(1420) Renal Angina Index (RAI) as a Predictor of Renal Injury Progression in Patients on ECMO Support

Introduction: The Renal Angina Index (RAI) was initially developed for pediatric populations to predict the progression to acute kidney injury (AKI) based on KDIGO criteria. Its importance lies in identifying the development and severity of AKI by assessing changes in creatinine levels, fluid balance, the need for vasopressors, and the use of mechanical ventilation, as well as a history of diabetes mellitus and ICU admission . Consequently, renal angina can serve as an early biomarker for detecting renal impairment. AKI is a common complication in the ICU, with an incidence of 60%,In patients on ECMO support.
The RAI is a measurable and accessible tool that has proven to be a predictor of mortality in adult populations, independent of AKI and RRT. The variables included in RAI are applicable to ECMO support. This study assesses the validity of RAI in predicting the severity and progression of AKI in patients admitted for ECMO support.

Methods: This retrospective cohort study includes patients with ECMO support, between 2019 and 2023. Upon admission, RAI was calculated, validating the severity and progression of renal injury. The accuracy of the RAI was then compared with APACHE II, SOFA, DEOx, SAVE, and RESP to assess severity in patients in ECMO support.

Results: 272 patients were included. 56.9% presented with renal angina, 81.9% progressed to acute kidney injury, requiring renal therapy 50.3% and 41.3%died, yielding an RAI score of 9.6. Variables most associated with developing renal angina included, use of vasoactive agents such as noradrenaline OR 4.54 (95% CI, 2.42-8.53; p < 0.001), DEOx OR 1.15 (95% CI, 1.03-1.07; p < 0.001), VA ECMO therapy OR 3.99 (95% CI, 2.14-7.40; p < 0.001), and pre-support potassium OR 3.14 (95% CI, 2.05-4.82; p < 0.001). The RAI in patients requiring ECMO support showed an AUROC curve of 0.756 (95% CI, 0.70 – 0.80) for predicting AKI, 0.604 (95% CI, 0.50 – 0.70) for predicting AKI severity progression according to KDIGO stage, and 0.615 (95% CI, 0.52 – 0.70) for predicting the need for RRT

Conclusions: Our study is the sole documentation of RAI's utility in predicting AKI severity and progression among ECMO-supported patients, serving as a reliable and practical method for daily clinical application.