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

Neurology. 2017 Dec 5;89(23):2327-2334. doi: 10.1212/WNL.0000000000004707. Epub 2017 Nov 8.


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 & 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.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Apolipoprotein E4 / genetics
  • Brain / diagnostic imaging
  • Cardiac Output / physiology*
  • Cardiovascular Diseases / physiopathology
  • Cerebrovascular Circulation / physiology*
  • Cognitive Dysfunction / complications
  • Cohort Studies
  • Cross-Sectional Studies
  • Electrocardiography
  • Female
  • Humans
  • Longitudinal Studies
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Temporal Lobe / blood supply


  • Apolipoprotein E4