Contrast-Associated Acute Kidney Injury After Thrombectomy for Ischemic Stroke

Background and Objectives Contrast-associated acute kidney injury (CA-AKI) is a potentially preventable complication after exposure to iodinated contrast media. In patients undergoing endovascular thrombectomy (EVT) for acute ischemic stroke (AIS), the incidence and clinical impact are poorly characterized, and no validated prediction tool is currently available. The aim of this study was to assess the incidence and prognostic significance of CA-AKI in EVT-treated patients with AIS and to develop and validate a predictive score. Methods A retrospective, multicenter cohort study was conducted involving EVT-treated patients across 73 centers in 16 countries (January-December 2023). Inclusion criteria were age >= 18 years, absence of dialysis, availability of preprocedural and 48-hour postprocedural creatinine levels, and available 90-day follow-up (modified Rankin Scale [mRS] score). The primary outcome was CA-AKI, defined by KDIGO (Kidney Disease: Improving Global Outcomes criteria;creatinine increase >= 0.3 mg/dL or >= 1.5 times baseline, within 48 hours). Secondary outcomes were (1) in-hospital mortality, (2) 90-day mRS score, and (3) 90-day severe disability or death (mRS score >3). Logistic models assessing associations with outcomes accounted for within-center clustering by applying robust standard errors. CA-AKI prediction models were developed across imputed data sets using univariable selection (p < 0.20), backward elimination (p < 0.05), and coefficient-based scoring after categorization of continuous predictors, with internal validation by bootstrap to obtain optimism-adjusted estimates. Results Among 6,638 patients (median age 74 years; 48.7% male), CA-AKI occurred in 326 (4.9%) and was independently associated with in-hospital mortality (adjusted odds ratio [aOR] 2.269; 95% CI 1.615-3.190), higher 90-day mRS scores (adjusted common odds ratio 1.584; 95% CI 1.110-2.258), and 90-day severe disability or death (aOR 1.530; 95% CI 1.057-2.216). A preprocedural risk model including 12 routine clinical variables-sex, ethnicity, arterial hypertension, dyslipidemia, chronic kidney disease, antiplatelet therapy, NIH Stroke Scale score at admission, serum glucose, estimated glomerular filtration rate, hemoglobin, mean arterial pressure, and IV thrombolysis-demonstrated acceptable discrimination (area under the receiver operating characteristic curve 0.710 [95% CI 0.682-0.738]; precision-recall area under the curve 0.13 [95% CI 0.10-0.16]), good calibration (slope 0.870 [95% CI 0.759-0.928]), good overall performance (Brier score 0.045 [95% CI 0.042-0.049]). A second model that included EVT-related variables (e.g., contrast volume) showed similar performances. Discussion In this large, international cohort, CA-AKI occurred in approximately 1 in 20 EVT-treated patients with AIS and was independently associated with poor outcomes. A simple preprocedural risk score enables early identification of high-risk individuals and may support preventive strategies.