Prothrombotic Single Nucleotide Polymorphisms and Risk of Myocardial Infarction: A Narrative Review of the Literature

Background: Environmental risk factors for myocardial infarction (MI) have been extensively investigated. In addition, family history of MI is an important risk factor for the disease. Several prothrombotic genotypes are well-established risk factors for venous thrombosis. However, the role of prothrombotic genotypes as risk factors for arterial thrombosis is less emphasized. Aim: To create a general overview of the existing literature on the role of non-O/O blood type, Prothrombin G20210A and Factor V Leiden; the main genetic determinants of thrombophilia, as risk factors for incident MI. Methods: A narrative literature review of studies published after 2005 was performed. The biomedical databases Medline and Embase were used in a structured literature search regarding the association between non-O/O blood type, Prothrombin G20210A and Factor V Leiden as risk factors for MI. Relevant MeSH terms for exposure and outcome were combined in the Ovid search platform; a common search software for the two databases. Results: Several meta-analyses have been published during the recent years and report modest effects of non-O blood type (ORs ranging from 1.1 to 1.3), Prothrombin G20210A (ORs around 1.4) and Factor V Leiden (ORs ranging from 1.2 to 1.9) on the risk of MI. For Prothrombin G20210A, the adjusted OR for ST-elevation myocardial infarction (STEMI) for carriers versus non-carriers of the risk allele was 2.2 (95% CI: 1.1-4.3) among subjects <35 years. Moreover, when compared to wild genotype carriers, Factor V Leiden heterozygous or homozygous mutant carriers were more likely associated with a trend towards more severe coronary artery disease (CAD) (OR 1.85; 95% CI 1.26-2.72 and OR 3.70; 95% CI 1.71-8.00). Conclusion: In conclusion, the existing literature supports an association between non-O blood type, Prothrombin G20210A and Factor V Leiden and risk of MI. The Prothrombin G20210A and Factor V Leiden variants seem to be associated with premature adverse events and more severe CAD.