Delayed recovery of myocardial perfusion after successful coronary angioplasty of infarct-related artery in patients with prior myocardial infarction.

Abstract

We studied the status of myocardial perfusion before and after coronary angioplasty (PTCA) of infarct-related artery using stress thallium scan in patients with prior myocardial infarction. Twenty-six patients who had anterior myocardial infarction caused by single-vessel disease at the left anterior descending coronary artery were involved. Patients were classified into the following four groups according to the stress-redistribution thallium scintigraphic findings before PTCA: complete redistribution (two cases), incomplete redistribution (12 cases), partial redistribution (seven cases) and no redistribution (five cases). In the group with complete redistribution, the extent of residual ischaemia in the infarct area decreased significantly after PTCA but infarct size only slightly. In the groups with incomplete and partial redistribution, the extent of residual ischaemia and infarct size decreased significantly after PTCA. In contrast, the group with no redistribution showed a slight decrease in the extent of residual ischaemia and a gradual decrease in infarct size beginning 3 months after PTCA. Clinical findings including electrocardiogram indicated that the patients with incomplete redistribution had more viable myocardium and the patients with no redistribution had more scarring. The groups with incomplete and partial redistribution showed characteristics intermediate between complete and no redistribution. The change of infarct area after PTCA was different between the four groups, but both residual ischaemia and infarct size decreased in all groups. Thus, PTCA of the infarct-related coronary artery is useful even in the patients with prior myocardial infarction, even in patients with no redistribution shown by stress thallium scan.