Key points are not available for this paper at this time.
Revascularization with primary percutaneous coronary intervention for ST segment elevation myocardial infarction results in restored epicardial flow in the majority of patients. However, in more than 25% of patients, flow does not translate into tissue perfusion. To assess revascularization success, it is necessary to evaluate beyond epicardial flow and to address tissue perfusion. 99mTc-sestamibi single photon emission computed tomography (SPECT) might be useful in this setting, but whether sestamibi redistributes when administered during reperfusion has been debated. The aim of this study was to investigate whether clinically significant redistribution could be detected in a porcine model mimicking acute myocardial infarction and revascularization. Ten pigs were studied in a closed-chest model of myocardial infarction. 99mTc-sestamibi was administered during reperfusion, and SPECT was performed every 30 min for 4 h. The quantitative program CEQUAL was used for analysis and perfusion defects were reported in percentage. All animals had eight acquisitions. The size of the perfusion defect in the individual animals ranged from (mean +/- SD) 13 +/- 3 to 34 +/- 2%. The difference between the first and the last perfusion defect in a single animal was (mean +/- SD) 2.5 +/- 5.3%, which is not statistically significant (P = 0.17). The slopes of regression lines obtained from plots of the individual values ranged from -1.39 to 0.76 with a mean of -0.23 +/- 0.68, which is not statistically significant (P = 0.31). In conclusion, we found no sign of sestamibi redistribution in this experimental set-up of reperfused myocardial infarction. If these findings can be extrapolated to clinical practice, then it means that acquisition can be performed at any time within the first 4 h after tracer injection without significant difference in perfusion assessment.
Kaltoft et al. (Thu,) studied this question.