Assessment of the treatment effect of enoxaparin for unstable angina/non-Q-wave myocardial infarction - TIMI 11B-ESSENCE meta-analysis

Background-Two phase III trials of enoxaparin for unstable angina/non-Q-wav e myocardial infarction have shown it to be superior to unfractionated hepa rin for preventing a composite of death and cardiac ischemic events. A pros pectively planned meta-analysis was performed to provide a more precise est imate of the effects of enoxaparin on multiple end points. Methods and Results-Event rates for death, the composite end points of deat h/nonfatal myocardial infarction and death/nonfatal myocardial infarction/u rgent revascularization, and major hemorrhage were extracted from the TIMI 11B and ESSENCE databases. Treatment effects at days 2, 8, 14, and 43 were expressed as the OR (and 95% CI) for enoxaparin versus unfractionated hepar in, All heterogeneity tests for efficacy end points were negative, which su ggests comparability of the findings in TIMI 11B and ESSENCE. Enoxaparin wa s associated with a 20% reduction in death and serious cardiac ischemic eve nts that appeared within the first few days of treatment, and this benefit was sustained through 43 days. Enoxaparin's treatment benefit was not assoc iated with an increase in major hemorrhage during the acute phase of therap y, but there was an increase in the rate of minor hemorrhage, Conclusions-The accumulated evidence, coupled with the simplicity of subcut aneous administration and elimination of the need for anticoagulation monit oring, indicates that enoxaparin should be considered as a replacement for unfractionated heparin as the antithrombin for the acute phase of managemen t of patients with high-risk unstable angina/non-Q-wave myocardial infarcti on.