Higher Aortic Stiffness Is Related to Lower Cerebral Blood Flow and Preserved Cerebrovascular Reactivity in Older Adults

BACKGROUND:Mechanisms underlying the association between age-related arterial stiffening and poor brain health remain elusive. Cerebral blood flow (CBF) homeostasis may be implicated. This study evaluates how aortic stiffening relates to resting CBF and cerebrovascular reactivity (CVR) in older adults. METHODS:Vanderbilt Memory & Aging Project participants free of clinical dementia, stroke, and heart failure were studied, including older adults with normal cognition (n=155; age, 72±7 years; 59% male) or mild cognitive impairment (n=115; age, 73±7 years; 57% male). Aortic pulse wave velocity (PWV; meters per second) was quantified from cardiac magnetic resonance. Resting CBF (milliliters per 100 g per minute) and CVR (CBF response to hypercapnic normoxia stimulus) were quantified from pseudocontinuous arterial spin labeling magnetic resonance imaging. Linear regression models related aortic PWV to regional CBF, adjusting for age, race/ethnicity, education, Framingham Stroke Risk Profile (diabetes mellitus, smoking, left ventricular hypertrophy, prevalent cardiovascular disease, atrial fibrillation), hypertension, body mass index, apolipoprotein E4 (APOE ε4) status, and regional tissue volume. Models were repeated testing PWV×APOE ε4 interactions. Sensitivity analyses excluded participants with prevalent cardiovascular disease and atrial fibrillation. RESULTS:Among participants with normal cognition, higher aortic PWV related to lower frontal lobe CBF (β=−0.43; P=0.04) and higher CVR in the whole brain (β=0.11; P=0.02), frontal lobes (β=0.12; P