CULPRIT LESION MORPHOLOGY AND STENOSIS SEVERITY IN THE PREDICTION OF REOCCLUSION AFTER CORONARY THROMBOLYSIS - ANGIOGRAPHIC RESULTS OF THE APRICOT STUDY

Objectives. In the APRICOT study (Antithrombotics in the Prevention of Reocclusion In Coronary Thrombolysis), we sought to determine whether angiographic characteristics of the culprit lesion could predict reocclusion after successful thrombolysis and to analyze the influence of three antithrombotic treatment regimens. Background. After successful thrombolysis, reocclusion is a major problem. Prediction of reocclusion by angiographic data and choice of antithrombotic treatment would be important for clinical management. Methods. After thrombolysis, patients were treated with intravenous heparin until initial angiography was performed within 48 h. Patients with a patent infarct-related artery were eligible. Three hundred patients were randomly selected for treatment with coumadin, aspirin (300 mg once daily) or placebo. Patency on a second angiographic study after 3 months was the primary end point of the study. Results. Reocclusion rate was 25% with aspirin, 30% with coumadin and 32% with placebo (p=NS). Lesions with >90% stenosis reoccluded more frequently (42%) than did those with <90% stenosis (23%) (p<0.01). Reocclusion rate of smooth lesions was higher (34%) than that of complex lesions (23%) (p<0.05). In lesions with <90% stenosis, the reocclusion rate was lower with aspirin (17%) than with coumadin (25%) or placebo (30%) (p<0.01). In complex lesions, the reocclusion rate was lower with aspirin (14%) than with coumadin (32%) or placebo (25%) (p<0.02). Multivariate analysis showed only stenosis severity >90% to be an independent predictor of reocclusion (odds ratio 2.31, 95% confidence interval 1.28 to 4.18, p=0.006). Conclusions. Angiographic features of the culprit lesion after successful coronary thrombolysis significantly predict the risk of reocclusion: high grade (>90%) stenoses reoccluded more frequently. Aspirin was effective only in complex and less severe lesions (<90% stenosis). These findings should prompt investigation of the effects of an aggressive approach to patients with severe residual stenosis.