[1] Univ Hosp Bonn, Dept Gen Visceral Thorac & Vasc Surg, Bonn, Germany
[2] Univ Hosp Bonn, Inst Expt Haematol & Transfus Med, Bonn, Germany
[3] Univ Hosp Bonn, Inst Med Biometr Informat & Epidemiol, Bonn, Germany
[4] St Elisabeth Hosp Leipzig, Dept Gen & Visceral Surg, Leipzig, Germany