Establishing Ex Vivo Normothermic Machine Perfusion: A Pilot Study and A Case of Clinical Implementation

Abstract

Aim This pilot study examines ex vivo normothermic machine perfusion (EV NMP) in the evaluation of marginal donor kidneys that are at increased risk of non-utilisation. We aim to develop skill with EV NMP, intending to increase utilization of donated kidneys.

Methods In collaboration with DonateLife Victoria and with consent obtained, six donated kidneys declined for transplantation were recruited to this study and perfused with a red blood cell-based perfusate for 2 hours using EV NMP. The kidneys were evaluated using Nicholson & Hosgood’s criteria through macroscopic assessment, measurement of renal blood flow, and urine output. Perfusate samples were collected for blood gas and electrolyte analysis, and kidney biopsies were taken pre- and post- EV NMP.

Results All six kidneys showed excellent perfusion on macroscopic assessment (scoring 1), with all producing urine (median volume 480 mL) over 2 hours, and median renal blood flow measured at 196 mL/minute. The perfusate (intrinsic) creatinine level decreased significantly over the perfusion period from 151 to 82 μmol/L (p=0.02). Histopathology showed a Remuzzi score of ≤3 in all cases. Following the pilot study, a marginal donor kidney which had been declined by all transplant units, was further assessed by EV NMP and transplanted with satisfactory outcomes.

Conclusion In this pilot study, all 6 non-utilised kidneys demonstrated satisfactory perfusion and early function, with no instances of failed perfusion. This pilot study has established the necessary skills and processes for EV NMP of kidneys at Austin Health and paves a way for clinical implementation.

Impact This pilot study has successfully paved the way for clinical translation and to increase utilisation of donated kidneys. In addition, establishment of EV NMP provides a platform for future research to improve transplant outcomes.