Background: It is known that essential hypertension may be implicated in the development of cognitive impairment that is associated to microvascular disease of the brain. It has been hypothesized that increased arterial stiffness of the large arteries may lead to microvascular changes due to increased pulsatile flow. Our study tests the hypothesis that large artery stiffness and microvascular damage are related to brain microcirculation changes as reflected by impaired cognitive function.
Methods: We studied 110 nondiabetic patients aged 40-80 years (mean age 53.8 +/- 11.2 years, 57 men) with recently diagnosed stage I-II essential hypertension. Mini-Mental State Examination (MMSE) was used as a screening test for global cognitive impairment. We performed both 2-D echocardiography and carotid-femoral pulse wave velocity (PWV) in order to evaluate arterial stiffness. Twenty-four hour urine microalbumin excretion was measured as a marker of microvascular damage.
Results: In the entire population, MMSE was negatively correlated with age (r = -0.42, P < 0.001), 24-h pulse pressure (PP) (r = -0.18, P < 0.05), and PWV (r = -0.3, P = 0.003). Additionally, MMSE was not independently correlated with microalbuminuria in patients aged over 65 years (r = -0.58, P = 0.003).
Conclusions: Impaired cognitive function is associated with increased large artery stiffness and microalbumin excretion in newly diagnosed, untreated hypertensive patients. These findings support the hypothesis that cognitive impairment induced by impaired microcirculation is linked to large artery stiffness and microvascular damage.