Normothermic machine perfusion versus static cold storage for liver transplantation: a systematic review and meta-analysis.

PURPOSE: To compare the effectiveness of normothermic machine perfusion (NMP) with static cold storage (SCS) in preserving transplantable livers, focusing on early postoperative complications. METHODS: A PRISMA 2020-compliant search of PubMed, Embase, Scopus, Cochrane Library and Web of Science identified comparative studies of NMP versus SCS. Five studies met the criteria (two randomized controlled trials, and three observational cohorts; 630 recipients). Random-effects meta-analysis was performed in RStudio, reporting risk ratio (RR), 95% confidence interval (95%CI), p-value and heterogeneity (I2). RESULTS: NMP significantly lowered the incidence of composite early postoperative complications versus SCS (RR = 0.60; 95%CI 0.47-0.75; p < 0.0001), corresponding to a 40% relative risk reduction. Between-study heterogeneity was negligible (I2 = 0 %). Subgroup analyses revealed no significant effect modification by study design (p = 0.75), donation after circulatory death proportion (p = 0.91), preservation duration (p = 0.51), donor age (p = 0.59) or perfusion technique (p = 0.37). CONCLUSION: NMP demonstrates clinically superior graft preservation compared with SCS, consistently reducing early complications after liver transplantation. Adoption of NMP may expand the use of marginal organs and improve post-transplant outcomes.