Associations between high factor VIII and low free protein S levels with traditional arterial thrombotic risk factors and their risk on arterial thrombosis: Results from a retrospective family cohort study

High FVIII and low free protein S levels seemed to be mild risk factors for arterial thrombosis. High FVIII levels were particularly observed in relatives with traditional arterial thrombotic risk factors. Free protein S levels were not influenced by these thrombotic risk factors. This assumes that low free protein S levels were genetically determined.