1. Department of Cardiac Surgery, Ludwig Maximilian University Munich, Munich, Germany
2. Department of Thoracic and Cardiovascular Surgery, Faculty of Medicine, Kepler University Hospital Linz, Johannes Kepler University Linz, Linz, Austria
3. Department of Cardiac Surgery, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
4. Department of Cardiac Surgery, Leipzig Heart Centre, University of Leipzig, Leipzig, Germany
5. Department for Cardiac, Thoracic, Transplantation and Vascular Surgery, Medical University of Hannover, Hannover, Germany
6. Department of Thoracic and Cardiovascular Surgery, West-German Heart and Vascular Center Essen, University of Duisburg-Essen, Essen, Germany
7. Faculty of Medicine, Department of Cardiovascular Surgery, Heart Center Freiburg University, University of Freiburg, Freiburg, Germany
8. Department of Cardiovascular Surgery, Mater Dei Hospital, Bari, Italy
9. Department of Cardiac Surgery, INCCI HaerzZenter, Luxembourg, Luxembourg
10. Department of Cardiovascular Sciences, European Hospital, Rome, Italy
11. Department of Cardiac Surgery, Cardiovascular Clinic Bad Neustadt, Bad Neustadt, Germany