Among cognitively normal older adults without clinical dementia, stroke, or heart failure, greater aortic stiffening is associated with lower regional cerebral blood flow (CBF) and higher cerebrovascular reactivity (CVR), particularly in those with an increased genetic predisposition for Alzheimer’s disease, according to study results published in Circulation.
The investigators sought to explore how aortic stiffening is linked with resting CBF and CVR in older adults. A total of 270 adults were enrolled in the longitudinal study, with 155 in the normal cognition (NC) cohort and 115 in the mild cognitive impairment (MCI) cohort. In the NC arm, 59% of participants were men, with a mean age of 72±7 years, and 57% of participants in the MCI arm were men, with a mean age of 73±7 years. Aortic pulse wave velocity (PWV m/sec) measurements were based on cardiac resonance imaging.
According to linear regression models, higher aortic PWV in the NC group was associated with significantly lower frontal lobe CBF (P =.04), as well as significantly higher CVR in the whole brain (P =.02), frontal lobes (P <.05), temporal lobes (P =.02), and occipital lobes (P =.01). Among NC participants who were carriers of APOE ε4, study findings were even more pronounced, with higher PWV associated with lower brain CBF (P =.047), lower temporal lobe CBF (P =.004), and higher temporal CVR (P =.08), although this measurement was not statistically significant.
Among those in the MCI arm, higher aortic PWV was associated with significantly lower CBF in the occipital lobe (P =.02), but this finding was diminished when those with prevalent cardiovascular disease and atrial fibrillation were excluded. In MCI APOE ε4 carriers, the results were more pronounced, with higher PWV significantly associated with lower temporal lobe CBF (P =.02).
The investigators concluded that central arterial stiffening may contribute to decreases in regional CBF, despite cerebrovascular reserve capacity. The findings from this study add to a growing body of research that underscores the interrelationship between cardiovascular function and brain health among aging adults. Understanding this association may lead to earlier detection and targeted interventions to prevent or lessen the onset of more serious cerebrovascular damage linked with higher aortic stiffening.
Jefferson AL, Cambronero FE, Liu D, et al. Higher aortic stiffness is related to lower cerebral blood flow and preserved cerebrovascular reactivity in older adults [published online July 17, 2018]. Circulation. doi: 10.1161/CIRCULATIONAHA.118.032410