Low molecular weight heparin decreases rebound ischemia in unstable angina or non-Q-wave myocardial infarction: the Canadian ESSENCE ST segment monitoring substudy

• Published in: Journal of the American College of Cardiology Vol. 36; no. 5; pp. 1507 - 1513
• Main Authors: Goodman, Shaun G, Barr, Aiala, Sobtchouk, Anatoli, Cohen, Marc, Fromell, Gregg J, Laperrière, Luc, Hill, Carol, Langer, Anatoly
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.11.2000; Elsevier Science
• Subjects: Aged; Angina, Unstable - complications; Angina, Unstable - mortality; Angina, Unstable - physiopathology; Biological and medical sciences; Blood. Blood coagulation. Reticuloendothelial system; Electrocardiography; Enoxaparin - therapeutic use; Female; Fibrinolytic Agents - therapeutic use; Follow-Up Studies; Humans; Male; Medical sciences; Middle Aged; Myocardial Infarction - complications; Myocardial Infarction - mortality; Myocardial Infarction - physiopathology; Myocardial Ischemia - etiology; Myocardial Ischemia - mortality; Myocardial Ischemia - prevention & control; Pharmacology. Drug treatments; Recurrence; Survival Rate; Time Factors; Canada; North America; America; LMWH; ESSENCE; OR; CI; UFH; ECG; MI; Human; Prognosis; Infarct; ST interval; Cardiovascular disease; Low molecular weight heparin; Anticoagulant; Coronary heart disease; Myocardial disease; Survival; Enoxaparin sodium; Chemotherapy; Treatment; Follow up study; Myocardium; Variant angina
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/S0735-1097(00)00915-3

OBJECTIVES The goal of this study was to determine whether enoxaparin was more effective than heparin in reducing recurrent ischemic episodes. BACKGROUND Continuous ST segment monitoring is a simple tool for assessment of ischemia and identifies patients with a worse prognosis. Little is known about the impact of low molecular weight heparin on ST segment shift. METHODS Patients were randomized to receive enoxaparin or heparin (mean 3.4 days). Three-lead ST segment monitoring was performed for the first 48 h (n = 220) and an additional 48 h (n = 174) after intravenous study drug discontinuation (mean 1.9 days later). RESULTS During initial monitoring, ischemia rates were similar among the heparin and enoxaparin groups (27.2% vs. 22.6%, p = 0.44); however, the time to first ischemic episode was earlier among heparin-treated patients (11 ± 11 vs. 25 ± 18 min, p = 0.001). After drug discontinuation, ischemic episodes occurred more frequently (44.6% vs. 25.6%, p = 0.009), and the total ischemic duration was greater among heparin patients (18 ± 39 vs. 5 ± 12 min/24 h, p = 0.005). Recurrent ischemia occurred more frequently after discontinuation in the heparin (46% vs. 31%, p = 0.043), but not the enoxaparin, group (18.4% vs. 25%, p = 0.33). Regardless of treatment, patients with ischemia were more likely to die or experience (re)infarction at one year (18.4% vs. 8.3%, p = 0.023). CONCLUSIONS ST segment shift occurs frequently in unstable angina/non-Q-wave myocardial infarction despite antithrombotic therapy and is associated with worse one-year prognosis. Enoxaparin is a more effective antithrombotic treatment than unfractionated heparin and leads to greater prevention of rebound ischemia.