[Factor VIII and the risk of arterial thrombosis]

The pathomechanism of acute complications of atheromatosis, i.e. arterial thrombosis, still remains unclear. Conventional cardiovascular risk factors can explain only about 50% of cases of arterial thrombosis. The activation of intrinsic and extrinsic pathways of the coagulation system on damaged atherosclerotic plaque is one of the most important mechanisms. The role of clotting factors in the development of arterial thrombosis is also considered. From among a few clotting factors (V, VIII, XIII), factor VIII arouses interest due to the well-known observation that the morbidity for cardiovascular reasons is less among hemophiliacs than in the general population. A high factor VIII level predicts the occurrence of episodes of venous thromboses, but its role in the pathogenesis of arterial thromboses is still unclear. In clinical studies, a high factor VIII level predicts episodes of stroke, myocardial infarct, and acute lower-limb ischemia over a short period of observation. A high factor VIII level may the cause of about 5% of all episodes of arterial thrombosis. The reasons for elevated factor VIII levels in some persons remain unclear. Although heritability can play an important role, the influence of other factors (e.g. activation of the sympathetic nervous system) has been reported. The pathomechanism is the subject of investigation as well. An explanation for the occurrence of severe complications of arterial thrombosis in patients without significant risk factors may result in the development of methods of detection and prevention.