Abstract 3299: Efficacy and Safety of Enoxaparin vs. UFH in Patients with ST-Elevation Myocardial Infarction Also Treated Or Not Treated with Clopidogrel: Analysis from ExTRACT-TIMI 25
Background: Compared to unfractionated heparin (UFH), enoxaparin (ENOX) reduced death or MI in patients with STEMI undergoing fibrinolysis in ExTRACT-TIMI 25. Randomized trials have also shown that clopidogrel reduces death and MI in STEMI. Whether the benefit and safety profiles seen with ENOX are comparable in patients who are and are not treated with clopidogrel remains incompletely defined.
Methods: We compared the rates of death/MI, TIMI major bleeding, and ICH in pts randomized to ENOX vs. UFH stratified by whether pts did (n=1663) or did not (n=13,736) receive clopidogrel at the discretion of their treating physician. The analysis was restricted to pts receiving clopidogrel only for medical therapy for STEMI by excluding those who underwent PCI after initial fibrinolysis.
Results: ENOX reduced the risk of death or MI (Figure⇓) both in patients treated with clopidogrel (RR 0.61, 95% CI 0.38–0.99) and in patients not treated with clopidogrel (OR 0.86, 95% CI 0.78–0.94), with no evidence of significant heterogeneity (Pint=0.32). Similarly, the absolute risk difference (ARD) in TIMI major bleeding (Table) seen with ENOX as compared to UFH was comparable in those who were (ARD with ENOX 1.1%) vs. those who were not (0.7%) treated with clopidogrel (Pint=NS). There was no significant different in ICH with ENOX vs. UFH, and this was regardless of clopidogrel therapy (Pint=NS).
Conclusion: In patients with STEMI undergoing fibrinolysis, ENOX significantly reduces death or MI and is as safe both in patients who are and are not treated with clopidogrel. A combination of a fibrinolytic, aspirin, clopidogrel, and enoxaparin may be the optimal pharmacologic reperfusion strategy for STEMI.