Objective: To determine whether baseline aortic stiffness, measured by pulse wave velocity (PWV), relates to longitudinal cerebral grey or white matter changes among older adults given aortic stiffness.
Methods: Vanderbilt Memory and Aging Project participants free of stroke and dementia at enrollment were examined (n=279, 73±7 years, 42% female). Aortic PWV (m/s) was quantified from cardiac magnetic resonance. Multimodal 3T brain MRI included T1-weighted imaging for assessing grey matter volumes and Fluid Attenuated Inversion Recovery imaging for quantifying white matter hyperintensities (WMHs). Mixed-effects regression models related baseline aortic PWV to longitudinal grey matter volumes (total, frontal, parietal, temporal, occipital, hippocampal, and inferior lateral ventricle) and log-transformed WMHs (total, frontal, parietal, temporal, and occipital). Models were adjusted for key demographic, health, and genetic factors.
Results: Mean follow-up time was 3.2 years. Higher baseline aortic PWV was related to smaller total (β=-1154, p=0.01), temporal (β=-199, p=0.008), parietal (β=-255, p=0.02), occipital (β=-104, p=0.02), and hippocampal (β=-15, p=0.001) grey matter volume over time. Higher baseline aortic PWV was related to increased WMHs over time in the temporal (β=0.02, p<0.001) and parietal lobes (β=0.01, p=0.02).
Conclusions: In older adults, higher baseline aortic PWV related to grey matter atrophy and increased white matter hyperintensities over time. Because of unmet cerebral metabolic demands, microvascular remodeling, and increased vascular resistance, arterial stiffening may preferentially affect certain highly active brain regions like the temporal and parietal lobes. Interestingly, these same regions correspond to areas of early Alzheimer’s disease pathology deposition.