Randomized trial of low molecular weight heparin (enoxaparin) versus unfractionated heparin for unstable coronary artery disease: one-year results of the ESSENCE Study. Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q Wave Coronary Events.

OBJECTIVES: We sought to determine whether the observed benefits of enoxaparin were maintained beyond the early phase; a one-year follow-up survey was undertaken for patients enrolled in the Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q wave Coronary Events (ESSENCE) study.

BACKGROUND: We have previously reported a significant benefit of low molecular weight as compared with unfractionated heparin (UFH) in the 14- and 30-day incidence of a composite end point of death, myocardial infarction (MI) or recurrent angina in patients with unstable angina or non-Qwave MI.

METHODS: The study recruited 3,171 patients with recent-onset rest angina and underlying ischemic heart disease. All patients received oral aspirin daily and were randomized to receive enoxaparin subcutaneously every 12 h or UFH (intravenous bolus followed by continuous infusion) in a double-blind, double-dummy fashion for a median of 2.6 days.

RESULTS: The incidence of the composite triple end point at one year was lower among patients receiving enoxaparin as compared with those receiving UFH (32.0% vs. 35.7%, p = 0.022), with a trend toward a lower incidence of the secondary composite end point of death or MI (11.5% vs. 13.5%, p = 0.082). At one year, the need for diagnostic catheterization and coronary revascularization was lower in the enoxaparin group (55.8% vs. 59.4%, p = 0.036 and 35.9% vs. 41.2%, p = 0.002, respectively).

CONCLUSIONS: In patients with unstable angina or non-Qwave MI, enoxaparin therapy significantly reduced the rates of recurrent ischemic events and invasive diagnostic and therapeutic procedures in the short term with sustained benefit at one year.