Prognostic Value of Dynamic FDG PET-Derived Myocardial Glucose Metabolism in Ischemic Cardiomyopathy with Supportive...

Background/Objectives: To evaluate whether global myocardial glucose metabolism and its regional heterogeneity, quantified using dynamic ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG PET), are associated with cardiovascular outcomes in patients with ischemic cardiomyopathy. Methods: The analytic cohort included 120 patients with suspected ischemic cardiomyopathy who underwent thallium-201 perfusion single photon emission tomography and dynamic FDG PET. Global myocardial metabolic rate of glucose (MRGlu) and coefficient of variation in FDG uptake were calculated from scar-excluded myocardium. Major adverse cardiac events (MACEs) were assessed over a median follow-up of 2.5 years. Public myocardial gene-expression datasets (GSE116250 and GSE135055) were analyzed to explore glucose metabolism-related transcriptional patterns relevant to the imaging findings. Results: Fifty-one patients (42.5%) experienced MACEs. Lower global MRGlu was independently associated with improved MACE-free survival (hazard ratio 0.48, 95% confidence interval 0.27-0.87). Among patients with low global MRGlu, a high coefficient of variation predicted favorable outcomes (hazard ratio 0.35, 95% confidence interval 0.18-0.68), indicating beneficial metabolic heterogeneity. Analysis of external gene-expression data demonstrated consistent downregulation of glucose-handling genes in end-stage heart failure across ischemic and dilated etiologies. A higher expression of SLC2A1, HK1, IRS1, and PKM was associated with faster progression to transplantation. Conclusions: In ischemic cardiomyopathy, dynamic FDG PET-derived quantification of myocardial glucose metabolism provides prognostic information beyond traditional viability assessment. Low global metabolism combined with preserved metabolic heterogeneity helps identify patients with favorable clinical outcomes.