1. Department of Clinical Epidemiology; Leiden University Medical Center; Leiden the Netherlands
2. Einthoven Laboratory for Experimental Vascular Medicine; Leiden University Medical Center; Leiden the Netherlands
3. Department of Haematology; Glasgow Royal Infirmary; Glasgow UK
4. Department of Haematology; Addenbrooke's Hospital; Cambridge UK
5. Department of Medicine I; Medical University of Vienna; Vienna Austria
6. Karl Landsteiner Institute of Thrombosis Research; Vienna Austria