ExTRACT-TIMI 25 trial: clarifying the role of enoxaparin in patients with ST-elevation myocardial infarction receiving fibrinolysis.

Pharmacologic reperfusion remains the most common treatment strategy for ST-elevation myocardial infarction (STEMI) worldwide. Unfractionated heparin (UFH) is the established adjunctive antithrombotic agent used with fibrinolytic agents. Low-molecular-weight heparins (LMWHs) are a potential alternative to UFH, but have not been evaluated in large cohorts of patients. The Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment (ExTRACT)-Thrombolysis in Myocardial Infarction (TIMI) 25 was a double-blind, double-dummy randomized controlled trial, of 20,479 patients, which demonstrated the superiority of enoxaparin over UFH in reducing death or nonfatal myocardial infarction (MI) at 30 days, with an increase in major bleeding. The composite of death, nonfatal MI and nonfatal intracranial hemorrhage, was reduced with enoxaparin. Elderly patients (> or = 75 years of age) received a novel enoxaparin dosing regimen and when compared with UFH, benefited from a lower relative bleeding risk than younger patients without compromising efficacy in preventing death or MI. Intracranial hemorrhage rates were similar. The net clinical benefit of enoxaparin over UFH was maintained regardless of whether patients were on clopidogrel or not, or whether percutaneous coronary intervention was performed. Enoxaparin is an appropriate choice for adjunctive therapy with fibrinolysis in patients with STEMI.