Antithrombotics in the Prevention of Reocclusion In Coronary Thrombolysis - APRICOT
APRICOT was an angiographic study that compared aspirin vs coumadin for the prevention of reocclusion and recurrent ischemia after successful thrombolysis.
The placebo reocclusion rate, assumed to be 30%, would be reduced by 40% to a rate of 18% in either active treatment arm.
Patients Enrolled: 284
Mean Follow Up: 3 months
Mean Patient Age: not reported
Mean Ejection Fraction: Baseline ejection fraction was 49% in the aspirin group, 52% in the coumadin group, and 51% in the placebo group.
Patients who present with chest pain <4 hours and >30 minutes duration and a minimum of 0.2 mV ST segment elevation in 2 contiguous ECG leads suggestive of acute MI; Patent infarct-related artery on the 48 hour catheterization.
Age >70 years; History of coronary surgery; Patients already on antithrombotic therapy or with a contraindication to antithrombotics; Patients with normal coronary arteries, significant left main stenosis, or an occluded infarct-related coronary artery.
Patency of the infarct-related artery at the 3 month follow-up angiography.
Incidence of recurrent myocardial infarction; incidence coronary surgery or angioplasty; change in left ventricular ejection fraction; combination of clinical course free of reinfarction, revascularization, or death; combination of clinical course free of reinfarction, revascularization, or death and a patent vessel at follow-up angiography.
Following angiography at 48 hours after thrombolytic administration, patients were randomized to one of the following: continuation of IV heparin and start of open label coumadin; discontinuation of IV heparin and treatment with 325 mg aspirin; discontinuation of IV heparin and treatment with placebo (double blind).
All patients received streptokinase (1.5 million U over 30-60 minutes) or APSAC (30 U over 5 minutes) and IV heparin (20,000 U/24 h with downward titration when aPTT >2.5 times the control value).
Reocclusion rates were not significantly different in the 3 treament arms (25% with aspirin, 30% with coumadin, and 32% with placebo; p=NS). Reinfarction was significantly lower in patients in the aspirin arm compared with placebo (3% vs 11%, p<0.025) but did not differ significantly from the coumadin arm (8%, p=NS). Mortality did not differ between groups (2% for each group). The revascularization rate was 6% with aspirin, 13% with coumadin, and 16% with placebo (aspirin vs placebo, p<0.05; other comparisons, p=NS). An event-free clinical course occurred more frequently among patients in the aspirin arm (93%) than in the coumadin arm (82%, p<0.05) or the placebo arm (76%, p<0.001). An event-free course without reocclusion was observed in 73% with aspirin, 63% with coumadin, and 59% with placebo (p=NS). An increase in left ventricular ejection fraction was seen in the aspirin group (4.6%, p<0.001) but not in the coumadin or placebo groups.
Compared with placebo, aspirin significantly reduces the reinfarction and revascularization rates, improves event-free survival, and better preserves left ventricular function. The efficacy of coumadin on these end points was less than that of aspirin. Despited these benefits, a high reocclusion rate remained, emphasizing the need for better antithrombotic therapy. As a result of this trial, the APRICOT-2 trial was designed to compared the 3 month angiographic rate of reocclusion rates in patients treated with aspirin alone to patients treated with a combination of coumadin and aspirin.
Keywords: Platelet Aggregation Inhibitors, Ventricular Function, Left, Warfarin, Heparin, Disease-Free Survival, Coronary Disease, Fibrinolytic Agents, Streptokinase, Chest Pain, Catheterization, Stroke Volume, Anistreplase
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