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Kidney Week

Abstract: TH-PO098

Warm Ischemia Time During Pediatric Kidney Transplant Does Not Correlate With Urine AKI Biomarkers

Session Information

  • AKI: Mechanisms - I
    November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Merrill, Kyle, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
  • Kirby, Cassie L., Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
  • Chawla, Lakhmir S., VA San Diego Healthcare System, San Diego, California, United States
  • Hooper, David K., Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
  • Goldstein, Stuart, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
Background

Ischemia-reperfusion injury (IRI) is a mechanism of acute kidney injury (AKI). Like cardiopulmonary bypass, kidney transplantation is a form of controlled IRI resulting in acute tubular necrosis and possibly delayed graft function (DGF). Therefore, we sought to investigate kidney transplantation in pediatric patients as a clinical model of AKI, focusing on warm ischemia time (WIT) and novel AKI urine biomarkers.

Methods

Prospective study of patients aged 3 months to 26 years who received a kidney transplant from 7/2020 and 11/2021. Urine was collected daily for 7 days post-transplant. Biomarkers tested were neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule 1 (KIM-1), interleukin 18 (IL-18), and hepcidin. DGF was defined as receiving kidney replacement therapy within 7 days post-transplant. Wilcoxon rank sum test was used to compare cohorts. Linear regression was used to compare biomarker concentrations to WIT on post-operative days 0-2. The optimal cutoff for NGAL to predict lack of DGF was determined using negative predictive value (NPV) and a Youden’s index.

Results

4/30 patients developed DGF with a longer WIT of 55 minutes (IQR 52-57) vs. 38 minutes (IQR 32-45). Thus, we compared biomarker concentrations in patients with WIT <45 vs. ≥45 minutes. NGAL, KIM-1 and Hepcidin did not differ between cohorts. IL-18 was higher on day 1 in the ≥45-minute WIT cohort. A positive linear relationship was noted between WIT and NGAL on day 2 and a negative relationship with hepcidin on day 0. The optimal Youden’s index was 0.6 for an NGAL cutoff of 150 ng/mL on either day 0 or 1 post-transplant with a NPV of 95.7% (95% CI 80-99%).

Conclusion

We found no consistent correlation between WIT and biomarkers suggesting that AKI may be more complex than simply IRI. NGAL <150 ng/mL on post-operative day 0 or 1 correlated to a high NPV for development of DGF.