Feasibility of an accurate assessment of myocardial salvage by comparing functional and perfusion abnormalities in post-reperfusion gated SPECT

Abstract

Background. Because of persistent stunning, post-treatment functional abnormalities could identify the initial risk area. The study aims to detect myocardial salvage using postrevascularization gated SPECT in acute myocardial infarction (AMI) treated by reperfusion therapy.Methods. In 36 AMI patients, we performed a first gated SPECT injecting 99mTc-sestamibi before primary percutaneous coronary intervention (PCI), and a second 5 days later. The salvage index defined by the two perfusion images was compared with the value obtained by subtracting in the second gated SPECT the extent of perfusion defect from the extent of wall thickening abnormalities.Results. The wall thickening salvage index correlated with the reference perfusion salvage index (Spearman's q 5 .92, P < .0001), with a 95% limit of agreement 5 ±.25. The agreement between the classifications in salvage index tertiles of the reference and of the wall thickening salvage index was good (kappa 5 .75). All patients with optimal PCI result and 18/24 of those with intermediate or poor outcome were correctly classified.Conclusions. Comparing function and perfusion in a single post-PCI 99m Tc-sestamibi gated SPECT it is possible to estimate myocardial salvage. This could have useful implications in studies comparing different treatment strategies for AMI. (J Nucl Cardiol 2010;17:825-30.)

Acute Myocardial Infarction: Estimation of At-Risk and Salvaged Myocardium at Myocardial Perfusion SPECT 1 Month after Infarction

“…This model resulted in a high concordance between myocardium atrisk area at the first gated SPECT examination and estimated myocardium at-risk area at the second examination. Automatic quantification of the extent of perfusion and wall motion abnormalities, which we performed in our study, is a more reproducible method than analysis of the discrepancy between perfusion and thickening assessed subjectively in an earlier phase of AMI (12), and this can partially explain why…”

“…To estimate the area of myocardium at risk using only variables from the second gated SPECT examination, we set up several models. (12). The best model, permitting the most correct estimate of the area of myocardium at risk, included AMI location, extent of the perfusion defect, and extent of the wall motion abnormality.…”

“…These results suggest that salvaged myocardium can potentially be measured by means of a simple delayed gated SPECT acquisition in place of the more difficult approach that depends on the acquisition of both acute and delayed perfusion images. In the study of Sciagrà et al (12), regional perfusion and wall thickening images were interpreted subjectively by a single observer. In contrast, a semiquantitative analysis was used to measure infarct size and salvaged myocardium in our study.…”

“…However, in the clinical setting, there is a logistic difficulty in performing early gated SPECT with injection of a radiotracer before PCI in patients with AMI. Consequently, some authors (11,12) have tried to estimate the extent of salvaged myocardium by using a myocardial perfusion gated SPECT study performed soon after an early PCI procedure for AMI. To our knowledge, Implication for Patient Care n SPECT imaging at 1 month allows estimation of the risk area at initial presentation; moreover, assessment of the risk area can be relevant for the clinical treatment of patients who did not previously undergo coronary angiography but who received thrombolytic therapy, because in these patients, estimation of salvaged myocardium represents an index of myocardium at risk in the event of a future coronary occlusion.…”

Measuring myocardium at risk in acute myocardial infarction—A continuing challenge

“…In this study imaging was performed at an average of 5 days with a range of 2-8 days. Previous work from our laboratory cited by Sciagra et al 17 indicated that measurement of infarct size at 48 hours would over-estimate infarct size in some patients. 18 Unfortunately, myocardial stunning has already started to resolve at that time in some patients.…”