1. Division of Hematology and Hemostasis, Department of Medicine I, Medical University of Vienna, Vienna A-1090, Austria
2. Karl Landsteiner Institute of Thrombosis Research, Vienna A-1020, Austria
3. Center for Medical Statistics, Informatics and Intelligent Systems, Institute of Clinical Biometrics, Medical University of Vienna , Vienna A-1090 , Austria
4. Division of Angiology, Department of Medicine, Medical University of Graz , Graz A-8010 , Austria