Common risk factors for both arterial and venous thrombosis.

Arterial and venous thromboses have traditionally been viewed as distinct conditions, with differences in risk factors, pathology and treatment. However, recent epidemiological studies have suggested associations between venous thromboembolism, arterial thromboembolism (myocardial infarction and stroke) and atherosclerosis. While several biological mechanisms might contribute to these associations, common risk factors for both arterial and venous thrombosis probably play the major role. This article summarizes the evidence for shared risk factors (clinical, biochemical and haematological) that supports this conclusion. At a practical level, it is suggested that following routine treatment of venous thromboembolism with a course of anticoagulant drugs, patients should be routinely assessed not only for risk of recurrent venous thromboembolism but also for risk of arterial thromboembolism. Appropriate lifestyle advice and medication (including aspirin) should then be considered.