Steady-state cerebral autoregulation in older adults with amnestic mild cognitive impairment: Linear mixed model analysis

Li Zhang, Evan P. Pasha, Jie Liu, Chang Yang Xing, Danilo Cardim, Takashi Tarumi, Kyle Womack, Linda S. Hynan, C. Munro Cullum, Rong Zhang

Research output: Contribution to journalArticlepeer-review

Abstract

We examined whether the efficacy of steady-state cerebral autoregulation (CA) is reduced in older adults with amnestic mild cognitive impairment (aMCI), a prodromal stage of clinical Alzheimer disease (AD). Forty-two patients with aMCI and 24 cognitively normal older adults (NC) of similar age, sex, and education underwent stepwise decreases and increases in mean arterial pressure (MAP) induced by intravenous infusion of sodium nitroprusside and phenylephrine, respectively. Changes in cerebral blood flow (CBF) were measured repeatedly in the internal carotid and vertebral artery. Linear mixed modeling, including random effects of both individual intercept and regression slope, was used to quantify the MAP-CBF relationship accounting for nonindependent, repeated CBF measures. Changes in end-tidal CO2 (EtCO2) associated with changes in MAP were also included in the model to account for their effects on CBF. Marginal mean values of MAP were reduced by 13-14 mmHg during sodium nitroprusside and increased by 20-24 mmHg during phenylephrine infusion in both groups with similar doses of drug infusion. A steeper slope of changes in CBF in response to changes in MAP was observed in aMCI relative to NC, indicating reduced efficacy of CA (MAP × Group, P = 0.040). These findings suggest that cerebrovascular dysfunction may occur early in the development of AD.

Original languageEnglish (US)
Pages (from-to)377-385
Number of pages9
JournalJournal of applied physiology
Volume129
Issue number2
DOIs
StatePublished - Aug 2020

Keywords

  • Alzheimer disease
  • Cerebral autoregulation
  • Cerebral blood flow
  • Linear mixed model
  • Mild cognitive impairment

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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