Aortic Pulse Wave Velocity Predicts Focal White Matter Hyperintensities in a Biracial Cohort of Older Adults

Abstract

While the cross-sectional relationship of arterial stiffness with cerebral small vessel disease is consistently shown in middle-aged and young-old adults, its less clear if these associations remain significant over time in very old adults. We hypothesize that arterial stiffness is longitudinally associated with white matter characteristics and associations are stronger within watershed areas. Neuroimaging was obtained in 2006–08 from 303 elderly (mean age 82.9 years, 59% women, 41% black) with pulse wave velocity measures in 1997–98. Multivariable regression models estimated the coefficients for pulse wave velocity (cm/sec) in relationship to presence, severity and spatial distribution of white matter hyperintensities, gray matter volume and fractional anisotropy from diffusion tensor, adjusting for demographic, cardiovascular risk factors and diseases from 1997–98 to 2006–08. Higher pulse wave velocity in 1997–98 was associated with greater white matter hyperintensities volume in 2006–08 within the left superior longitudinal fasciculus (age and total brain white matter hyperintensities-adjusted p=0.023), but not with white matter hyperintensities in other tracts, or with fractional anisotropy or gray matter volume from total brain (p>0.2). Associations were stronger in blacks than in whites remaining significant in fully adjusted models. Elderly with white matter hyperintensities in tracts related to processing speed and memory are more likely to have had higher pulse wave velocity values ten years prior, before neuroimaging data being available. Future studies should address whether arterial stiffness can serve as an early biomarker of covert brain structural abnormalities and whether early arterial stiffness control can promote successful brain aging, especially in black elderly.

Association of arterial stiffness with progression of subclinical brain and cognitive disease

“…In earlier cross-sectional analyses, baseline blood pressure and aortic PWV similarly predicted WMHV several years later in population-based cohorts. [28][29][30] In our sample, CFPWV was associated with WMHV, predominantly in participants aged 65 years or older, in cross-sectional analyses, 11 but was not associated with progression of WMHV. A possible explanation for this finding might be that our middle-aged cohort was relatively healthy and younger than other cohorts 10,28 in which associations between arterial stiffness and WMH have been observed.…”

“…[28][29][30] In our sample, CFPWV was associated with WMHV, predominantly in participants aged 65 years or older, in cross-sectional analyses, 11 but was not associated with progression of WMHV. A possible explanation for this finding might be that our middle-aged cohort was relatively healthy and younger than other cohorts 10,28 in which associations between arterial stiffness and WMH have been observed. Furthermore, unfavorable arterial hemodynamics may not affect all people or all areas of the brain equally: a recent study suggests a greater effect of aortic stiffness in black compared to white persons, and that elevated CFPWV may affect WMHV in certain brain regions but not others.…”

Arterial stiffness and progression of structural brain changes

“…One previous study in a community-dwelling older population found that increased aortic stiffness was associated with larger WML volume 10 years later, although the authors did not report on change in WML volume over time. 18 Although we do not have a sound explanation for the disparity between the cross-sectional and prospective findings, there are some suggestions. First, it is Table 1 Baseline characteristics of the total study sample after imputation (n 5 526) and the study sample with follow-up measurements (n 5 308) Presence of lacunar infarcts 21 20 Presence of nonlacunar infarcts 16 15 Continued possible that only severe arterial stiffness contributes to brain changes.…”

“…12 Also, stiffness of the large arteries may impair cerebral autoregulation, predisposing to hypoperfusion during hypotension, subsequently leading to ischemia. 13 Several cross-sectional studies relating arterial stiffness to the subclinical markers of dementia showed a relation between increased arterial stiffness and larger white matter lesion (WML) volumes, [14][15][16][17][18][19][20] more lacunar infarcts, 14,20,21 more brain atrophy, 12,20 and lower cerebral perfusion. 22 However, it is unknown whether arterial stiffness contributes to an increased development of ischemic and degenerative brain changes over time.…”

Association between the Cardio-Ankle Vascular Index and Executive Function in Community-Dwelling Elderly People

“…Regarding regional differences, cross-sectional and longitudinal studies showed that structural changes, such as white matter hyperintensities and lacunes, progressed with age, mainly in the frontal and parietal lobes 24,25) . Increased arterial stiffness was also associated with increased lesions mainly in the frontal lobe 26) . These lesions in the frontal lobe have been independently associated with cognitive decline, particularly in the domains of executive function 27,28,29) .…”