Previous data have suggested that higher Factor VIII levels, VWF (von Willebrand Factor) levels and lower Protein C levels observed in African populations may account for some of the racial differences in thrombotic risk.20 In addition, recent data have highlighted important racial differences in platelet reactivity to thrombin, with platelets from Black patients commonly exhibiting polymorphisms in the PAR (protease-activated receptor)-4 that are associated with a markedly enhanced aggregation response to thrombin.21