Machine Perfusion in Renal Transplantation: A Comprehensive Review of Viability Assessment

Machine perfusion (MP) in renal transplantation has revolutionized organ preservation, offering advantages over static cold storage methods. This approach involves the continuous circulation of a preservation solution through the renal vascular system, maintaining metabolism and reducing ischemia-reperfusion injury. MP systems include both hypothermic and normothermic variants. Hypothermic MP operates at low temperatures (1°C–10°C), reducing metabolic demands while providing nutrients and oxygen. Normothermic MP maintains organs at physiological temperatures (35°C–37°C), allowing for functional assessment and therapeutic interventions. Kidney viability assessment during MP incorporates several parameters and biomarkers. Perfusion dynamics, including renal blood flow, vascular resistance, and pressure gradient, provides insights into organ function. Biochemical markers such as lactate dehydrogenase, aspartate aminotransferase, and neutrophil gelatinase-associated lipocalin indicate cellular damage and graft function. Real-time imaging and metabolomic profiling enhance organ quality evaluation and outcome predictions. This review highlights advances in graft viability assessment and MP technologies, which improve marginal donor organ utilization and expand the donor kidney pool for transplantation.