A Novel Preoperative Risk Assessment Tool to Identify Patients at Risk of Contrast-Associated Acute Kidney Injury After Endovascular Abdominal Aortic Aneurysm Repair

Abstract

Contrast-associated acute kidney injury (CA-AKI) after endovascular abdominal aortic aneurysm repair (EVAR) is associated with mortality and morbidity. Risk stratification remains a vital component of preoperative evaluation. We sought to generate and validate a preprocedure CA-AKI risk stratification tool for elective EVAR patients. We queried the Blue Cross Blue Shield of Michigan Cardiovascular Consortium database for elective EVAR patients and excluded those on dialysis, with a history of renal transplant, death during procedure, and without creatinine measures. Association with CA-AKI (rise in creatinine > 0.5 mg/dL) was tested using mixed-effects logistic regression. Variables associated with CA-AKI were used to generate a predictive model via a single classification tree. The variables selected by the classification tree were then validated by fitting a mixed-effects logistic regression model into the Vascular Quality Initiative dataset. Our derivation cohort included 7,043 patients, 3.5% of whom developed CA-AKI. After multivariate analysis, age (odds ratio [OR] 1.021, 95% confidence interval [CI] 1.004-1.040), female sex (OR 1.393, CI 1.012-1.916), glomerular filtration rate (GFR) < 30 mL/min (OR 5.068, CI 3.255-7.891), current smoking (OR 1.942, CI 1.067-3.535), chronic obstructive pulmonary disease (OR 1.402, CI 1.066-1.843), maximum abdominal aortic aneurysm (AAA) diameter (OR 1.018, CI 1.006-1.029), and presence of iliac artery aneurysm (OR 1.352, CI 1.007-1.816) were associated with increased odds of CA-AKI. Our risk prediction calculator demonstrated that patients with a GFR < 30 mL/min, females, and patients with a maximum AAA diameter of > 6.9 cm are at a higher risk of CA-AKI after EVAR. Using the Vascular Quality Initiative dataset (N=62,986), we found that GFR < 30 mL/min (OR 4.668, CI 4.007-5.85), female sex (OR 1.352, CI 1.213-1.507), and maximum AAA diameter > 6.9 cm (OR 1.824, CI 1.212-1.506) were associated with an increased risk of CA-AKI after EVAR. Herein, we present a simple and novel risk assessment tool that can be usedpreoperatively to identify patients at risk of CA-AKI after EVAR. Patients with a GFR <30 mL/min, maximum AAA diameter > 6.9 cm, and females who are undergoing EVAR may be at risk for CA-AKI after EVAR. Prospective studies are needed to determine the efficacy of our model.