[Dipyridamole-thallium 201 tomography following acute myocardial infarct: significance for stratifying cardiac risk factors].

For the purpose of risk stratification 80 consecutive patients (mean age 58 +/- 7) with a chest pain syndrome after documented myocardial infarction underwent tomographic vasodilation-redistribution thallium-201 perfusion imaging, using 0.56 mg/kg intravenous dipyridamole. Tomograms were analyzed for size and location of reversible and fixed perfusion defects and correlated to angiographic characteristics, left ventricular ejection fraction and wall motion, collateral status, and 1-year prognosis as measured by cardiac events within 14 +/- 3 months. No serious side effects were noted with the diagnostic use of intravenous dipyridamole. According to the perfusion pattern three subgroups of post-infarction patients were identified: 1) by ischemia at a distance with redistribution in non-infarct related territories (n = 48), 2) by peri-infarctional ischemia with redistribution in the territory of the "infarct artery" (n = 9), and 3) by exclusively fixed defects without redistribution (n = 23). Ischemia at a distance was associated with a larger reversible defect than peri-infarctional ischemia (p less than 0.05) and the pattern without redistribution (p less than 0.005); the fixed defect size, however, was similar in all three subgroups. In addition, the severity of coronary artery disease (Gensini score and number of diseased vessels) and the degree of collateralization was higher in presence of a redistribution pattern (p less than 0.05), although no significant differences in global and regional function were noted as a function of thallium-201 redistribution.(ABSTRACT TRUNCATED AT 250 WORDS)