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)

Background-Adjunctive unfractionated heparin (UFH) during thrombolytic ther apy for acute myocardial infarction (AMI) promotes the speed and magnitude of coronary artery recanalization and reduces reocclusion. Low-molecular-we ight heparins offer practical and potential pharmacological advantages over UFH in multiple applications but have not been systematically studied as a djuncts to fibrinolysis in AML Methods and Results-Four hundred patients undergoing reperfusion therapy wi th an accelerated recombinant tissue plasminogen activator regimen and aspi rin for AMI were randomly assigned to receive adjunctive therapy for at lea st 3 days with either enoxaparin or UFH. The study was designed to show non inferiority of enoxaparin versus UFH with regard to infarct-related artery patency. Ninety minutes after starting therapy, patency rates (thrombolysis in myocardial infarction [TIMI] flow grade 2 or 3) were 80.1% and 75.1% in the enoxaparin and UFH groups, respectively. Reocclusion at 5 to 7 days fr om TIMI grade 2 or 3 to TIMI 0 or 1 flow and TIMI grade 3 to TIMI 0 or I fl ow, respectively, occurred in 5.9% and 3.1% of the enoxaparin group versus 9.8% and 9.117c in the UFH group. Adverse events occurred with similar freq uency in both treatment groups. Conclusions-Enoxaparin was at least as effective as UFH as an adjunct to th rombolysis, with a trend toward higher recanalization rates and less reoccl usion at 5 to 7 days.