1. Department of Cardiac Surgery, Wroclaw Medical University, Poland
2. Department of Cardiovascular and Thoracic Surgery, West Virginia University Heart and Vascular Institute, Morgantown, WV, USA
3. Department of Cardiac Surgery, Klinikum Bogenhausen, Munich, Germany
4. Department of Cardiovascular Surgery, Klinikum Nürnberg, Paracelsus Medical University, Nürnberg, Germany
5. Department of Cardiac and Thoracic Surgery, Klinik für Herzchirurgie Kerckhoff-Klinik, Justus-Liebig-Universität Gießen, Bad Nauheim, Germany
6. Department of Cardiac Surgery, Medical University of Silesia, Katowice, Poland