Echolucent Carotid Plaque is Associated with Future Renal Dysfunction in Patients with Stable Coronary Artery Disease

AIM: Functional and structural abnormalities of the peripheral arteries are associated with renal dysfunction, independent of the presence of renal artery stenosis. This study investigated whether echolucent carotid plaque is associated with a future decline in the renal function in patients with coronary artery disease (CAD). METHODS: Ultrasound assessments of carotid plaque echolucency with integrated backscatter (IBS) analyses were performed in 327 patients with stable CAD and carotid plaque who exhibited a normal renal function (estimated glomerular filtration rate [eGFR] ≥60 mL/min/1.73 m(2)) at baseline. A lower IBS value reflects the presence of echolucent and lipid-rich unstable plaque. All patients were followed up for 36 months or until the occurrence of renal dysfunction, defined as an eGFR of ＜45 mL/min/1.73 m(2). RESULTS: During the follow-up period, 39 patients developed renal dysfunction. A multivariate logistic regression analysis showed that the presence of carotid plaque with a low IBS value was significantly associated with progression to renal dysfunction (odds ratios 0.48; 95% CI 0.30-0.78, p= 0.003). In addition, carotid plaque with a low IBS value had a significant incremental effect on the predictive value of known risk factors for renal dysfunction in analyses using c-statistics (AUC of the baseline risk model with and without IBS: 0.83 vs. 0.79, respectively, p=0.04), net reclassification improvement (index=0.549, p=0.001) and integrated discrimination improvement (index=0.068, p=0.002). CONCLUSIONS: Echolucency of the carotid arteries is associated with future renal dysfunction in patients with stable CAD, indicating that the mechanisms related to plaque instability may be involved in the onset of renal dysfunction.