Correlation between the Resistive Index Values of Renal and Orbital Arteries

Abstract

BACKGROUND: Resistive index (RI) is an indirect measurement of blood flow resistance that can be used to evaluate vascular damage. AIMS: The purpose of this study is to evaluate the association between RI values of orbital and intrarenal arteries by means of Doppler ultrasonography (US). METHODS: We evaluated 103 diabetic patients. As a control group, 30 subjects were examined. The patients were divided into two groups. Group 1 consisted of patients with urinary albumin excretion (UAE) <300 mg/day and estimated glomerular filtration rate (eGFR) levels >90 ml/min (n = 50); Group 2 had a UAE >300 mg/day and/or eGFR levels between 89 and 60 ml/min (n = 53). The association between RI values obtained with Doppler US of the ophthalmic artery, central retinal artery, posterior ciliary artery and intrarenal arteries were calculated. RESULTS: Both orbital and intrarenal arterial RI values in Group 1 and Group 2 were higher than the control group (p = 0.001); furthermore, values were higher in Group 2 than in Group 1 (p = 0.0004/0.029/0.036, p = 0.016, respectively). A positive correlation was found between orbital and intrarenal arterial RI values in Group 2 (r = 0.475, 0.285, 0.363, p < 0.01, respectively). CONCLUSION: Both orbital and renal arterial RI values were shown to be higher than the control group. Further, a trend towards higher RI values was observed with renal disease. RI may be useful as one of the markers for early diagnosis and follow-up of diabetic nephropathy and retinopathy.