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LMWH Improves Post-STEMI Outcomes

Is there a role for low-molecular-weight heparin in the management of ST-segment-elevation myocardial infarction?

Is there a role for low-molecular-weight heparin (LMWH) in the management of ST-segment-elevation MI (STEMI)? To find out, researchers conducted a double-blind, placebo-controlled trial in which 15,570 STEMI patients in India and China (mean age, 59) were randomized to receive either the LMWH reviparin (dose-adjusted for body weight) or placebo for 1 week, in addition to usual post-STEMI care. All subjects presented within 12 hours of symptom onset, 73% underwent thrombolysis, and 6% underwent primary PCI. Reviparin's manufacturer provided the study drug.

Incidence of the primary composite endpoint (death, reinfarction, or stroke) was significantly lower among reviparin recipients than among placebo recipients at 7 days (9.6% vs. 11.0%) and at 30 days (11.8% vs. 13.6%). Reviparin's advantage was evident in rates of both death and reinfarction; stroke rates were similar in the reviparin and placebo groups.

The earlier reviparin treatment was initiated, the greater its benefits. For example, relative risk reductions at 30 days were 30% greater with reviparin than with placebo when treatment was initiated within <2 hours after symptom onset, 20% greater when initiated within 2 to 4 hours, 15% greater when initiated within 4 to <8 hours, and no greater when initiated 8 hours after onset.

At 7 days, life-threatening bleeding was more common with reviparin than with placebo (0.2% vs. 0.1%), but the absolute difference was small (17 vs. 7 events), especially when compared with the benefits in preventing death and reinfarction.

Comment: In this well-designed, randomized trial, the LMWH reviparin was associated with reductions in risk for mortality and reinfarction, without increasing the risk for stroke. However, because clinical practices (including PCI rates) in India and China differ from those in the U.S. and Europe, outcomes might have been different had the trial been conducted elsewhere. Still, as an editorialist notes, the overall case for LMWH over unfractionated heparin (UFH) is enhanced by the present findings in STEMI patients, by the lower cost and ease of administering LMWHs in a broad range of acute coronary syndromes, and by previous findings such as those from the ASSENT-3 trial, in which STEMI patients who received full-dose tenecteplase had significantly better outcomes with the LMWH enoxaparin than with UFH (Journal Watch Cardiology Nov 9 2001). It's unclear whether reviparin, which is not approved for marketing in the U.S., is more effective than enoxaparin and other LMWHs.

— JoAnne M. Foody, MD

Published in Journal Watch Cardiology March 18, 2005

Citation(s):

The CREATE Trial Group Investigators. Effects of reviparin, a low-molecular-weight heparin, on mortality, reinfarction, and strokes in patients with acute myocardial infarction presenting with ST-segment elevation. JAMA 2005 Jan 26; 293:427-35.

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• Medline abstract (Free)

Califf RM. Simple principles of clinical trials remain powerful. JAMA 2005 Jan 26; 293:489-91.

• Original article (Subscription may be required)
• Medline abstract (Free)