Principles and current status of abdominal organ preservation for transplantation

Abstract

• Solid organ transplantation is an established treatment for end-stage organ failure. • Static cold storage of organs prior to transplantation has been the standard. • New machine perfusion technologies are emerging to preserve high-risk organs. • Evidence from clinical trials has demonstrated the strengths of machine perfusion. • Such technologies allow organ recovery, longer preservation and viability assessment. Solid organ transplantation provides a definitive treatment for end-stage organ failure. The clinical field has progressed rapidly since its early beginnings during the latter half of the 20th century due to advances in the understanding of immunosuppressive therapy, surgical technique and organ preservation. As result, the indications for transplantation have also expanded thereby causing an imbalance between ‘supply and demand’ of organs. There has been particular emphasis on organ preservation in order expand the donor pool. Over the past several decades, conventional organ preservation has largely relied upon static cold storage (SCS) to reduce the metabolic activity of donor organs (by cooling) and cellular swelling (by chemical composition); this has produced generally good post-transplant outcomes. This method has been advocated due to its simplicity and low costs. However, the supply of organs increasingly fails to meet the demand, resulting in the need to utilise a wider range of organs, including those that are sub-optimal. These ‘extended criteria’ donor organs are much more likely to be discarded. The 21st century has seen a resurgence of interest in novel machine perfusion technologies for the optimisation of such ‘high-risk’ organs. Several clinical trials comparing machine perfusion to SCS have reported promising outcomes particularly in the field of kidney and liver transplantation. The major benefits demonstrated include reduced organ injury, longer preservation times, improved organ utilisation, and the opportunity for organ viability testing prior to transplantation. This review will focus on the evolution of organ preservation with particular focus on the kidney and liver where considerable advances have been made in the past decade, with technology that is currently being adapted into current clinical practice.