Elevated Von Willebrand Factor Antigen Levels are an Independent Risk Factor for Venous Thromboembolism: First Report from North India

Elevated levels of coagulation factor VIII have been associated with increased risk for venous thromboembolism (VTE). The role of Von Willebrand factor (VWF) in VTE is unclear. In this study, we investigated the association of raised levels of VWF and factor VIII in patients with VTE. 100 patients of VTE and 100 age and gender matched controls were tested for levels of VWF antigen, coagulation factor VIII:C, Protein C, Protein S, antithrombin, antiphospholipid antibodies and for the presence of Factor V Leiden mutation. The mean level of VWF was significantly higher amongst patients of VTE (177.3 IU/dl) when compared to controls (129.7 IU/dl) ( P < 0.001). Similarly, the mean level of FVIII:C was significantly higher amongst patients of VTE (199.1 IU/dl) when compared to controls (145.2 IU/dl) ( P < 0.001). On logistic regression analysis, after adjusting for FVIII:C, Protein S, factor V Leiden and trauma, the association of raised VWF with VTE remained significant ( P = 0.001). Similarly higher levels of FVIII:C persisted to have an independent association with VTE ( P = 0.004). Both, higher levels of VWF and FVIII:C levels, are independently associated with VTE.