[Usefulness of coronary angioplasty (PTCA) of the infarct-related artery in patients with prior myocardial infarction--follow up of infarct zone pre- and post-angioplasty by stress thallium scan].

We studied the efficacy of coronary angioplasty (PTCA) of the infarct-related artery in 29 patients with prior myocardial infarction by stress thallium scan. Twenty-seven patients had anterior myocardial infarction (single LAD disease), one had inferior (single RCA disease) and one had posterior (single LCX disease). According to the stress-redistribution thallium scintigraphic finding before PTCA, the patients were classified in 4 groups; (A): three patients with complete redistribution. (B): fourteen patients with incomplete redistribution. (C): seven patients with partial redistribution. (D): five patients with no redistribution. After PTCA, the parameters of residual ischemia in the infarct area (% RD and Thallium ischemic score = TIS) were improved significantly but those of infarct size (RD% uptake and Defect Score = DS) were improved slightly in group A. In group B and C, % RD, TIS, RD% uptake and DS were all improved significantly. In group D, TIS was improved slightly and DS was improved slowly 3 months after PTCA. Group A had high probability of viable muscle and group D had high probability of scar at the infarct zone. Group B and C showed intermediate type between group A and D. The change of infarct area after PTCA was variable in 4 groups but both residual ischemia and infarct size decreased in all groups. Thus, PTCA of infarct-related coronary artery is useful even in the patients with prior myocardial infarction.