Are regions of ischaemia detected on stress perfusion scintigraphy predictive of sites of subsequent myocardial infarction?

To determine the relation between scintigraphic regions of stress-induced ischaemia and subsequent myocardial infarction, a select group of 21 patients was investigated. Each patient had undergone stress perfusion scintigraphy before myocardial infarction was recorded. After acute infarction, thallium-201 perfusion scintigraphy was performed in 16 patients (76%) and 99mTc (stannous) pyrophosphate in 14 patients (67%). All patients had at least one post-myocardial infarction scintigram and nine (42%) had both perfusion scintigraphy and infarct imaging. Nineteen patients (90%) had scintigraphic evidence of stress-induced ischaemia pre-infarction. Scintigraphic regions of infarction were compared with regions of previously demonstrated stress-induced ischaemia. In 11 patients (53%) the myocardial infarction was more extensive; in one of these patients, reimaged one week before myocardial infarction, and in four others (19%) there were matching defects; in three patients (14%) the infarction was less extensive, and in two patients (9%) the infarction was less extensive but also involved regions not previously shown to develop ischaemia. In the final patient (5%) there was no match. Stress perfusion scintigraphy was generally abnormal before acute infarction in this group of patients. Acute infarction frequently involved regions previously shown to develop stress-induced ischaemia, though these often underestimated the extent of myocardium at risk.