1. Department of General, Visceral and Cancer Surgery; Transplant Center Cologne; University of Cologne; Cologne Germany
2. Institute for Clinical Transfusion Medicine; Transplant Center Cologne; Merheim Medical Center; Cologne General Hospital; Cologne Germany
3. Transplant Center Cologne; Merheim Medical Center; Cologne General Hospital; Cologne Germany
4. Renal Division; Department of Medicine; Transplant Center Cologne; University of Cologne; Cologne Germany
5. Institute of Medical Statistics, Informatics and Epidemiology; University of Cologne; Cologne Germany