Impacts of hippocampal blood flow on changes in left ventricular wall thickness in patients with chronic heart failure

Background: Although depressive symptoms increased mortality and hospitalization in chronic heart failure (CHF) patients, the underlying mechanism remains unclear. The aim of this study was to investigate whether an alteration in hippocampal perfusion, which is the neural substrate of depressive symptoms, is associated with changes in cardiac structures and/or functions in CHF patients. Methods: We used baseline data of 70 CHF patients (66.8 ± 8.9 yrs, 32.5% women), including cerebral blood flow (CBF) in the hippocampus, geriatric depression scale (GDS) scores and echocardiographic parameters, in the Brain Assessment and Investigation in Heart Failure Trial (B-HeFT) (UMIN000008584). Echocardiography was repeated at 3.1 ± 0.5 years after the baseline evaluation. We first tested voxel-wise regression model with hippocampal CBF as dependent variable and each of echocardiographic parameter change as independent variable, adjusted for age and sex. Structural equation modeling was used to test a mediation effect of cognitive test scores on associations between hippocampal perfusion and changes in cardiac structures and/or functions. Results: Baseline anterior hippocampal CBF was negatively correlated with changes in left ventricular posterior wall thickness (PWT) (P < 0.05 with family-wise error corrections). An existence of depressive symptoms was positively correlated with the baseline anterior CBF and negatively with the PWT changes (P < 0.05, both). There were both direct effects of the baseline anterior hippocampal CBF on PWT thinning and effects mediated through the depressive symptoms (P < 0.05, both). Conclusions: This study provides the first evidence that the alteration in hippocampal perfusion may lead to changes in cardiac structures via increase in depressive symptoms in CHF patients.