1. Department of Surgery; Medical University of Vienna, General Hospital; Vienna Austria
2. Department of Surgery I; Rudolfstiftung Hospital; Vienna Austria
3. Department of Visceral, Transplantation and Thoracic Surgery; Medical University Innsbruck; Austria
4. Department of Visceral Surgery and Medicine; University Hospital Inselspital Bern; Bern Switzerland
5. Department of Gastroenterology and Hepatology; Medical University of Vienna, General Hospital; Vienna Austria
6. Department of Cardiac Surgery; Medical University of Vienna, General Hospital; Vienna Austria