Subcutaneous enoxaparin following thrombolysis and intravenous unfractionated heparin in ST-elevation acute myocardial infarction: safety and efficacy of low vs full dose.
OBJECTIVE
In ST-segment elevation myocardial infarction (STEMI) treated with fibrin-specific thrombolytic agents, early intravenous unfractionated heparin (UFH) is warranted. Low molecular weight heparin Enoxaparin currently represents an alternative to UFH, to be used until hospital discharge. Since optimal dosing of subcutaneous Enoxaparin is not standardized, we conducted an observational study to compare safety and efficacy of low (4,000 U once daily) vs full dose (100 U/kg twice daily) regimens.


METHODS
All STEMI patients successfully treated with tenecteplase and intravenous UFH and referred to the Catheterization Laboratory between June 2002-November 2003 for predischarge coronary angiography, were evaluated. The primary end-point was the composite of hemorrhages and residual angina/reinfarction during Enoxaparin administration, whereas secondary end-points were occurrence of venous thromboembolism (VTE) during Enoxaparin administration, and infarct-related artery (IRA) patency rate at predischarge coronary angiography.


RESULTS
Out of 123 patients, 57 (M/F 45/12, mean age 65.8+/-8.1 years) received low dose, and 66 (men/women 45/21, mean age 62.6+/-11.8 years) full dose subcutaneous Enoxaparin. The incidence of the composite primary end-point was comparable in both groups (19% vs 26%; P=NS). Also, null was the occurrence of VTE, whereas the IRA patency rate did not significantly differ in the 2 groups (84% vs 86% TIMI 3 and 11% vs 9% TIMI 2 flow grades; P=NS).


CONCLUSIONS
In patients with STEMI undergoing successful recanalization with tenecteplase and intravenous UFH, low dose subcutaneous Enoxaparin appears preferable to full dose, in the light of comparable safety and clinical efficacy and superior easiness of use.
Division of Cardiology, Ospedale Maggiore, Bologna, Italy. andrearubboli@libero.it
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Rubboli
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Gatti
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Spinolo
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Parollo
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Spitali
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Maresta
D000368:Aged; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D017984:Enoxaparin / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D006329:Heart Conduction System / Q000503:physiopathology*; D006493:Heparin / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D007275:Injections, Intravenous; D007279:Injections, Subcutaneous; D007558:Italy; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D011446:Prospective Studies; D000077785:Tenecteplase; D015912:Thrombolytic Therapy; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*; D016896:Treatment Outcome
D017984:Enoxaparin; D005343:Fibrinolytic Agents; D006493:Heparin; D010959:Tissue Plasminogen Activator; D000077785:Tenecteplase