CORONARY LESION MORPHOLOGY IN ACUTE MYOCARDIAL-INFARCTION - DEMONSTRATION OF EARLY REMODELING AFTER STREPTOKINASE TREATMENT

Coronary lesion morphology was analyzed in 72 patients 1 to 8 days after streptokinase treatment for acute myocardial infarction and compared with lesion morphology in a control group of 24 patients with stable angina. In the streptokinase group the infarct-related artery was patent in 55 patients (76%). Compared with stenoses in the stable angina group, there were no differences in the stenosis length, severity, calcification or in the proportion located at an acute bend or at a branch point. However, lesions in the streptokinase group were more often irregular (p < 0.005) and eccentric (p < 0.01), had a shoulder (p < 0.0001), globular filling defects (p < 0.01), linear filling defects (p < 0.00005) and contrast staining (p < 0.05). Plaque ulceration index was higher in the streptokinase than in the stable angina group (6.2 ± 7.9 versus 3.5 ± 3.4, p < 0.001). Of the 72 streptokinase-treated patients, 35 were maintained on heparin infusion until angioplasty 2 to 10 days later. At repeat angiography before angioplasty, globular lesion filling defects seen in eight patients had disappeared, whereas linear filling defects persisted in 7 of 14 cases. Fewer lesions were irregular (p < 0.0001) and the ulceration index decreased from 7.4 ± 10.4 to 3.0 ± 1.6 (p < 0.001). These data show that the lesion in the infarct-related artery after streptokinase treatment is irregular and often associated with filling defects, perhaps corresponding to plaque fissuring and intraluminal thrombosis. These unstable features are partially resolved with maintenance heparin infusion and, because they are known to increase the risks of angioplasty, this procedure should be delayed whenever possible. © 1990.