1 Surgical Research Laboratory, and Section of Hepatobiliary Surgery and Liver Transplantation, Department of Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
2 Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands; Department of Internal Medicine, Division of Thrombosis and Haemostasis, Leiden University Medical Center, Leiden, The Netherlands.