Factor V Leiden Does Not Modify the Phenotype of Acute Coronary Syndrome or the Extent of Myocardial Necrosis.

Background The prothrombotic defect factor V Leiden (FVL) may confer higher risk of ST-segment-elevation myocardial infarction (STEMI), compared with non-ST-segment-elevation acute coronary syndrome, and may be associated with more myocardial necrosis caused by higher thrombotic burden. Methods and Results Patients without history of cardiovascular disease were selected from 2 clinical trials conducted in patients with acute coronary syndrome. FVL was defined as G-to-A substitution at nucleotide 1691 in the factor V (factor V R506Q) gene. Odds ratios were calculated for the association of FVL with STEMI adjusted for age and sex in the overall population and in the subgroups including sex, age (≥70 versus <70 years), and traditional cardiovascular risk factors. The peak biomarker levels (ie, creatine kinase-myocardial band and high-sensitivity troponin I or T) after STEMI were contrasted between FVL carriers and noncarriers. Because of differences in troponin assays, peak high-sensitivity troponin levels were converted to a ratio scale. The prevalence of FVL mutation was comparable in patients with STEMI (6.0%) and non-ST-segment-elevation acute coronary syndrome (5.8%). The corresponding sex- and age-adjusted odds ratio was 1.06 (95% CI, 0.86-1.30;