1. Department of SurgeryDivision of TransplantationMedical University of ViennaViennaAustria
2. Department of Internal Medicine IIIDivision of Gastroenterology and HepatologyMedical University of ViennaViennaAustria
3. Department of SurgeryDivision of Thoracic SurgeryMedical University of ViennaViennaAustria
4. Section for Medical StatisticsCentre for Medical Statistics, Informatics, and Intelligent SystemsMedical University of ViennaViennaAustria