¹⁸ F-FDG PET/CT brain glucose metabolism as a marker of different types of depression comorbidity in chronic heart failure patients with impaired systolic function

Aims: Depression is an important issue in heart failure (HF). The study investigated whole-brain and regional brain glucose metabolism in HF patients and its association with depression comorbidity.

Methods and results: Twenty-nine hospitalized patients with symptomatic systolic HF (left ventricular ejection fraction <40%), New York Heart Association (NYHA) class II-IV and mean age of 55.5 ± 12.0 years, had psychometric questionnaires before discharge and an ¹⁸ F-FDG PET/CT brain scan after discharge. Semi-automated image analysis was performed on all cases and 30 matched controls. The metabolic parameter mean standardized uptake value (SUV_mean ) was calculated for the whole brain and three brain regions implicated in depression pathogenesis. A standardized SUV_mean was also estimated by dividing regional brain SUV_mean with whole-brain SUV_mean . Cases had lower average whole-brain SUV_mean (3.90 ± 1.49 vs. 5.10 ± 1.35, P = 0.001) and average regional brain SUV_mean (4.57 ± 2.31 vs. 9.96 ± 3.58, P < 0.001) compared to controls. Whole-brain SUV_mean had a significant correlation with patient age, NYHA class, diabetes, creatinine levels, depression, and cognitive impairment. Regional brain SUV_mean was correlated with whole-brain SUV_mean and depression. The standardized SUV_mean , in particular, was found to be a robust index that could differentiate HF patients with 'epiphenomenal' (>0.93) or 'real' (≤0.93) depression.

Conclusion: Heart failure patients with more severe disease showed whole-brain and regional brain hypometabolism in ¹⁸ F-FDG PET/CT. Depressed HF patients (Beck Depression Inventory score >13) exhibited different metabolic patterns that could be used to differentiate between 'epiphenomenal' and 'real' depression. Namely, presence of whole-brain hypometabolism suggested 'epiphenomenal' depression, whereas absence suggested 'real' depression. Presence of significant relative regional brain hypometabolism enhanced the likelihood of 'real' depression diagnosis.