Congestive heart failure and its associations with cognition and cerebral blood flow.

Background: Congestive heart failure (CHF) has been linked to dementia but for reasons not well understood. Our retrospective cohort study aims to determine if specific measures of CHF severity are associated with cognitive performance or cerebral blood flow velocity (CBFV) among decompensated CHF outpatients.

Materials and methods: One hundred and thirty-eight patients with transthoracic echocardiogram ≤1-year preceding consent were included. Forty-nine patients had concurrent transcranial Doppler ultrasonography administered by a trained technician assessing anterior cerebral artery, middle cerebral artery, and internal carotid artery (ICA) CBFV. CHF characteristics considered were NYHA classification, CHF type (heart failure with preserved ejection fraction vs. heart failure with mildly reduced/reduced ejection fraction), and left ventricular ejection fraction (LVEF; continuous [per 5%] or categorized [≤40%, 40%-55%, and ≥55%]). A trained psychometrist administered a standardized cognitive battery including Rey Auditory Verbal Learning Test, Rey Complex Figure Copy and Immediate Recall test, Letter-Number Sequencing (LNS) test, and Trail Making Tests. Adjusted multivariable linear regression models determined the association between CHF characteristics and standardized cognitive tests as well as between CHF characteristics and standardized CBFV, in distinct models.

Results: On average, NYHA Class 1-2 patients had better LNS scores than NYHA Class 3-4 patients (β: 0.47; 95% CI: 0.09, 0.84). Patients with LVEF 40%-55% had higher ICA CBFVs than those with LVEF ≤40% (β: 13.7; 95% CI: 1.01, 26.39). No associations between other CHF characteristics and either cognitive performance or CBFV were found.

Conclusion: Blood flow may be an important mechanism behind CHF-related cognitive decline, but studies with larger sample sizes and a control group without CHF are needed.