Safety and efficacy of enoxaparin versus unfractionated heparins in conservatively managed patients with acute coronary syndrome: a systematic review

Aim:
Guidelines recommend initial anticoagulant management of acute coronary syndrome (ACS) with low molecular weight heparin (LMWH) such as enoxaparin or unfractionated heparin (UFH). Systematic reviews evaluate early trials in the context of multiple other medications or during percutaneous coronary intervention (PCI) only. We conducted an updated systematic review and meta-analysis focusing on the efficacy and safety of enoxaparin versus UFH in conservatively managed patients with ACS.

Data Sources:
Embase (Elsevier), the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, and MEDLINE (Ovid) were searched for randomised controlled trials (RCTs) from January 2002–February 2024 comparing enoxaparin to UFH treatment in patients with ACS, reporting 30-day all-cause mortality (efficacy), 30-day incidence of myocardial infarction (MI) (efficacy), and major bleeding events (safety). To account for heterogeneity, the random effects meta-analysis method of DerSimonian and Laird was used.

Study Selection:
Seven RCTs, with 12 197 patients were included where 6 177 (50.64%) patients received enoxaparin and 6 020 (49.36%) patients received UFH.

Results:
A risk reduction of 12% in MI with enoxaparin (risk ratio [RR] 0.88, 95% confidence interval [CI] 0.78–0.99, p = 0.04) compared with UFH. UFH showed a reduction in major bleeding at 30 days (RR 1.20, 95% CI 0.72–2.00, p = 0.48) and a reduction in mortality risk at 30 days (RR 1.14, 95% CI 0.94–1.39, p = 0.20).

Conclusion:
Overall, enoxaparin is more efficacious in reducing MI risk at 30 days. However, UFH showed reduction in major bleeding and mortality risk at 30 days. Further research in patients with different clinical conditions will provide a greater understanding of differences in efficacy and safety of enoxaparin versus UFH.