Correlations Between Choroidal Thickness and Carotid Artery Doppler Variables in Diabetic Patients Without Diabetic Retinopathy

Abstract

Purpose : Choroid receives nearly 70% of ocular blood flow, being sensitive to vascular changes of Diabetes Mellitus (DM), such as systemic atherosclerosis. A choroidal vasculopathy may play a role in diabetic retinopathy (DR) pathogenesis. Once carotid ultrasound (US) is currently used to the screening of systemic atherosclerosis, we performed a prospective cohort study to correlate choroid thickness (CT) with carotid US in patients with type 2 DM without DR.

Methods : We analyzed 17 eyes and 17 carotid US of 17 diabetic patients without DR (13 females and 4 males; mean age 65.3 ± 10.3 years). The CT was measured with Optical Coherence Tomography using the Enhanced Depth Imaging software (OCT-EDI, Heidelberg Engineering®), at 13 different locations (subfoveal and 3 measurements 500 μm apart in all 4 directions - nasal, temporal, superior and inferior). Common and Internal Carotid Arteries (CCA and ICA, respectively) US were performed and the hemodynamic variables included in the study are the Peak Systolic Velocity (PSV), End-Diastolic Velocity (EDV) and Resistance Index (RI). The anatomic variable in study is the Intima-Media Thickness of CCA (CIMT). Systemic Blood Pressure (SBP) and Ocular Pulse Amplitude (OPA) were assed as well. The variables previously indicated are analyzed using nonparametric tests and Spearman correlations.

Results : Choroidal Thickness at 1500 μm inferior to the fovea correlated negatively with the RI of both ICA and CCA (p = 0.022 and 0.035, r = -0.55 and -0.52, respectively). Choroidal Thickness is not correlated with PSV, EDV, RI and CIMT, neither with SBP and OPA in any of the other sites (p > 0.05). The SBP is positively correlated with PSV and RI of ICA (p = 0.003 and 0.030, r = 0.69 and 0.53, respectively).

Conclusions : The absence of correlation between carotid US and CT in all quarters except in the 1500 μm inferior to the fovea lead us to infer that the diabetic choroidopathy, already identified in previous studies, is a localized microangiopathy. The OCT is a non-invasive tool that may allow the identification of early preclinical manifestations of diabetic eye disease.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.