The Association between Carotid Intima-Media Thickness and Cognitive Impairment: A Systematic Review and Meta-Analysis

Abstract

<b><i>Background:</i></b> Emerging evidence suggests that cognitive impairment (CI) and different etiologies of dementia, including Alzheimer’s disease (AD), are associated with vascular risk factors and atherosclerosis. In clinical practice, carotid intima-media thickness (CIMT) measured by ultrasonography may be a marker of atherosclerosis. Many studies report increased CIMT in patients with dementia and CI although a firm association has not yet been established. <b><i>Aim:</i></b> This systematic review and meta-analysis were conducted to study the relationship between CIMT, dementia, and CI. <b><i>Methods:</i></b> The literature search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and included the following databases: Medline, Embase, Cochrane Library, and Epistemonikos. The search spanned from 2000 to 2020 and was limited to English and Scandinavian languages. <b><i>Results:</i></b> The main analysis of CIMT in subjects with CI compared to subjects with no cognitive impairment (NCI) included 12 studies; 1,089 subjects with CI and 5,223 with NCI. There was no significant difference in CIMT between the CI and NCI groups. However, subgroup analyses revealed significantly higher CIMT in the mild cognitive impairment (MCI) and dementia groups than the NCI group. In addition, patients with dementia had increased CIMT compared to patients with MCI, and patients with AD demonstrated higher CIMT than those with vascular cognitive impairment (VCI). <b><i>Conclusion:</i></b> CIMT may be higher in subjects with CI than in cognitively healthy subjects although no significant difference was observed in our main analysis. CIMT was higher in the dementia group than the MCI group and in the AD group compared to the VCI group.

Cerebrovascular Hemodynamics in Cognitive Impairment and Dementia: A Systematic Review and Meta-Analysis of Transcranial Doppler Studies

“…This review and meta-analysis does not answer the question regarding whether disturbances in cerebral hemodynamics play a role in the neurodegenerative process or are merely prodromal to cognitive decline and dementia. Vascular risk factors and vascular disturbances with subsequent brain hypoperfusion are considered part of the pathophysiological process in VaD, and increasing evidence shows that vascular risk factors and atherosclerosis may contribute in the AD process as well [ 58 , 59 ]. It is possible that reduced blood flow to the brain with subsequent cerebral hypoperfusion could result in nerve cell dysfunction and death, particularly in vulnerable areas including the hippocampi.…”

Relationship between carotid intima-media thickness and white matter hyperintensities in non-stroke adults: a systematic review

“…Hence, deciphering the CIMT-WMH relationship is crucial in the field of vascular and neurological research, since they are associated with various clinical conditions including cognitive decline, AD, and increased risk of future stroke outcomes ( Ye et al, 2018 ). Previously systematic reviews have focused on the relationship between CIMT and cognitive decline ( Fresnais et al, 2021 ), emphasized the carotid stenosis severity and white matter subtypes ( Ye et al, 2018 ), and included symptomatic/stroke patients, who may be susceptible to pre-existing white matter alterations ( Liao et al, 2015 ). Therefore, it can be inferred that the CIMT-WMH relationship has been earlier reported with inconclusive findings and thus necessitates a further meticulous investigation.…”

Association between Carotid Intima-Media Thickness (CIMT) and Alzheimer’s Disease Detected by 99mTc- ECD SPECT of Brain

“…A comprehensive review and meta-analysis revealed significantly higher CIMT in groups with dementia and mild cognitive impairment (MCI) compared to those without cognitive impairment (7). Additionally, patients with Alzheimer's disease (AD) exhibited considerably higher CIMT than those with non-AD dementia (6,11).…”