1. Department of Thoracic Surgery, ‘Olympion’ General Clinic, 26443 Patras, Greece
2. Department of Thoracic Surgery, University Medicine Essen-Ruhrlandklinik, 45239 Essen, Germany
3. Department of Cardiothoracic and Vascular Surgery, Westpfalz-Klinikum, 67655 Kaiserslautern, Germany
4. Department of Thoracic Surgery, Inselspital, Bern University Hospital, University of Bern, 3012 Bern, Switzerland
5. Department of Cardiothoracic Surgery, Attikon University Hospital of Athens, 12462 Athens, Greece