A Clinical Association between an Increasing Renal Resistive Index and the Atherosclerotic Burden in Patients with a Preserved Renal Function

Objective A positive correlation is observed between the progression of renal impairment and the increasing risk of cardiovascular disease. Our aim was to examine the relationship between the renal resistive index (RRI) assessed by duplex sonography and the extent of atherosclerosis in patients without renal impairment undergoing vascular imaging studies. Methods The RRI was evaluated pre-procedurally among 106 outpatients with an estimated glomerular filtration rate (eGFR) >= 60 mL/min/1.73 m(2) undergoing clinically-driven coronary computed tomography angiography (CCTA). In those subjects, a carotid artery ultrasound scan was also performed to evaluate carotid artery disease. We investigated the association between the RRI and the atherosclerotic extent, defined by the presence of coronary artery calcium (CAC)>0 and carotid intima-media thickness (cIMT)>= 1.0 mm. Results Multi-site atherosclerosis (CAC>0 and cIMT >= 1.0 mm) was found in 31 patients. The RRI was significantly increased with an increasing number of atherosclerotic vessels (absence of atherosclerosis: 0.65 +/- 0.04 vs. single-site atherosclerosis: 0.67 +/- 0.06 vs. multi-site atherosclerosis: 0.71 +/- 0.05, p<0.001). A multivariate logistic regression analysis showed that RRI>0.70 [odds ratio (OR): 4.05, 95% confidence interval (CI), 1.37-12.0, p=0.011, cardio ankle vascular index (CAVI)>= 9.0 (OR: 8.18, 95% CI: 2.47-27.1, p<0.01), diabetes (OR: 4.34, 95% CI: 1.37-13.7, 1 - 0.01) and an eGFR>90 mL/min/1.73 m(2) (OR: 5.89, 95% CI: 1.39-25.1, p= 0.01) were associated with multi-site atherosclerosis. Conclusion The RRI, a sub-clinical renal parameter is an atherosclerotic marker in patients without renal impairment.