1. Department of Cardiac Surgery, Heart Institute Lahr/Baden, Lahr, Germany
2. Department of Cardio-Thoracic Surgery, Faculty of Medicine, Alexandria University, Alexandria, Egypt
3. Department of Plastic-, Aesthetic-, Hand- and Reconstructive Surgery, Hannover Medical School, Hannover, Germany
4. Faculty of Health, School of Medicine, University of Witten Herdecke, Witten, Germany