Carotid and regional arterial stiffness and dementia-related imaging biomarkers in the Multi-Ethnic Study of Atherosclerosis (MESA).

INTRODUCTION: Arterial stiffness measured within various arterial beds may be differentially associated with neuroimaging biomarkers of dementia. METHODS: We related carotid and regional (cardio-ankle vascular index [CAVI] and heart-ankle pulse wave velocity [haPWV]) arterial stiffness measures to biomarkers (gray matter volume [GMV], white matter hyperintensity volume [WMHV], and fractional anisotropy [WMFA]) and amyloid positron emission tomography (PET) positivity (centiloid > 12.2), controlling for covariates. RESULTS: All arterial stiffness measures were associated with higher WMHV. Lower carotid distensibility (increased mechanical stress) was positively associated with WMFA, while Young's elastic modulus and haPWV (greater stiffness) were associated with lower WMFA. Only CAVI was significantly related to amyloid PET positivity, although similar effect sizes were observed for carotid measures. No main associations were observed with GMV. Significant interactions showed men and Black and Hispanic participants had stronger associations between carotid stiffness and GMV. CONCLUSIONS: Carotid stiffness measures were associated with WM injury while regional CAVI measures were associated with amyloid positivity. HIGHLIGHTS: We studied differences between carotid ultrasound and regional (cardio-ankle vascular index [CAVI] and heart-ankle pulse wave velocity [haPWV]) measures of arterial stiffness and neuroimaging abnormalities (white matter changes and amyloid positron emission tomography [PET] positivity) in the Multi-Ethnic Study of Atherosclerosis, a diverse cohort of older adults. Carotid measures were associated with white matter injury, demonstrated usingwhite matter hyperintensity volume and white matter fractional anisotropy, and were not associated with amyloid PET positivity. Regional measures had variable relationships with white matter injury and CAVI, and in particular, were associated with amyloid deposition. Black and Hispanic participants had significant associations between arterial stiffness measures and brain volume that were not observed in White participants. Men showed significant associations with carotid distensibility and white matter injury while women did not.