Extracorporeal Blood Purification and Acute Kidney Injury in Cardiac Surgery: The SIRAKI02 Randomized Clinical Trial

Abstract

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.

Figure 1.. Flow of Patients in the Trial

^aIt was not possible to obtain consent on account of timing (failure to obtain consent the day before surgery because patients were admitted late in the afternoon when research assistants were not available) for 489 patients and 58 did not sign informed consent. ^bRandomization was stratified by center (2:1) according to expected recruitment rates. In 6 cases, envelopes were opened by 2 different research fellows for the same patient, but that patient only received 1 group assignment. For clarity, these duplications have been excluded from the randomization in the flowchart.

Figure 2.. Risk Factors for Cardiac Surgery–Associated Acute Kidney Injury (CSA-AKI) Within 7 Days

CABG indicates coronary artery bypass graft.