Aspirin and Coumadin after Acute Coronary Syndromes (The ASPECT-2) Study: A Randomised Controlled Trial. - ASPECT-2
What is the relative efficacy of high dose warfarin (target INR 3-4) and a combination of warfarin (target INR 2-2.5) with low dose aspirin compared to low dose aspirin in long term secondary prevention after acute coronary events?
Patients Enrolled: 999
Patients admitted for acute coronary events (999) at 53 sites were randomised in an open-label fashion to low-dose aspirin (n=336), high-intensity oral anticoagulation (n=325), or combined low-dose aspirin and moderate intensity oral anticoagulation (n=332) and followed up for a maximum of 26 months. The primary composite endpoint was first occurrence of myocardial infarction, stroke, or death.
The primary endpoint (composite of first occurrence of myocardial infarction, stroke and death) occurred 9% of patients on aspirin, in 5% of those on anticoagulants (hazard ratio 0.55 [95% CI 0.30-1.00], p=0.0479), and in 5% of the cohort on combination therapy (0.50 [0.27-0.92], p=0.03). Major bleeding was similar in all three groups (<2%), while minor bleeding was increased in the combination therapy (5% vs. 15%, 3.13 [1.82-5.37], p=<0.0001). Patients in the two coumadin arms were more likely to permanently discontinue the study drug. Analyses were done by intention to treat.
High-intensity oral anticoagulants or aspirin with medium-intensity oral anticoagulants is more effective than aspirin alone in reducing subsequent cardiovascular events and death in patients admitted with acute coronary events. While the close monitoring of patients in clinical trial setting allows better anticoagulation and accounts for the lower major bleeding rates (<2% in the current study), the difficulty in achieving such tight control and close follow-up in day to day practice is well known. Thus, although this trial suggests the superiority of high-intensity anticoagulation and moderate intensity anticoagulation in combination with low dose aspirin over aspirin alone, coumadin therapy may be best reserved for patients with other indications for such therapy (atrial fibrillation, documented left atrial or ventricular clots, mechanical prosthetic valves etc).
Keywords: International Normalized Ratio, Myocardial Infarction, Stroke, Follow-Up Studies, Secondary Prevention, Warfarin, Atrial Fibrillation, Hemorrhage
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