Researchers here note the clear correlation between a measure of arterial stiffness and various assessments of damage and dysfunction to the brain. Arterial stiffness leads to hypertension via its disruption of the feedback systems needed to control blood pressure. That in turn leads to pressure damage to delicate tissues, such as those of the brain. It is associated with dysfunction of the blood-brain barrier, allowing leakage of normally restricted cells and molecules that provoke inflammation in brain tissues, as well as other vascular issues that cause harm to the brain.
We examined the associations of carotid artery stiffness with cerebral small-vessel disease markers, cognition, and dementia subtypes in a memory clinic cohort. A total of 272 participants underwent carotid ultrasonography, brain magnetic resonance imaging, and neuropsychological assessment. Carotid ultrasonography was used to assess β-index, pressure-strain elastic modulus, and pulse-wave velocity-β.
Brain magnetic resonance images were graded for cerebral small-vessel disease markers, including white matter hyperintensities, lacunes, and cerebral microbleeds. Participants were classified as having no cognitive impairment, cognitive impairment and no dementia, or dementia subtyped as Alzheimer disease and vascular dementia. Cognition was assessed using National Institute of Neurological Disorders and Stroke / Canadian Stroke Network harmonization battery.
After adjusting for age, sex, cardiovascular risk factors, and diseases, multivariable models showed that β-index, elastic modulus, and pulse-wave velocity-β were associated with white matter hyperintensities, and elastic modulus (odds ratio [OR] 1.39) and pulse-wave velocity-β (OR 1.47) were independently associated with lacunes. Similarly, β-index (OR 2.04), elastic modulus (OR 2.22), and pulse-wave velocity-β (OR 2.50) were independently associated with vascular dementia. Carotid stiffness measures were independently associated with worse performance in global cognition, visuomotor speed, visuospatial function, and executive function. These associations became largely nonsignificant after further adjusting for cerebral small-vessel disease markers.
Thus in memory clinic patients, carotid artery stiffness was associated with white matter hyperintensities and lacunes, impairment in global and domain-specific cognition, and causative subtypes of dementia, particularly vascular. The effects of carotid stiffness on cognition were not independent of, and were partially mediated by, cerebral small-vessel disease.