Randomized Comparison of Enoxaparin, a Low-Molecular-Weight Heparin, With Unfractionated Heparin Adjunctive to Recombinant Tissue Plasminogen Activator Thrombolysis and Aspirin: Second Trial of Heparin and Aspirin Reperfusion Therapy - HART II
The second trial of Heparin and Aspirin Reperfusion Therapy (HART II) was a randomized comparison of enoxaparin, a low-molecular-weight heparin, with unfractionated heparin (UFH) adjunctive to recombinant tissue plasminogen activator thrombolysis and aspirin.
Is low-molecular-weight heparin (enoxaparin) as effective and safe as UFH as an adjunctive therapy during thrombolytic treatment for acute myocardial infarction (AMI)?
Patients Enrolled: 400
Patients undergoing reperfusion therapy with an accelerated recombinant tissue plasminogen activator regimen and aspirin (n=400) for AMI were randomly assigned to receive adjunctive therapy for at least three days with either enoxaparin or UFH. Noninferiority of enoxaparin versus UFH with regard to infarct-related artery patency was the study endpoint.
Patency rates at 90 minutes (thrombolysis in myocardial infarction [TIMI] flow grade 2 or 3) were 80.1% and 75.1% in the enoxaparin and UFH groups, respectively. Similarly, TIMI grade 3 flow at 90 minutes was more frequent in the enoxaparin group versus the UFH group (52.9% vs. 47.6%).
Reocclusion at 5-7 days from TIMI grade 2 or 3 to TIMI 0 or 1 flow and TIMI grade 3 to TIMI 0 or 1 flow, respectively, occurred in 5.9% and 3.1% of the enoxaparin group versus 9.8% and 9.1% in the UFH group. Adverse events (bleeding and 30-day mortality) occurred with similar frequency in both treatment groups.
Enoxaparin is at least as effective as UFH as an adjunct to thrombolysis, with a trend toward higher 90-minute infarct artery patency rates and less reocclusion at 5-7 days.
The results of this study complement the findings of the more recently published and much larger ASSENT-3 trial (Lancet 2001;358:605-13), suggesting superior efficacy and similar safety of enoxaparin as an adjunct to thrombolysis as compared to UFH. The simplicity of administration and monitoring should make enoxaparin an attractive choice as an adjunct to thrombolysis.
Ross AM, Molhoek P, Lundergan C, et al. Randomized comparison of enoxaparin, a low-molecular-weight heparin, with unfractionated heparin adjunctive to recombinant tissue plasminogen activator thrombolysis and aspirin: second trial of Heparin and Aspirin Reperfusion Therapy (HART II). Circulation 2001;104:648-52.
Keywords: Myocardial Infarction, Enoxaparin, Heparin, Low-Molecular-Weight, Heparin, Fibrinolytic Agents, Tissue Plasminogen Activator
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