Effect of the factor Xa inhibitor rivaroxaban on arterial thrombosis in wild-type and apolipoprotein E-deficient mice.

Rivaroxaban is a potent and specific direct inhibitor of coagulation factor Xa. Recent studies have highlighted its effectiveness in the prevention of venous thrombosis and embolic stroke due to atrial fibrillation. To evaluate the antithrombotic effects of rivaroxaban in an in vivo model of arterial thrombosis, photochemical vascular injury was induced in wild-type mice by intravenous rose bengal (50 mg/kg body weight [BW]) followed by illumination of the left common carotid artery using a 543 nm helium-neon laser beam. Rivaroxaban, injected concomitantly with rose bengal at doses of 1.0, 1.5, 2.0, or 3.0 mg/kg BW, dose-dependently prolonged the times to first thrombotic occlusion and stable thrombosis. Quantitative analysis of carotid flow curves revealed higher blood volumes passing through the injured artery with increasing rivaroxaban doses (P<0.01 and P<0.001 vs. vehicle for 2.0 and 3.0 mg/kg , respectively), suggesting a dose-dependent effect on vascular patency. Consistently, a significantly higher proportion of mice that received 2.0 and 3.0 mg/kg rivaroxaban exhibited patent carotid arteries at the end of the flow monitoring period compared to vehicle alone (P<0.05 and P<0.001, respectively). Histological analysis showed complete thrombotic arterial occlusion in vehicle-treated mice compared to less thrombotic material in mice injected with 3.0 mg/kg rivaroxaban (P<0.05). Rivaroxaban also prolonged the time to cessation of tail bleeding in a dose-dependent manner, starting at 1.5 mg/kg. Similar findings were obtained in apolipoprotein E-knockout mice. Rivaroxaban may exert beneficial effects by preventing arterial thrombosis and vascular occlusion after endothelial injury.