Early assessment of regional myocardial blood flow and metabolism in thrombolysis in myocardial infarction flow grade 3 reperfused myocardial infarction using carbon-11–acetate

OBJECTIVES The aim of this study was to investigate the prognostic value of carbon-11–acetate (acetate) positron emission tomography (PET) after successful reperfusion of myocardial infarction (MI). BACKGROUND Acetate PET allows the measurement of both myocardial flow and oxidative metabolism. The prognostic value of acetate measurements performed early (within 24 h) after Thrombolysis In Myocardial Infarction (TIMI) flow grade 3 reperfused MI is unknown. METHODS In 18 patients with TIMI flow grade 3 reperfusion of their first MI, a dynamic acetate study was performed within 24 h of the acute event. At five days, nitrogen-13–NH3 (NH3) and fluorine-18–labeled fluorodeoxyglucose (FDG) PET studies were performed. Infarct-related areas were classified as “PET viable” or “PET nonviable,” as assessed with NH3 and FDG, according to previously established criteria. At five days and three months, radionuclide angiography was performed for evaluation of left ventricular (LV) function. RESULTS In infarct-related regions, myocardial blood flow, FDG uptake and oxygen consumption were decreased, compared with remote regions. However, oxygen consumption values, as measured with acetate in both PET-viable and PET-nonviable areas, as assessed with NH3 and FDG, were not significantly different (p = NS). A significant linear correlation was observed between global LV ejection fraction at three months and oxidative metabolism in the infarct-related area (r = 0.8, p < 0.0001). Multivariate analysis revealed that oxidative metabolism measurements in reperfused myocardium was the only significant predictor for recovery of LV function at three months (p < 0.05). CONCLUSIONS Measurement of oxidative metabolism early after TIMI flow grade 3 reperfusion of MI offers important prognostic value concerning LV function at follow-up.