Hypothermic Machine Perfusion vs. Static Cold Storage in Kidney Transplantation: A Retrospective Paired-Kidney Study from Latvia

<i>Background and Objectives</i>: Kidney transplantation remains the gold-standard treatment for end-stage renal disease (ESRD). For deceased donor transplantation, optimal allograft preservation represents a critical determinant of success. While static cold storage (SCS) has been the historical standard, hypothermic machine perfusion (HMP) has emerged in recent decades as a technologically advanced alternative. However, comparative data from smaller-volume centers utilizing exclusively donation after brain death (DBD) donors remain scarce. Materials and Methods: This retrospective single-center study included 94 patients who received kidney transplants from deceased DBD donors between January 2018 and December 2024. We employed a paired kidney study design where one kidney from each donor was preserved using HMP (LifePort, set at 30/20 mm Hg pressure), while the contralateral kidney was stored in SCS. Parameters compared were creatinine concentration in recipient serum after transplantation, DGF, acute rejection and hospital stay. <i>Results</i>: The HMP group had a significantly longer cold ischemia time (CIT) (18.09 ± 5.91 h, range: 6.5-34.0 h) compared to the SCS group (12.36 ± 5.18 h, range: 4.0-23.0 h; <i>p</i> < 0.005). The DGF rate was significantly lower in the HMP group (4.3%) than the SCS group (25.5%) (<i>p</i> = 0.004). HMP was also associated with a shorter mean hospitalization (11.81 vs. 15.66 days, <i>p</i> = 0.008) and superior early graft function, particularly in kidneys with CIT ≥ 18 h, which showed significantly lower serum creatinine at day 14 (124.48 vs. 164.89 µmol/L, <i>p</i> = 0.036). <i>Conclusions</i>: HMP usage in kidney transplantation decreased the possibility for DGF in DBD donors and shortened the post-op hospitalization time. It is a feasible method for kidney storage before transplantation even in a case of prolonged CIT.