Timing of acute kidney injury and outcomes in patients receiving veno-arterial extracorporeal membrane oxygenation

Whether the timing of acute kidney injury (AKI) relative to veno-arterial extracorporeal membrane oxygenation (VA-ECMO) carries independent prognostic value remains uncertain. We evaluated the association between AKI timing and clinical outcomes in a retrospective, two-center cohort of 172 adults receiving VA-ECMO in Thailand. Patients were classified as having AKI before ECMO, AKI after ECMO, or no AKI by KDIGO creatinine criteria. Overall, 81 patients (47.1%) had AKI before ECMO, 82 (47.7%) developed AKI after ECMO, and 9 (5.2%) had no AKI. Compared with the AKI after ECMO group, patients with AKI before ECMO had more severe renal dysfunction, greater need for renal replacement therapy, more frequent acute liver injury, and higher unadjusted ICU mortality (82.7% vs 69.5%, p = 0.048). This association was attenuated after adjustment for age, sex, chronic kidney disease, and center (adjusted HR 1.39, 95% CI 0.98–1.98), and further attenuated after adjustment for illness severity (HR 1.28, 95% CI 0.86–1.90); AKI developing after ECMO initiation was not significantly associated with ICU mortality. In conclusion, AKI preceding ECMO appears to reflect pre-cannulation shock and multiorgan dysfunction in addition to renal injury, a distinction that should inform, rather than restrict, ECMO candidacy assessment.