Abstract 18388: Albuminuria Determines Event-Free Survival in Atherosclerotic Renal-Artery Stenosis

Abstract

Introduction: Stenosis severity and revascularization may have little relation to outcomes in patients with atherosclerotic renal artery stenosis (ARAS). Albuminuria is a direct indicator of glomerular injury and kidney health. The effect of albuminuria on survival in people with ARAS is not well characterized. Hypothesis: Proteinuria predicts clinical events in people with ARAS. Methods: The Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) clinical trial is a prospective trial of individuals with ARAS. Patients were followed to a maximum of 8 years. Urine albumin and creatinine were measured at a single core lab and the ratio was log transformed (LUACR). The composite endpoint included: cardiovascular (CV) or renal mortality, myocardial infarction (MI), stroke, chronic heart failure (CHF), progressive renal insufficiency (PRI), and renal replacement therapy (RRT). Utilizing receiver operating characteristic (ROC) curves, we developed 3 cutoff points for the LUACR using three methods: Youden’s, closest to the top-left point and the sample median. In order to verify the cutoff point we randomly divided the sample into a training set and a verification set of equal size. Cross verification was applied and the simulation was repeated 5000 times. The analyses are controlled by age, gender, cystatin-c, and systolic blood pressure. Results: Cross verification shows that Youden’s method gives the highest specificity and accuracy. It yields an optimal cutoff point of LUACR=3.83 (UACR is exp(3.83)=46.06). Subjects with values above this threshold, in the verification sample, had higher rates of the composite event rate (50% vs. 27%), PRI (27% vs. 13%), and CHF (16% vs. 5%), all p<0.001; CV death (13% vs. 7%), and all-cause mortality (14% vs. 7%), both p<0.01. Conclusions: Albuminuria powerfully predicts adverse cardiovascular and renal events, including all-cause mortality, in people with ARAS.