1. Department of Thoracic and Cardiovascular Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
2. Department of Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
3. Department of Cardiac Surgery, European Interbalkan Medical Center, Thessaloniki, Greece
4. Department of Cardiac Surgery, Chirurgisches Klinikum München Süd, Munich, Germany