Residual area at risk after anterior myocardial infarction: Are ST segment changes during coronary angioplasty a reliable indicator? A comparison with technetium 99m-labeled sestamibi single-photon emission computed tomography

Abstract

Background. The aim of this study was to assess whether, after anterior myocardial infarction, ST segment changes during percutaneous transluminal coronary angioplasty (PTCA) of the left anterior descending coronary artery correlated with the amount of ischemic myocardium in the area at risk, measured with 99mTc-labeled sestamibi single-photon emission computed tomography (SPECT) during balloon inflation. Methods and Results. Quantitative continuous monitoring of the ST segment was performed during PTCA of the left anterior descending coronary artery in 11 patients, and corresponding SPECT imaging was compared with a rest acquisition performed before PTCA. SPECT was quantified by a bull's-eye analysis according to main criteria: (1) the planimetered defect size during PTCA as an indicator of the size of the area at risk, (2) the change in the pathologic/normal area count ratio in the area at risk as an index of the severity of ischemia, and (3) the difference between the size of the defect during PTCA and at baseline. ST segment changes were correlated to the variation in pathologic/normal area count ratio (19% ± 14%; r = 0.61; p < 0.05) but not to the sizes of the scintigraphic defects. Conclusion. ST segment changes induced by occlusion of the infarct-related coronary artery during PTCA are related mostly to the severity of ischemia rather than to the size of the area at risk.