Association between arterial stiffness and cerebrovascular resistance in the elderly.

Arterial stiffness is an established cardiovascular risk factor influencing haemodynamic properties in the microcirculation. We tested the hypothesis that increased arterial stiffness is associated with an increase in cerebrovascular resistance in the elderly. Brachial-ankle pulse wave velocity (baPWV), using arterial tonometry, and anterior cerebral blood flow (aCBF), using extracranial ultrasound, were measured in 26 participants (67-92 years). Non-parametric statistics examined relationships between age, blood pressure, baPWV, cerebrovascular resistance (CVRi) and aCBF. Bivariate analysis suggested that baPWV was the only vascular characteristic associated with CVRi (r(s)=0.59; P=0.002). CVRi was strongly correlated with aCBF (r(s)=-0.89; P<0.001). Furthermore, compared with participants in the lower three quartiles of baPWV (LO), those in the upper quartile (HI) had elevated CVRi (median (interquartile range); HI: 0.240 (0.143) mm Hg ml(-1) min(-1); LO: 0.197 (0.072) mm Hg ml(-1) min(-1); P=0.02), and tended to have lower aCBF (HI: 394 (155) ml min(-1); LO: 459 (154) ml min(-1); P=0.09). This study found a positive correlation between baPWV and CVRi in the elderly, suggesting that haemodynamic characteristics associated with arterial aging influence cerebral circulation.