Time as a Therapeutic Ally: The Promise of Long-Term Solid Organ and Tissue Perfusion

Rapid advances in tissue preservation and the growing adoption of machine perfusion have fundamentally reshaped solid-organ and tissue transplantation in recent years. Multiple short-term perfusion devices have received regulatory approval and are increasingly used in clinical practice to preserve grafts for several hours, improving allograft assessment. The boundaries of dynamic tissue preservation have been pushed even further in research settings, where grafts have been reliably perfused for multiple days. The extended time of long-term machine perfusion opens a new therapeutic window for interventions, allowing for reconditioning and even tissue repair of injured and diseased grafts. The increasing global organ shortage makes these approaches particularly attractive to recover additional allografts for safe transplantation. In this review, we highlight current clinical practice for ex situ perfused allografts, multi-day perfusions in research settings, and potential therapeutic benefits of long-term perfusion with a focus on hearts, livers, lungs and vascularized composite allografts.