Are patients with thrombophilia and previous venous thromboembolism at higher risk to arterial thrombosis?

Background: Whether thrombophilic disorders, which are established risk factors for venous thromboembolism (VTE), also increase the risk of arterial thrombosis is still unknown.

Methods: We analyzed data from 1081 consecutive patients (649 F/432 M, 16-93 years of age) with previous VTE registered in the MAISTHRO (MAin-ISar-THROmbosis) database with regard to arterial thrombotic events and contributing risk factors. Screening for thrombophilia included testing for factor V Leiden and prothrombin G20210A mutation, antiphospholipid antibodies and activities of factor VIII, protein C, protein S and antithrombin.

Results: Of the entire study cohort, 40 patients (3.7%) had a prior myocardial infarction (MI), and 41 (3.8%) suffered a stroke. Other arterial thrombotic events were rare. Elevated factor VIII levels were more prevalent in MI patients than in controls (44.4 vs. 25.9%, p=0.044), but after adjusting for the traditional cardiovascular risk factors, this relationship was no longer significant. We observed a higher rate of lupus anticoagulant in MI patients with an adjusted odds ratio of 3.3 (95%CI 0.84-12.8, p=0.090). No difference in any other tested thrombophilia was observed in patients with MI or stroke relative to those without.

Conclusions: The cumulative incidence of arterial thrombotic events in VTE patients is low, and the inherited thrombophilias do not seem to substantially increase the risk of arterial thrombosis.