Plasma factor VIII in non-puerperal cerebral venous thrombosis: a prospective case-control study.

Elevated plasma factor VIII (FVIII) is increasingly recognized as an independent risk factor for thrombotic diseases. Our aim was to evaluate the association of increased plasma FVIII with cerebral venous thrombosis (CVT). Forty eight patients with non-puerperal, aseptic CVT were recruited for the study along with 50 age- and gender-matched, healthy controls. Blood samples were collected 3 months after the thrombotic event in patients. Plasma FVIII and fibrinogen levels were measured by a functional clot-based assay. Mean plasma FVIII was significantly higher in patients when compared to controls (235.40 ± 94.5 vs.121.2 ± 28.3IU/dl, p<0.001). Absence of significant elevation of fibrinogen suggested that the increase in FVIII was not due to an acute phase reaction. Elevated FVIII (>170 IU/dl) was associated with >18-fold increase in the risk for non-puerperal CVT (adjusted OR: 18.754, 95% CI 10.2-203.0, p<0.001). Non-O blood groups were more prevalent in CVT patients. Mean FVIII levels were higher in subjects with non-O blood group as compared to those with O blood group (155.16 ± 46.05 vs. 129.09 ± 40.06 IU/dl, p<0.001). Multivariate analysis with logistic regression showed that only elevated FVIII, and not blood group, was significantly associated with CVT. Our study demonstrates that elevated FVIII is an independent risk factor for non-puerperal CVT in an Indian population.