Kidney Machine Preservation: State of the Art

Purpose of the Review Machine perfusion has become an important asset in solid organ transplantation to improve the constant organ shortage. This review summarizes advances in machine perfusion of kidney grafts over the last 3 years. Recent Findings Because of the severe organ shortage, more and more marginal grafts are being accepted for transplantation. In an attempt to decrease preservation injury and better assess grafts before transplantation, research studies have focused their attention on ex vivo machine perfusion. Hypothermic machine perfusion has been used in a clinical setting for years and has proven to be superior to cold storage. Recently, novel technologies, such as normothermic ex vivo machine perfusion, controlled oxygenated rewarming, and normothermic in situ perfusion, have triggered interest to decrease preservation injury and improve the outcome of marginal grafts. Keeping grafts metabolically active allows for a better assessment, reconditioning, and organ repair. Preclinical results suggest that normothermic perfusion is superior to hypothermic perfusion and static cold storage. Normothermic ex vivo perfusion has been translated into clinical trials, with encouraging first results. Currently, there is no consensus regarding a protocol for warm perfusion. Normothermic regional perfusion is used to recirculate blood in situ to restore the changes after warm ischemic injury. First results are promising, but further assessments are needed to explore the potential of this novel approach. Ex vivo machine perfusion is a superior preservation method compared with cold storage. Optimal perfusion solution, temperature, and machine technology are still controversial. Graft assessment and repair are the central research focuses at the moment.