Efficacy and safety of enoxaparin in unselected patients with ST-segment elevation myocardial infarction

In randomized clinical trials the low-molecular-weight heparin enoxaparin has been shown to reduce ischemic complications in patients with acute ST elevation myocardial infarction (STEMI) treated with fibrinolysis. Little is known about the use and efficacy of enoxaparin in unselected patients with STEMI in clinical practice. In a retrospective analysis of the prospective ACOS registry we compared the outcomes of patients with STEMI treated with enoxaparin or unfractionated heparin. A total of 6,299 patients with STEMI < 12 hours were included in this analysis, 609 (10%) were treated with enoxaparin and 5,690 (90%) with unfractionated heparin. In the multivariable propensity score analysis enoxaparin was associated with a reduction in the combined endpoint of death and non-fatal reinfarction in the entire group (odds ratio 0.59; 95% CI 0.43-0.80) and the subgroups of patients treated without early reperfusion (odds ratio 0.65, 95% CI 0.43-0.97), fibrinolysis (odds ratio 0.64; 95% CI 0.33-1.26) and primary percutaneous coronary intervention (odds ratio 0.33; 95% CI 0.15-0.72). There was no significant increase in severe bleeding complications with enoxaparin (6.5% versus 5.5%, p = 0.4). In clinical practice in unselected patients with STEMI treated with or without early reperfusion therapy early treatment with enoxaparin compared to unfractionated heparin is associated with a significant reduction of the combined endpoint of inhospital death and reinfarction without a significant increase in severe bleeding complications.