Mitigating AKI After Cardiac Surgery: Is Remote Ischemic Preconditioning Ready for Prime Time?

Background: Acute kidney injury (AKI) is a common complication after cardiac surgery and is associated with significant morbidity and mortality. Remote ischemic preconditioning (RIPC), i.e., iatrogenic brief cycles of ischemia and reperfusion, has emerged as a non-pharmacological method to prevent ischemic injury in various organs. Given that low renal perfusion is considered central to the pathogenesis of cardiac surgery-associated acute kidney injury (CSA-AKI), we sought to explore the impact of RIPC in this setting based on the findings of contemporary trials. Methods: The PubMed database was searched for articles cited therein using the keywords “cardiac surgery”, “acute kidney injury”, and “remote ischemic preconditioning”. Available data from randomized controlled trials published between January 2015 and March 2025 were included. The studies were selected if 1) they explored the risk factors for AKI after cardiac surgery and 2) included data on RIPC. Pertinent information on clinical and laboratory parameters (e.g., history of heart failure, incidence of AKI, and changes in CVP) were extracted and reviewed. Results: A total of 14 trials with 4,532 participants were included. The mean age of the patients was 64 years, and 65% were men. Cardiac surgeries commonly included coronary artery bypass grafting and valve surgery, with a mean cross-clamp time of 70 minutes. Baseline serum creatinine was 1.1 mg/dl. There was substantial variation in the protocols of RIPC and the definition of AKI (e.g., timing of serum creatinine measurement and inclusion of urine output). The incidence of AKI was reported from 5.1 to 93% (mean 39%) in the control arm and from 6.1 to 68% (mean 29%) in the RIPC arm. Only 4 studies were able to show a significant salutary impact of RIPC on the prevention of CSA-AKI. Conclusion: Although RIPC has emerged as a mechanistically relevant method to mitigate the deleterious impact of ischemia in a variety of clinical settings, its protective window remains poorly understood. This study shows that (1) in the absence of a specific molecular biomarker, there is considerable variability in the timing and protocols used to deliver RIPC as well as the timing and definition of AKI, and (2) currently available data is inconclusive regarding the potential efficacy of RIPC in the prevention of CSA-AKI.