Overview of randomized trials of intravenous heparin in patients with acute myocardial infarction treated with thrombolytic therapy

Unfractionated and Low-Molecular-Weight Heparin as Adjuncts to Thrombolysis in Aspirin-Treated Patients With ST-Elevation Acute Myocardial Infarction

“…Other analyses restricted to patients who received intravenous UFH demonstrated no clear benefit of intravenous UFH. 8,64 No large-scale trials of intravenous UFH have been conducted in patients with STEMI, and it seems very unlikely that they will be performed in the future given the emergence of LMWH, which is not only more effective but is much less likely to cause heparin-induced thrombocytopenia and in most patients can be administered in a fixed-weight adjusted dose without laboratory monitoring. Exceptions include patients undergoing invasive procedures and those with renal impairment because the anticoagulant effect of LMWH cannot be reversed and accumulates in patients with reduced creatinine clearance.…”

“…Intravenous UFH is commonly recommended in those patients treated with a fibrin-specific thrombolytic agent or at high risk of systemic emboli 5,6 but has not been shown in individual trials to reduce reinfarction or death and may increase bleeding. [7][8][9][10] A recently completed large phase 3 trial demonstrated that LMWH (reviparin) reduces reinfarction and death, 11 but it is unclear from direct randomized comparisons whether LMWH is superior to UFH. 12,13 To further clarify the efficacy and safety of UFH and LMWH for the treatment of STEMI, we performed a metaanalysis of randomized trials comparing UFH or LMWH with untreated control (no heparin) or placebo or comparing UFH with LMWH in patients routinely treated with aspirin and a thrombolytic agent.…”

Aspirin Plus Coumarin Versus Aspirin Alone in the Prevention of Reocclusion After Fibrinolysis for Acute Myocardial Infarction

“…5,15 With it, the routine use of subcutaneous UFH only conferred a modest additional clinical benefit, which was lost early after discharge. 16,17 The limited data regarding adjunctive intravenous UFH do not suggest an important clinical benefit 17,18 despite a suggested beneficial effect on patency and reocclusion in different settings. With conventional administration of 3 to 6 hours of r-TPA, adjunctive intravenous UFH did not result in higher 90-minute patency, 19 yet an effect on 7-to 120-hour patency has been demonstrated.…”

Thrombolysis in Myocardial Infarction

“…Hsia J et al(1990) have shown that thrombolysis achieves faster lysis with greater vessel patency in combination with heparin (between 7 and 24 hours a patent vessel was found in 88% of those receiveing thrombolysis with heparin and aspirin vs. 52% in those treated with thrombolysis and aspirin alone). Unfortunately this does not translate into clinical outcome with a meta-analysis of the six trials by Muhaffey KW et al (1996) showing that there were similar rates of mortality and re-infarction before discharge. Despite this the general consensus from expert opinion is that heparin is beneficial in preventing re-occlusion and that it should be given as a bolus with all thrombolytics other than Streptokinase and then be given as a continuous IV infusion.…”