The 24‐hour normothermic machine perfusion of discarded human liver grafts

Abstract

Donor organ shortage necessitates use of less than optimal donor allografts for transplantation. The current cold storage preservation technique fails to preserve marginal donor grafts sufficiently. Evidence from large animal experiments suggests superiority of normothermic machine preservation (NMP) of liver allografts. In this study, we analyze discarded human liver grafts that underwent NMP for the extended period of 24 hours. Thirteen human liver grafts which had been discarded for transplantation were entered into this study. Perfusion was performed with an automated device using an oxygenated, sanguineous perfusion solution at normothermia. Automated control was incorporated for temperature-, flow-, and pressure-regulation as well as oxygenation. All livers were perfused for 24 hours; parameters of biochemical and synthetic liver function as well as histological parameters of liver damage were analyzed. Livers were stratified for expected viability according to the donor's medical history, procurement data, and their macroscopic appearance. Normothermic perfusion preservation of human livers for 24 hours was shown to be technically feasible. Human liver grafts, all of which had been discarded for transplantation, showed levels suggesting organ viability with respect to metabolic and synthetic liver function (to varying degrees). There was positive correlation between instantly available perfusion parameters and generally accepted predictors of posttransplant graft survival. In conclusion, NMP is feasible reliably for periods of at least 24 hours, even in highly suboptimal donor organs. Potential benefits include not only viability testing (as suggested in recent clinical implementations), but also removal of the time constraints associated with the utilization of high-risk livers, and recovery of ischemic and other preretrieval injuries (possibly by enabling therapeutic strategies during NMP). Liver Transplantation 23 207-220 2017 AASLD.

Suitability of livers for transplantation when treated by normothermic machine perfusion

“…One liver exhibited continuous bile production and lactate clearance, but the lactate level after 6 hours of NMP remained higher than 3 mmol/L. Possibly, more prolonged time on NMP might have been useful, especially as recent reports have shown the feasibility of 24‐hour normothermic perfusion …”

Machine perfusion for liver transplantation in the era of marginal organs—New kids on the block

“…This setting challenges organ retrieval logistics, as the clinical reality usually includes organ retrieval and transplantation in different hospitals and sometimes even in different countries. In preclinical studies, preservation times were extended to 24 hours by normothermic PMP . However, an extension of cold ischaemic time (CIT) before commencement of MP significantly curtailed the protective effect of NMP in a porcine DCD model .…”

Implementing an innovated preservation technology: The American Society of Transplant Surgeons’ (ASTS) Standards Committee White Paper on Ex Situ Liver Machine Perfusion

“…49 Specifically, centers need to make timely decisions to allow reallocation of the organ to other centers based on current allocation policy. Research protocols using discarded human liver allografts have demonstrated that NMP can reliably perfuse livers for periods of up to 24 hours; however, efficient allocation mandates that perfusion should be limited to much shorter periods.…”