Association between retinal vessel caliber and arterial stiffness in a population comprised of normotensive to early-stage hypertensive individuals

Abstract

Background: Although impairment of the micro- and macrocirculation is considered inherent to sustained hypertension, there is a substantial lack of studies investigating whether an association exists between micro- and macrovascular damage, especially in early-stage hypertension.

Methods: We studied a meticulously selected population, free of diabetes and cardiovascular disease, of 223 individuals: 137 never-treated, newly diagnosed patients with recent onset of hypertension and 86 normotensive individuals. Nonmydriatic retinal photography was used to assess retinal microvascular diameters, including central retinal arteriolar (CRAE) and venular equivalent and arteriovenous ratio (AVR). Arterial stiffness was evaluated by measurement of pulse wave velocity (PWV) and aortic augmentation index (AIx).

Results: Compared with normotensive subjects, hypertensive patients exhibited significantly increased PWV (8.1 vs. 7.1 m/sec; P < 0.001) and AIx (23.86% vs. 18.8%; P = 0.01) and decreased CRAE (86.47 vs. 91.44 μm; P = 0.001) and AVR (0.74 vs. 0.78; P = 0.007). A significant inverse association was demonstrated between PWV and CRAE (r = -0.205; P = 0.002), which remained significant after multivariable analysis. Likewise, CRAE (P = 0.04) and AVR (P = 0.02) were independent predictors of AIx.

Conclusions: This study shows for the first time an association between quantitatively assessed retinal abnormalities and increased arterial stiffness in a sample of early-stage hypertensive and normotensive individuals, suggesting that micro- and macrocirculation impairment in hypertension is a dynamic, mutual, interdependent process present from its very early stages. Given the predictive value of both retinal arteriolar narrowing and arterial stiffness in terms of cardiovascular mortality and morbidity, identification of combined micro- and macrovascular damage might be helpful in cardiovascular risk stratification of hypertensive patients.

Keywords: arterial stiffness; arteriovenous ratio; blood pressure; hypertension; hypertensive retinopathy; macrocirculation; microcirculation; pulse wave velocity..