Abstract 14823: Assessment of the Appropriateness and Prognostic Significance of the Current Universal Diagnostic Definition for Acute Kidney Injury in Patients After Cardiac Surgery and Exploration of Tailored Criteria

Background: Cardiac surgery-associated AKI (CSA-AKI) is prevalent and its diagnosis currently adheres to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines, commonly used criteria developed for general populations. Limited evidence exists on their appropriateness and prognostic value for CSA-AKI, which exhibits unique mechanisms and clinical courses.

Aims: We aimed to assess the prognostic value of the KDIGO diagnostic criteria for CSA-AKI and explore potentially more prognostically relevant criteria for cardiac surgery.

Methods: Patients undergoing coronary artery bypass grafting surgery at a single institution were included and categorized into four groups: no AKI, AKI stage-1, AKI stage-2, and AKI stage-3, based on KDIGO guidelines. Patients of AKI-1 were further divided based on specific criteria met: absolute criteria (0.3mg/dL serum creatinine (SCr) increase over 48-hour intervals), ratio criteria (1.5-1.9 times baseline SCr), and dual criteria (meeting both criteria) AKI-1. The primary outcome was 30-day all-cause mortality.

Results: Among 20626 patients, the overall incidence of CSA-AKI was 47.4%, with rates of 44.2% for AKI-1, 2.2% for AKI-2, and 0.9% for AKI-3. The overall 30-day mortality was 0.6%. Among AKI-1, 72.4%, 3.2%, and 24.2% met the absolute criteria, ratio criteria, and dual criteria, respectively. After multivariate adjustment, AKI-2 and AKI-3 were significantly associated with increased 30-day mortality. However, neither AKI-1 nor its subcategories showed prognostic significance. Subsequent restricted cubic spline analysis identified more prognostically relevant cut-off values for AKI-1 criteria as >0.7 mg/dL SCr increase over 48-hour intervals and >1.3 times baseline SCr, respectively.

Conclusions: The current universal KDIGO diagnostic criteria may not be suitable for CSA-AKI, especially regarding cut-off values for AKI stage-1, highlighting the necessity of tailored criteria for cardiac surgery.