Prediction of functional outcome by quantification of sestamibi and BMIPP after acute myocardial infarction

Iodine-123 15-(p-iodaphenyl)-3-R,S-methyl-pentadecanoic acid (BMIPP) can be used to image myocardial fatty acid regional distribution and utilisation with single-photon emission tomography (SPET). By visual analysis, a mismat ching with regional uptake of BMIPP less than that of a perfusion tracer ha s been shown to predict myocardial viability and functional improvement aft er restoration of flow in patients with myocardial infarction. The current study aimed to evaluate a newly developed quantitative method of analysis o f ses tamibi and BMIPP uptake for the prediction of functional recovery aft er revascularization in patients with acute infarction. BMIPP and Sated ses tamibi SPET studies at rest were obtained before and >3 months after revasc ularization in 18 patients with recent infarction. A colour-coded polar map was generated from the comparison of sestamibi and BMIPP uptake. Depending on the relative distribution of the two tracers, different patterns of upt ake were identified and their extent expressed as percentages of the surfac e of the whole left ventricle and of the three main coronary artery territo ries. At follow-up, recovery was defined as a greater than or equal to 5% i ncrease in election fraction compared with baseline. Receiver-operating cha racteristic curve analysis was performed to analyse the data. At baseline, significant correlations were found between ejection fraction and the % sur face with decreased ses tamibi or BMIPP uptake (r=-0.68, P= 0.001, and r=-0 .72, P<0.0001, respectively). When combining both tracers, ejection fractio n was significantly associated with the extent of myocardium showing decrea sed sestamibi uptake with lower BMIPP uptake (mismatching; r=-0.68, P=0.001 ), At follow-up, significant functional recovery was found in 13/18 patient s. By ROC curve analysis, the optimal pattern of distribution predicting re covery was a mismatching with uptake of sestamibi <70% and uptake of BMIPP at least 10% lower. For this parameter, optimal cut-off of extent was 10% o f the whole left ventricle surface (sensitivity 69%, specificity 80%, accur acy 72%) and 25% of the infarct-related arterial territory (sensitivity 77% , specificity 80%, accuracy 78%). The areas under the curve were 79% for th e left ventricle surface and 72% for the individual arterial territories. T hese results suggest that in patients with acute infarction, quantitative a nalysis of sestamibi and BMIPP could offer an objective and reproducible me thod for estimating the severity of cardiac dysfunction and predicting the evolution of ejection fraction after revascularization.