1. Department of Cardiac and Thoracic Vascular Surgery, Philipps-University Hospital Marburg, Baldingerstraße, Marburg, Germany
2. Department of Cardiac and Vascular Surgery, Klinikum Karlsburg, Heart and Diabetes Center Mecklenburg-Western Pommerania, Karlsburg, Germany
3. Department of Cardiac Surgery, Herz-Kreislauf-Zentrum, Rotenburg an der Fulda, Rotenburg a. d. F., Germany