INFLUENCE OF RENAL FUNCTION ON RETINAL VASCULAR DENSITY ASSESSED BY OCT ANGIOGRAPHY IN HYPERTENSIVE PATIENTS

Abstract

Objective: It is well known that the retinal vasculature may be considered as a window through which the body microcirculation can be easily, safely and repeatedly, observed. Alterations of the renal microcirculation have been documented in animal models with hypertensive renal damage and microvasculature changes have been suggested to play a mayor etiological role in a large proportion of subjects with chronic CKD. Angio OCT is a recently developed noninvasive diagnostic imaging technique that employs motion contrast extracted from high-speed OCT images to produce depth-resolved, high-resolution images of retinal and choroidal vasculature without dye injection. Aim: Our study was aimed to assess in hypertensive patients the influence of renal function on retinal vascular density assessed by Angio-OCT. Design and method: We enrolled 120 consecutive hypertensive subjects (age: 51 ± 13 years; males 68%) attending our Hypertension Centre. All the patients underwent routine biochemical evaluation and angio-OCT. The retinal angiograms obtained allowed to assess vascular density of both superficial (DRS) and deep (DRP) network in the parafoveal area. Only one eye of each subject was randomly selected for analysis. Glomerular filtration rate was estimated by CKD-EPI equation. Results: 26 subjects showed a GFR value < 60 ml/min/ 1.73 m2. These patients, when compared to those with higher GFR, showed significantly lower values of DRS (36.48 ± 1.23 vs 37.29 ± 0.78 %; p < 0.001) and of DRP (37.69 ± 1.23 vs 38.34 ± 0.97 %; p = 0.005). Moreover, the GFR correlated directly with DRP (r = 0.385; p < 0.001) and with DRS (r = 0.247; p < 0.01). These associations remain statistically significant even after adjustment for age, BP and other confounders in multiple linear regression analyses (respectively, beta = 0.265; p < 0.05 e beta 0.211; p < 0.05). Conclusions: Our study, showing a significant association between reduced retinal vascular density and renal function impairment, confirms the close link relating CKD with retinal vascular abnormalities.