Abstract 2860: Does the Efficacy of the Low-Molecular Weight Heparin Enoxaparin over Unfractionated Heparin Balance the Safety Profile in ST-elevation Myocardial Infarction? A Meta-Analysis of 27,000 Patients
Background: We sought to determine whether the increased efficacy demonstrated in several trials with the low-molecular weight heparin enoxaparin (ENOX) over unfractionated heparin (UFH) remains favorable when incorporating the safety profile of these adjunctive therapies among patients with ST-elevation myocardial infarction (STEMI).
Methods: We performed a meta-analysis of randomized trials of ENOX vs UFH in STEMI patients treated with fibrinolytic therapy and aspirin (n=27,131 patients). The primary endpoint was net clinical benefit, defined as death by 30 days or in-hospital recurrent MI or major bleeding and was analyzed using a random effects model.
Results: The primary endpoint of death, MI or major bleeding occurred less frequently with ENOX compared with UFH (9.7% vs 11.7%, OR 0.82, 95% CI 0.71–0.94, p=0.006; Figure⇓). Among the individual endpoints, mortality at 30 days trended lower with ENOX (6.6% vs 7.1%, OR 0.92, 95% CI 0.84–1.01, p=0.097), in-hospital reinfarction was significantly lower with ENOX (2.2% vs 4.0%, OR 0.54, 95% CI 0.45–0.64, p<0.001), and in-hospital major bleeding was significantly higher with ENOX (2.1% vs 1.4%, OR 1.45, 95% CI 1.21–1.75, p<0.001). The reduction in death, MI or major bleeding was evident even when excluding individual trials in a sensitivity analysis.
Conclusions: When compared with UFH, ENOX offered superior net clinical benefit as adjunctive antithrombin therapy for fibrinolysis in STEMI. While bleeding was increased with ENOX, this increase was offset by a reduction in death or reinfarction.