... risk factors, increasing Chapter 111. Venous Thrombosis (Part 2) Figure 111- 1 antithrombin, protein C, and protein S deficiencies—increase the risk of recurrent thrombosis by 50% at most. ... Models of thrombosis risk. In each panel, the figure shows the thrombosis (black) potential of each risk factor present during an individual's life and the resultant thrombosis potential ... (red). (From FR Rosendaal: Venous thrombosis: A multicausal disease. Lancet 353:1167, 1999; with permission.) Several acquired risk factors are very strong, causing thrombosis in several percent...