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 reoc clusion after successful thrombolysis and to analyze the influence of three antithrombotic treatment regimens. Background. After successful thrombolysis, reocclusion is a major problem. Prediction of reocclusio n by angiographic data and choice of antithrombotic treatment would be important for clinical management. Methods. After thrombolysis, patie nts were treated with intravenous heparin until initial angiography wa s performed within 48 h. Patients with a patent infarct-related artery were eligible. Three hundred patients were randomly selected for trea tment with coumadin, aspirin (300 mg once daily) or placebo. Patency o n a second angiographic study after 3 months was the primary end point of the study. Results. Reocclusion rate was 25% with aspirin, 30% wit h coumadin and 32% with placebo (p=NS). Lesions with >90% stenosis reo ccluded more frequently (42%) than did those with <90% stenosis (23%) (p<0.01). Reocclusion rate of smooth lesions was higher (34%) than tha t of complex lesions (23%) (p<0.05). In lesions with <90% stenosis, th e 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% t o be an independent predictor of reocclusion (odds ratio 2.31, 95% con fidence interval 1.28 to 4.18, p=0.006). Conclusions. Angiographic fea tures of the culprit lesion after successful coronary thrombolysis sig nificantly 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 inv estigation of the effects of an aggressive approach to patients with s evere residual stenosis.