How much volume of iodinated contrast medium leads to acute kidney injury in endovascular aortic repair?

Background: Acute kidney injury (AKI) is a significant complication of endovascular aortic repair (EVAR), often related to iodinated contrast medium (ICM) exposure. This study aimed to analyze AKI incidence after EVAR in a monocentric case series and define a cutoff value for contrast volume (VIC) predictive of AKI. Methods: All elective EVARs performed on patients with abdominal aortic aneurysms (AAA) from 20122020 were analyzed for AKI incidence. AKI was defined by serum creatinine criteria (>0.3 mg/dL within 48 hours, >1.5x baseline within a week) or urine output criteria (<0.5 mL/kg/hour for 6 hours). Statistical analysis included Chi-square, Student's t-test, log-rank, ROC curve, and multivariate regression. Results: Among 732 patients undergoing EVAR, 27 (3.6%) developed AKI, with 21 (77.8%) cases identified as Contrast-Induced AKI (CI-AKI). AKI patients received significantly higher ICM (AKI 153 +/- 100 vs. 89 +/- 57 mL No-AKI, P=0.015). Independent predictors of AKI included preoperative CKD stage (OR1.72, 95% CI: 1.002.96, P=0.046) and intraoperative VIC >90 mL (OR=2.77, 95% CI: 1.11-6.89, P=0.025). AKI was associated with higher postoperative mortality (AKI 7.4% vs. 0.4% No-AKI, P=0.013) and prolonged hospitalization (AKI 7 +/- 6 vs. 5 +/- 5 days No-AKI, P=0.017). Survival at 24 +/- 21 months was significantly reduced in the AKI group (80 +/- 8% vs. 89 +/- 2%, P=0.026). A VIC-to-preoperative-eGFR ratio (VIC/pre-eGFR) >2.91 was predictive of CIAKI (42.9% sensitivity, 93.7% specificity). Conclusions: While infrequent, AKI after elective EVAR significantly impacts short- and long-term outcomes. Preoperative CKD stage and intraoperative VIC are key predictors. Procedures should aim for a VIC/pre-eGFR ratio <2.91 to mitigate CI-AKI risk.