A critical review of the efficacy and safety in the use of low-molecular-weight heparin in acute ST-elevation myocardial infarction: a Bayesan approach.

BACKGROUND: ST segment elevation myocardial infarction (STEMI) is an important risk factor of death worldwide. Significant clinical research has been done to assess ideal reperfusion strategies in the setting of STEMI, including the role of the antithrombin agents: unfractionated heparin (UFH) and low molecular weight heparin (LMWH). Given the evidence that LMWH may be safer than UFH in the treatment of other thrombotic disorders, its role in the management of STEMI needs to be more defined. OBJECTIVE: To assess the safety and efficacy of LMWH compared to UFH and/or placebo for the treatment of STEMI. MATERIALS AND METHODS: The Cochrane Library, MedLine and EMABASE databases were searched for randomized controlled trials pertinent to the study objective. Selection criteria included all randomized controlled trials comparing LMWH to either UFH or placebo in the treatment of STEMI through December 2010. Two Authors performed the search independently.After identifying appropriate studies, a random effect model and Bayesian sensitivity analysis were used to combine results from original trials and assess the consistency of results. RESULTS: We identified 13 studies that met the described selection criteria; 8 comparing LMWH to UFH and 5 to placebo in STEMI patients. The combined Odd's ratio was 0.79 with a 95% confidence interval of 0.67-0.94 for all studies and 0.74 (0.54-1.02) for those comparing LMWH to UFH only. A trend toward more frequent hemorrhagic events was identified in the LMWH group (Odd's ratio 1.40) which did not meet statistical significance (95% confidence interval 0.80-2.47). Sensitivity analysis demonstrated clinical benefits of 6% and 12.5% with probabilities of 99% and 95% respectively. CONCLUSION: Compared to placebo or UFH, LMWH is effective as a first line treatment of STEMI patient with no significant increase in major hemorrhagic events.