RESUMO
The contribution of prothrombotic genetic risk factors in the pathogenesis of premature acute myocardial infarction (MI) is controversial. We examined the prevalence of prothrombotic polymorphisms (G1691A of factor V gene [FV Leiden] and G20210A of prothrombin [FII] gene), deficiencies of natural anticoagulants (protein C, protein S and antithrombin III) and antiphospholipid syndrome (APS) in patients with early ST-segment elevation MI (STEMI). We recruited 255 consecutive patients who had survived a STEMI ≤ 35 years of age (224 men). The control group consisted of 400 healthy individuals matched with cases for age and sex. G20210A polymorphism of FII gene was more frequent in young patients than in controls (7.4 vs. 3.5%, p = 0.023). The odds ratio (OR) for STEMI for carriers versus non-carriers was 2.239 (95% CI 1.102-4.250). The adjusted OR for major cardiovascular risk factors was 2.569 (95% CI 1.086-6.074). The risk was increased by 22-fold (95% CI 9.192-66.517) when G20210A polymorphism was present in combination with smoking. There was no difference in the prevalence of FV Leiden between patients and controls (7.8 vs. 6.5%, p = 0.512). There was only one patient (0.4%) with protein C deficiency and one with APS (0.4%). G20210A polymorphism of FII gene may be associated with increased risk of premature STEMI and the risk increases substantially when smoking is present. The contribution of other prothrombotic disorders such as deficiencies of protein C, protein S and antithrombin III and APS was minimal in this cohort.
