"Enoxaparin versus Unfractionated Heparin in Unstable Coronary Artery Disease". The New England Journal of Medicine. 1997. 337(7):447-452. PubMed•Full
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Contents 1 Clinical Question 2 Bottom Line 3 Major Points 4 Guidelines 5 Design 6 Population 6.1 Inclusion Criteria 6.2 Exclusion Criteria 6.3 Baseline Characteristics 7 Interventions 8 Outcomes 8.1 Primary Outcome 8.2 Secondary Outcomes 9 Criticisms 10 Funding 11 Further Reading
In patients with unstable coronary artery disease (angina or non–Q-wave myocardial infarction), is low-molecular-weight heparin (enoxaparin) more effective than standard unfractionated heparin in combination with aspirin in reducing ischemic events?
In patients with unstable angina or non–Q-wave myocardial infarction, enoxaparin plus aspirin was more effective than unfractionated heparin plus aspirin in reducing the incidence of ischemic events at 14 and 30 days, without a significant increase in major bleeding.
Unfractionated heparin therapy has a notable failure rate in unstable coronary artery disease due to its unpredictable anticoagulant response and potential for rebound events after discontinuation. Low-molecular-weight heparin (LMWH) offers several advantages, such as predictable anticoagulant effect, ease of administration, and resistance to activated platelet inhibition, making it a promising alternative.
As of the last knowledge update, specific guidelines reflecting the direct comparison of LMWH and unfractionated heparin in unstable coronary artery disease were not detailed, and further studies may contribute to guideline recommendations.
- Prospective, randomized, double-blind, placebo-controlled, multicenter trial. - N=3,171 patients with unstable angina or non–Q-wave myocardial infarction. - Setting: 176 hospitals in 10 countries. - Enrolled from October 1994 to May 1996. - Analysis: Intention-to-treat. - Primary outcome: Composite of death, myocardial infarction (reinfarction), or recurrent angina at 14 days.
Inclusion Criteria - Recent angina at rest or non–Q-wave myocardial infarction within 24 hours before randomization. - Evidence of underlying ischemic heart disease. - Age at least 18 years.
Exclusion Criteria - Left bundle-branch block, persistent ST-segment elevation, angina with established precipitating cause, contraindications to anticoagulation, creatinine clearance rate <30 ml per minute.
Baseline Characteristics - Similar across treatment groups.
- Enoxaparin (LMWH) 1 mg/kg subcutaneously every 12 hours or continuous intravenous unfractionated heparin. - Adjusted according to activated partial-thromboplastin time. - Therapy duration: Minimum of 48 hours to a maximum of 8 days. - All patients received 100–325 mg of oral aspirin daily.
Primary Outcome - Composite of death, myocardial infarction, or recurrent angina at 14 days: 16.6% in enoxaparin group vs. 19.8% in unfractionated heparin group (P=0.019).
- Composite of death, myocardial infarction, or recurrent angina at 30 days: 19.8% enoxaparin vs. 23.3% unfractionated heparin (P=0.016). - Need for revascularization at 30 days: 27.0% enoxaparin vs. 32.2% unfractionated heparin (P=0.001). - Incidence of major bleeding: 6.5% enoxaparin vs. 7.0% unfractionated heparin. - Incidence of bleeding overall: 18.4% enoxaparin vs. 14.2% unfractionated heparin (P=0.001), primarily due to ecchymoses at injection sites.
- The occurrence of minor bleeding was significantly higher in the enoxaparin group, mainly due to injection-site ecchymosis. - Superiority of enoxaparin might be influenced by the challenges in achieving the therapeutic range with unfractionated heparin.
The study was supported by the Rhône-Poulenc Rorer Corporation.
The full text provides a comprehensive understanding of the study, including details on the study's design, statistical analysis, and implications for clinical practice.