P2260Impacts of hippocampal blood flow on cardiac remodeling in patients with chronic heart failure
Authors: Suzuki H , Matsumoto Y , Sugimura K , Takahashi J , Miyata S , Fukumoto Y , Arai H , Taki Y , Shimokawa H 
Published: October 2019

Abstract

Background
Chronic heart failure (CHF) patients have a high prevalence of depression. Increased mortality and hospitalization are noted in depressive CHF patients. We have previously demonstrated that cerebral blood flow in the hippocampus, which is the important brain area for emotion and memory, is associated with depressive symptoms in CHF patients (Brain Assessment and Investigation in Heart Failure Trial (B-HeFT), UMINehz748.073808584).

Purpose
To test our hypothesis that blood flow in the hippocampus (green areas, Figure A, B) is associated with cardiac remodeling in CHF patients.

Methods
We enrolled 80 CHF patients aged 45–90 years from August 2012 to April 2013. We measured hippocampal blood flow, psychological test scores, and echocardiographic parameters as baseline values within 6 months after enrollment. Among them, echocardiography was repeated in 70 patients (65.0±10.0 [SD] yrs, 71.4% men) at 3.1±0.5 years after the baseline evaluation in B-HeFT2 (UMINehz748.073820355). Hippocampal blood flow was measured with pseudocontinuous arterial spin labeling perfusion images acquired with a 1.5-T whole-body MRI system. The patients underwent the 15-item Geriatric Depression Scale (GDS) test, where existence of depressive symptoms was defined as 5 or more in the GDS score. To test our hypothesis, we conducted a voxel-wise multiple regression analysis, using blood flow at each voxel in the hippocampus as independent variable and differences in echocardiographic parameters between the 2 time points as dependent variable adjusted for age and sex.

Results
Consistent with our hypothesis, baseline blood flow in the hippocampus was significantly associated with the changes in left-ventricular posterior wall thickness (LVPWT). Anterior hippocampal blood flow was negatively correlated with changes in LVPWT (blue areas, Figure A, B), while positive correlations of posterior hippocampal blood flow were found (red areas, Figure A, B) (P<0.05 uncorrected for multiple comparisons). The negative correlations in limited areas of the anterior hippocampus survived at a significance threshold of P<0.05 with family-wise error corrections (yellow areas, Figure A, B). A correlation coefficient between baseline anterior hippocampal blood flow and changes in LVPWT was –0.452 (P<0.001, Figure C). Existence of depressive symptoms was positively correlated with baseline anterior hippocampal blood flow and negatively with changes in LVPWT (P<0.05, both). A structural equation model showed that, apart from a direct effect [standardized estimate 0.344 (95% CI 0.564, 0.124), P=0.002], the association between baseline anterior hippocampal blood flow and LVPWT thinning was mediated by existence of depressive symptoms [standardized estimate 0.111 (95% CI 0.213, 0.002), P=0.046] (Figure D).
Figure 1

Conclusions
These results provide the first evidence that hippocampal blood flow is associated with cardiac remodeling, which is mediated, at least partly, by existence of depressive symptoms.

Acknowledgement/Funding
Japan Society for the Promotion of Science