Extracorporeal Blood Purification and Acute Kidney Injury in Cardiac Surgery

Importance: Cardiac surgery-associated acute kidney injury (CSA-AKI) remains a significant problem following cardiopulmonary bypass (CPB). Various strategies are proposed to attenuate CSA-AKI, including extracorporeal blood purification (EBP), but little is known about the effect of EBP through an acrylonitrile-sodium methallylsulfonate/polyethyleneimine membrane during CPB. Objective: To determine whether the use of an EBP device in a nonemergent cardiac surgery population reduces CSA-AKI after CPB. Design, Setting, and Participants: This double-blind, randomized clinical trial was conducted in 2 tertiary hospitals in Spain. Patients 18 years or older undergoing nonemergent cardiac surgery who were at high risk for CSA-AKI were enrolled from June 15, 2016, through November 5, 2021, with follow-up data through February 5, 2022. Of 1156 patients assessed, 343 patients were randomized (1:1) to either receive EBP or standard care. Intervention: Nonselective EBP device connected to the CPB circuit. Main Outcomes and Measures: The primary outcome was the rate of CSA-AKI in the 7 days after randomization. Results: Among 343 patients randomized (169 to receive EBP and 174 to receive usual care), the mean (SD) age was 69 (9) years and 119 were females. The rate of CSA-AKI was 28.4% (95% CI, 21.7%-35.8%) in the EBP group vs 39.7% (95% CI, 32.3%-47.3%) in the standard care group (P = .03), with an adjusted difference of 10.4% (95% CI, 2.3%-18.5%) using a log-binomial model (P = .01). No significant differences (P > .05) were observed in most of the predefined clinical secondary end points or post hoc exploratory end points. In a sensitivity analysis, EBP was found to be more effective in terms of CSA-AKI reduction in patients with chronic kidney disease, diabetes, hypertension, low left ventricular ejection fraction (<40%), and lower body mass index (<30). No differences were observed between the groups in adverse events tracking. Conclusions and Relevance: The use of a nonselective EBP device connected to the CPB circuit in a nonemergent population of patients undergoing cardiac surgery was associated with a significant reduction of CSA-AKI in the first 7 days after surgery. Trial Registration: ClinicalTrials.gov Identifier: NCT02518087.