Assessment of the metabolic heart-brain axis with cardiac and brain ¹⁸F-FDG PET/CT imaging in patients with heart failure

Objectives: In this study, we aimed to evaluate the cerebral metabolism in patients with heart failure (HF) to determine the correlation between myocardial phenotypic characterization and cerebral metabolic activity.

Methods: Eighty-three HF patients were prospectively enrolled. All participants underwent gated ^99mTc-sestamibi single photon emission computed tomography (SPECT)/CT myocardial perfusion imaging, also cardiac and cerebral ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT. Fifteen healthy volunteers underwent cerebral FDG PET/CT imaging served as controls. Patients were stratified by extent of hibernating myocardium (HM) and left ventricular ejection fraction (LVEF) into 3 subgroups, group1: HM < 10% (n = 33); group2: HM ≥ 10%, LVEF < 25% (n = 34); group3: HM ≥ 10%, 25% ≤ LVEF ≤ 40% (n = 16). Cerebral metabolism expressed as the standardized uptake value (SUV) in the whole brain (SUV_whole-brain) and the SUV ratios (SUVR) corrected by cerebellar activity in 24 cognition related brain regions were determined. The relationship between cardiac imaging features and brain metabolism was assessed. Differences in brain metabolism between 3 subgroups of the patients and healthy volunteers were compared.

Results: The SUV_whole-brain (r = 0.28, P < 0.05) and SUVRs in frontal areas, hippocampus and para-hippocampus (range of r value: 0.23 to 0.40, all P < 0.05) was associated with the extent of HM. Whole brain metabolic uptake (SUV_whole-brain)in group 1 was significantly lower than that in healthy volunteers, whereas not differ among three patients-groups (P > 0.05). In comparison to volunteers, SUVRs (frontal areas) in group 3 were relatively elevated, whereas SUVRs (hippocampus and para-hippocampus) in group1 were significantly reduced (P < 0.05). SUVRs (frontal areas) in group 1 were significantly lower than group3 (P < 0.05).

Conclusions: The global and regional brain metabolic activity was significantly associated with the extent of HM and cardiac function in HF patients. The findings of this study might contribute to the physiopathological interpretation of cognitive impairment in patients with HF.