Lower cardiac index levels relate To lower cerebral blood flow in older adults

Angela L. Jefferson, Dandan Liu, Deepak K. Gupta, Imberly R. Pechman, Jennifer M. Watchmaker, Elizabeth A. Gordon, Swati Rane, Susan P. Bell, Lisa A. Mendes, L. Taylor Davis, Katherine A. Gifford, Timothy J. Hohman, Thomas J. Wang, Manus J. Donahue

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Objective: To assess cross-sectionally whether lower cardiac index relates to lower resting cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) among older adults. Methods: Vanderbilt Memory and Aging Project participants free of stroke, dementia, and heart failure were studied (n = 314, age 73 ± 7 years, 59% male, 39% with mild cognitive impairment). Cardiac index (liters per minute per meter squared) was quantified from echocardiography. Resting CBF (milliliters per 100 grams per minute) and hypercapnia-induced CVR were quantified from pseudo-continuous arterial spin-labeling MRI. Linear regressions with ordinary least-square estimates related cardiac index to regional CBF, with adjustment for age, education, race/ethnicity, Framingham Stroke Risk Profile score (systolic blood pressure, antihypertensive medication use, diabetes mellitus, current cigarette smoking, left ventricular hypertrophy, prevalent cardiovascular disease [CVD], atrial fibrillation), APOE ϵ4 status, cognitive diagnosis, and regional tissue volume. Results: Lower cardiac index corresponded to lower resting CBF in the left (β = 2.4, p = 0.001) and right (β = 2.5, p = 0.001) temporal lobes. Results were similar when participants with prevalent CVD and atrial fibrillation were excluded (left temporal lobe β = 2.3, p = 0.003; right temporal lobe β = 2.5, p = 0.003). Cardiac index was unrelated to CBF in other regions assessed (p > 0.25) and CVR in all regions (p > 0.05). In secondary cardiac index × cognitive diagnosis interaction models, cardiac index and CBF associations were present only in cognitively normal participants and affected a majority of regions assessed with effects strongest in the left (p < 0.0001) and right (p < 0.0001) temporal lobes. Conclusions: Among older adults without stroke, dementia, or heart failure, systemic blood flow correlates with cerebral CBF in the temporal lobe, independently of prevalent CVD, but not CVR.

Original languageEnglish (US)
Pages (from-to)2327-2334
Number of pages8
JournalNeurology
Volume89
Issue number23
DOIs
StatePublished - Dec 2017
Externally publishedYes

ASJC Scopus subject areas

  • Clinical Neurology

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