Kidneys From Older Donors After Circulatory Death Plus Normothermic Regional Perfusion or Standard Rapid Retrieval Have Comparable Function in the Context of Ex Situ Oxygenated Hypothermic Machine Perfusion

Background. With growing transplant waiting lists, more extended criteria donor organs are being accepted, requiring optimization of the organs to increase utilization. Abdominal normothermic regional perfusion (aNRP) benefits the outcomes of transplanted livers and pancreatic islets, but its effects on donor kidneys subsequently preserved with (oxygenated) hypothermic machine perfusion (HMPO 2 ) remain to be determined. This study examines the function and survival of an aNRP-preserved controlled donation after circulatory death (cDCD) kidneys followed by HMPO 2 . Methods. From October 2018 until June 2023, we evaluated all ≥50 y cDCD kidneys retrieved using aNRP during a pilot implementation project and compared posttransplant outcomes of these donor kidneys to those of cDCD kidneys retrieved by standard rapid retrieval during the same period. All kidneys received HMPO 2 as standard preservation. This study primarily compared estimated glomerular filtration rate (Chronic Kidney Disease Epidemiology Collaboration), 1 y graft and recipient survival. Results. Data of 70 aNRP-preserved kidneys were compared with a control group of 124 kidneys. One year estimated glomerular filtration rate was comparable between groups (40.4 mL/min/1.73 m 2 [29.3-52.3] versus 40.0 mL/min/1.73 m 2 [28.1-48.1]; P = 0.5) as well as graft and recipient survival at 1 y (81.4% versus 83.1%; hazard ratio, 1.1; 95% confidence interval [CI], 0.6-2.3; P = 0.63; 88.6% versus 88.7%, hazard ratio, 1.0; 95% CI, 0.4-2.4; P = 0.99, respectively). Primary nonfunction and delayed graft function were not significantly different (odds ratio, 1.3; 95% CI, 0.4-4.2; P = 0.68; odds ratio, 1.3; 95% CI, 0.7-2.5; P = 0.39). Conclusions. This study demonstrates that aNRP-preserved kidneys from cDCD donors aged 50 y and older had comparable outcomes to kidneys retrieved with standard rapid retrieval, in the context of HMPO 2 as a standard ex situ preservation technique. This differs from earlier studies showing improved results of aNRP in the context of cold storage without standard machine perfusion. With aNRP gaining interest because of its value for liver and pancreatic islet transplantation, a prospective randomized study should be performed to further analyze the benefit of continuous kidney HMP(O 2 ) after aNRP.