1. Department of Thoracic and Cardiovascular Surgery, Klinikum Braunschweig, Braunschweig, Germany
2. Department of Cardiac Surgery, University Hospital Pilsen, Pilsen, Czech Republic
3. Department of Cardiovascular Surgery, University Hospital Giessen and Marburg, Giessen, Germany
4. Heart Surgery Department, Pavol Jozef Safarik University Kosice, Kosice, Slovak Republic
5. Cardiovascular Surgery, Byelorussian Center of Cardiovascular Surgery, Minsk, Belarus
6. Cardiovascular, Thoracic and Intensive Care, Mediclin Herzzentrum Coswig, Coswig, Germany