardiovascular Surgery, University Hospital Bern, Bern, Switzerland