In aspirin-treated STEMI patients receiving thrombolysis, LMWH compared with UFH reduced reinfarction (3.0% vs 5.2%; OR 0.57; 95% CI 0.45-0.73; NNT=45).
Meta-Analysis (n=25,280)
Randomized
Does unfractionated heparin or low-molecular-weight heparin reduce reinfarction and death in aspirin-treated patients with STEMI receiving thrombolysis?
In STEMI patients treated with aspirin and thrombolysis, LMWH is superior to placebo and UFH for reducing reinfarction and death, though it increases the risk of major and intracranial bleeding.
Odds Ratio: 0.57 (95% CI 0.45–0.73)
Absolute Event Rate: 3% vs 5.2%
Number Needed to Treat: 45
BACKGROUND: There is uncertainty about the role of intravenous unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) in patients with ST-elevation myocardial infarction (STEMI) treated with aspirin and thrombolysis. METHODS AND RESULTS: We performed a meta-analysis of the randomized trials to assess the effect of UFH and LMWH on reinfarction, death, stroke, and bleeding. Fourteen trials involving a total of 25,280 patients were included (1239 comparing intravenous UFH versus placebo or no heparin; 16,943 comparing LMWH versus placebo; and 7098 comparing LMWH versus intravenous UFH). Intravenous UFH during hospitalization did not reduce reinfarction (3.5% versus 3.3%; odds ratio OR, 1.08; 95% CI, 0.58 to 1.99) or death (4.8% versus 4.6%; OR, 1.04; 95% CI, 0.62 to 1.78) and did not increase major bleeding (4.2% versus 3.4%; OR, 1.21; 95% CI, 0.67 to 2.18) but increased minor bleeding (19.6% versus 12.5%; OR, 1.72; 95% CI, 1.22 to 2.43). During hospitalization/at 7 days, LMWH compared with placebo reduced the risk of reinfarction by approximately one quarter (1.6% versus 2.2%; OR, 0.72; 95% CI, 0.58 to 0.90; number needed to treat NNT=167) and death by OR, 0.90; 95% CI, 0.80 to 0.99; NNT=111) but increased major bleeding (1.1% versus 0.4%; OR, 2.70; 95% CI, 1.83 to 3.99; number needed to harm NNH=143) and intracranial bleeding (0.3% versus 0.1%; OR, 2.18; 95% CI, 1.07 to 4.52; NNH=500). The reduction in death with LMWH remained evident at 30 days. LMWH compared with UFH during hospitalization/at 7 days reduced reinfarction by OR, 0.57; 95% CI, 0.45 to 0.73; NNT=45), did not reduce death (4.8% versus 5.3%; OR, 0.92; 95% CI, 0.74 to 1.13) or increase major bleeding (3.3% versus 2.5%; OR, 1.30; 95% CI, 0.98 to 1.72), but increased minor bleeding (22.8% vs 19.4%; OR, 1.26; 95% CI, 1.12 to 1.43). The reduction in reinfarction remained evident at 30 days. CONCLUSIONS: In aspirin-treated patients with STEMI who are treated with thrombolysis, intravenous UFH has not been shown to prevent reinfarction or death. LMWH given for 4 to 8 days compared with placebo reduces reinfarction by approximately one quarter and death by &10% and when directly compared with UFH reduces reinfarction by almost one half. These data suggest that LMWH should be the preferred antithrombin in this setting.
Eikelboom et al. (Tue,) conducted a meta-analysis in ST-elevation acute myocardial infarction (STEMI) (n=25,280). Low-molecular-weight heparin (LMWH) vs. Intravenous unfractionated heparin (UFH) was evaluated on Reinfarction (OR 0.57, 95% CI 0.45 to 0.73). In aspirin-treated STEMI patients receiving thrombolysis, LMWH compared with UFH reduced reinfarction (3.0% vs 5.2%; OR 0.57; 95% CI 0.45-0.73; NNT=45).