RENAL RESISTANCE OF DCD KIDNEYS IN HYPOTHERMIC MACHINE PERFUSION: A POTENTIAL PROGNOSTIC PARAMETER OF POST-TRANSPLANTATION GRAFT FUNCTION

Background: To overcome organ shortage, the transplantation of kidneys from donation after cardiocirculatory death (DCD) has become increasingly popular. Histological evaluation from biopsy has been widely used to predict graft function and viability, but has also been subject to limited reliability with potential procedure- associated risk. The objective of this study is to substantiate the notion that real- time renal resistance (RR) measurement during hypothermic machine perfusion (HMP) could be used as reliable and non-invasive predictive parameter in evaluation of DCD graft quality and extracorporeal membrane oxygenation ECMO donors. Methods: In Policlinico San Matteo from May 2009 until October 2022, HPM has been applied to DCD and ECMO donor kidneys. All grafts were included in the study and underwent pre-implantation biopsy for histological evaluation. Grafts assigned a Karpinski score of 4 or less were considered suitable for re-implantation. Final renal resistance parameters were obtained and the RR trend was compared with 1 month and 3 year post-operative function as well as the RR correlation with histological biopsy score for each DCD category. Results: 15 CDC II, 20 CDC III, 2 category IV and 16 ECMO-ECLS were transplanted. All grafts with a final RR trend (average perfusion time 716 min) of 0.56 and lower were considered suitable for transplant. Biopsy was confirmed and all grafts with a Karpinski score of 4 and below were allocated to recipients. A significant link was noted between 1 month serum creatinine (sCr) clearance and RR of all DCD donor kidneys. There was no clinically significant difference in cDCD and uDCD categories graft survival. Conclusions: The HMP RR value can be an alternative to histopathological score assessment for evaluation of DCD and ECMO kidneys if the acceptability threshold is reached. The present findings of this study are congruent with recent literature suggesting that carefully selected DCD kidneys offer excellent longterm clinical outcomes.