Factor V Leiden and the Risk of Bleeding in Patients With Acute Coronary Syndromes Treated With Antiplatelet Therapy: Pooled Analysis of 3 Randomized Clinical Trials.

Background Whether factor V Leiden is associated with lower bleeding risk in patients with acute coronary syndromes using (dual) antiplatelet therapy has yet to be investigated. Methods and Results We pooled data from 3 randomized clinical trials, conducted in patients with acute coronary syndromes, with adjudicated bleeding outcomes. Cox regression models were used to obtain overall and cause-specific hazard ratios (HRs) to account for competing risk of atherothrombotic outcomes (ie, composite of ischemic stroke, myocardial infarction, and cardiovascular death) in each study. Estimates from the individual studies were pooled using fixed effect meta-analysis. The 3 studies combined included 17 623 patients of whom 969 (5.5%) were either heterozygous or homozygous (n=23) carriers of factor V Leiden. During 1 year of follow-up, a total of 1289 (7.3%) patients developed major (n=559) or minor bleeding. Factor V Leiden was associated with a lower risk of combined major and minor bleeding (adjusted cause-specific HR, 0.75; 95% CI, 0.56-1.00; P=0.046; I2=0%) but a comparable risk of major bleeding (adjusted cause-specific HR, 0.93; 95% CI, 0.62-1.39; P=0.73; I2=0%). Adjusted pooled cause-specific HRs for the association of factor V Leiden with atherothrombotic events alone and in combination with bleeding events were 0.75 (95% CI, 0.55-1.02; P=0.06; I2=0%) and 0.75 (95% CI, 0.61-0.92; P=0.007; I2=0%), respectively. Conclusions Given that the lower risk of bleeding conferred by factor V Leiden was not counterbalanced by a higher risk of atherothrombotic events, these findings warrant future assessment for personalized medicine such as selecting patients for extended or intensive antiplatelet therapy.