Hypercoagulability and the risk of myocardial infarction and ischemic stroke in young women

Background: Myocardial infarction (MI) and ischemic stroke (IS) are acute forms of arterial thrombosis and share some, but not all, risk factors, indicating different pathophysiological mechanisms. Objective: This study aims to determine if hypercoagulability has a differential effect on the risk of MI and IS. Patients and methods: We reviewed the results from the Risk of Arterial Thrombosis in Relation to Oral Contraceptives study, a population-based case-control study involving young women (< 50 years) with MI, non-cardioembolic IS and healthy controls. From these data, relative odds ratios (ORIS/ORMI) and their corresponding confidence intervals for all prothrombotic factors that were studied in both subgroups were calculated. Results: Twenty-nine prothrombotic risk factors were identified as measures of hypercoagulability. Twenty-two of these risk factors (21/29, 72%) had a relative odds ratios > 1; for 12 (41%), it was > 2; and for 5 (17%), it was > 2.75. The five risk factors with the largest differences in associations were high levels of activated factor XI (FXI) and FXII, kallikrein, the presence of lupus anticoagulans, and a genetic variation in the FXIII gene. Conclusion: In young women, prothrombotic factors are associated more with the risk of IS than with MI risk, suggesting a different role of hypercoagulability in the mechanism leading to these two diseases.