Beyond the Score Study: Retrospective Analysis of Single-Graft Kidney Transplant with Karpinski Score 4 Versus Score 5 Grafts

<i>Background and Objectives</i>: Considering the growing shortage of grafts available for kidney transplantation (KT) due to the increase in the number of end-stage renal disease patients, it is essential to utilize all transplantation options. The Karpinski score is a histological scoring system utilized for the evaluation of pre-implantation kidney biopsies from deceased donors. In contrast with Remuzzi Criteria, there has recently been a tendency to perform single KT using grafts with a Karpinski score of 4 or 5. This strategy allows two score 4 or 5 grafts to be used for two different recipients instead of a double-graft KT on one patient. The aim of this study was to analyze the outcomes of single-graft KT with a score of 4 versus 5, and to investigate possible correlations with the clinical characteristics of donors and recipients. <i>Materials and Methods</i>: Retrospective single-centre analysis of 100 KTs performed with a single Karpinski score 4 or 5 graft between January 2014 and December 2022. <i>Results</i>: Grafts with a Karpinski score of 5 harvested from donors older than 70 years of age had a statistically significant (<i>p</i> = 0.014) worse 5-year survival rate (50.0 +/- 18.6%) compared to younger donors (100% for score 5 grafts from donors aged 31-60, and 100% for score 5 grafts from donors aged 61-70). Conversely, donor's age did not significantly affect the survival of score 4 grafts. <i>Conclusions</i>: The results suggest that a single-graft KT with a Karpinski score 5 graft may be a viable procedure with favourable outcomes. However, for Karpinski score 5 grafts, the use of an older donor beyond the age of 70 seems to be a significant negative factor for the long-term outcome. In such cases, a double KT would potentially be the optimal approach.