Safety and effectiveness of enoxaparin following fibrinolytic therapy: Results of the Acute Myocardial Infarction (AMI)-QUEBEC registry.

Background: Previous randomized controlled trials and meta-analyses demonstrated the superior efficacy of enoxaparin (ENOX) over unfractionated heparin (UFH) in patients with ST segment elevation myocardial infarction (STEMI). The external validity of randomized controlled trials may be limited by selective inclusion of patients who are younger and healthier than the 'real-life' population.

Objective: To evaluate the safety and effectiveness of ENOX compared with UFH in unselected STEMI patients.

Methods: The safety and effectiveness of ENOX and UFH were compared in STEMI patients who received fibrinolytic therapy at 17 Quebec hospitals in 2003.

Results: A total of 498 STEMI patients received systemic anticoagulation, with ENOX and UFH administered in 114 and 384 patients, respectively. There were no differences in baseline characteristics between the two patient groups. The rates of in-hospital major adverse cardiac or cerebral events were 11.4% in the ENOX group compared with 14.0% in the UFH group (P=0.51). In-hospital death or nonfatal reinfarction occurred in 7.9% of patients who received ENOX compared with 9.9% of patients who received UFH (P=0.52). Major bleeding occurred in 4.4% of patients who received ENOX versus 6.0% in patients who received UFH (P=0.51).

Interpretation: There was no significant difference in the rates of in-hospital adverse events in the ENOX group compared with the UFH group, when used in the real-life context. Larger observational studies may further confirm the safety, effectiveness and optimal duration of the administration of ENOX in unselected STEMI patients treated with fibrinolysis.