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

Abstract

Background: 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. Methods: 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. Results: 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. Conclusions: Herein, we present a simple and novel risk assessment tool that can be used preoperatively 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.