INVERSE RELATIONSHIPS BETWEEN CHOROIDAL THICKNESS AND RENAL RESISTANCE INDEX IN HYPERTENSIVE PATIENTS

Abstract

Introduction: Alterations of the renal microcirculation have been documented in animal models of hypertensive renal damage. Traditionally, the retina has been considered the easiest accessible window to study the systemic microcirculation, even though the choroid is the most important vascular layer of the eye. The introduction in the past few years of advanced optical coherence tomography (OCT) techniques has greatly increased our understanding of the choroid. Although the renal resistive index (RRI) was initially considered to reflect intrarenal vascular pathological processes, this index is actually regarded as the result of complex interaction between renal and systemic vascular wall properties and hemodynamic factors, and it is endowed with prognostic implications.Aim: To analyse the relationships between choroidal thickness (CT) and RRI in a group of hypertensive patients. Methods: We enrolled 66 nondiabetic essential hypertensives (67% men; mean age: 52 ± 12 years), consecutively attending our Hypertension Centre. Results: The glomerular filtration rate (GFR) estimated by the CKD-EPI equation was 78 ± 2 ml/min/1.73 m2, and the RRI 0.64 ± 0.07. Splitting the study population into 2 groups on the basis of the 75th percentile of the distribution of RRI, we found lower choroidal thickness in the group with greater values of RRI (all p.001; Figure 3). We observed also significant inverse correlations between CT and RRI, that held even after adjustment for GFR, age and gender (Table 3). Conclusions: Our findings confirm the close relationships between changes in the ocular microcirculation and renal dysfunction and suggest that intrarenal hemodynamic alterations are involved in these relationships.