Background: Although inherited thrombophilias are more common in patients with venous thromboembolism, their influence on the development of myocardial infarction (MI) requires clarification.
Methods and results: To determine whether there are increased frequencies of mutations/polymorphisms in 14 genes potentially causing thrombophilia in patients with no flow-limiting stenoses after MI compared with patients with > or =1 flow-limiting stenosis of >50%, we studied 395 patients (60 with no flow-limiting stenosis) who underwent angiography at approximately 1 month. The mutations/polymorphisms studied included Factor V Leiden, prothrombin variant G20210A, beta-fibrinogen 448 (G/A), endothelial protein C receptor (23-base pair insertion), methyl tetrahydrofolate reductase 677 (C/T), platelet glycoprotein IIIa PlA1/A2, plasminogen activator inhibitor-1 4G/5G, angiotensin II type 1 receptor (A/C), hemochromatosis gene 282 (G/A), nitric oxide synthase (NOS) (3 forms: eNOS, eNOS3, eNOS4), p22 phox of NADPH oxidase C242T, and angiotensin-converting enzyme insertion/deletion polymorphism. The frequencies of Factor V Leiden and the beta-fibrinogen 448 A allele were higher in patients with no flow-limiting stenosis than in patients with > or =1 stenosis (11.7% vs 3.6%, odds ratio [OR] 3.6, 95% CI 1.3-9.4, P =.015; and 42% vs 27%, OR 2.0, 95% CI 1.1-3.5, P =.018, respectively), and there was a trend toward an increased frequency of prothrombin variant G20210A (6.7% vs 2.1%, OR 3.4, 95% CI 0.95-11.8, P =.069). However, in patients with no flow-limiting stenosis after MI the frequencies of the other gene mutations/polymorphisms were not increased. Also, there were no significant interactions between any of these 14 mutation/polymorphisms, major cardiovascular risk factors, and the absence of any flow-limiting stenosis, except for Factor V Leiden and hypertension (OR 6.34, 95% CI 2.67-100, P =.004).
Conclusions: Patients with no flow-limiting stenosis after MI had increased frequencies of 2 inherited thrombophilias (Factor V Leiden and beta-fibrinogen 448 A allele), and there was a trend toward an increased frequency of prothrombin variant G20210A compared with patients with > or =1 stenosis. These data suggest that polymorphisms/mutations in some gene products influencing coagulation may influence the pathogenesis of MI.