Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Sep 14, 2021; 27(34): 5727-5736
Published online Sep 14, 2021. doi: 10.3748/wjg.v27.i34.5727
Machine perfusion of the liver: Putting the puzzle pieces together
Yuri L Boteon, Paulo N Martins, Paolo Muiesan, Andrea Schlegel
Yuri L Boteon, Liver Unit, Hospital Israelita Albert Einstein, São Paulo 05652-900, Brazil
Yuri L Boteon, Instituto Israelita de Ensino e Pesquisa Albert Einstein, Faculdade Israelita de Ciências da Saúde Albert Einstein, São Paulo 05652-900, Brazil
Paulo N Martins, Department of Surgery, Transplant Division, University of Massachusetts Medical School, Worcester, MA 01655, United States
Paolo Muiesan, Andrea Schlegel, Hepatobiliary Unit, Careggi University Hospital, University of Florence, Florence 50134, Italy
Andrea Schlegel, Department of Visceral Surgery and Transplantation, University Hospital Zurich, Swiss HPB and Transplant Center, Zurich 8091, Switzerland
Author contributions: Boteon YL designed this study; Boteon YL, Martins PN, Muiesan P and Schlegel A performed the literature review and analysis; Boteon YL drafted the manuscript; Boteon YL, Martins PN, Muiesan P, and Schlegel A reviewed the manuscript critically; All authors contributed to editing and approved the final manuscript version.
Conflict-of-interest statement: The authors have no conflicts of interest to disclose.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Yuri L Boteon, MD, PhD, Doctor, Professor, Surgeon, Liver Unit, Hospital Israelita Albert Einstein, Jardim Leonor, São Paulo 05652-900, São Paulo, Brazil.
Received: March 2, 2021
Peer-review started: March 2, 2021
First decision: April 17, 2021
Revised: May 3, 2021
Accepted: July 21, 2021
Article in press: July 21, 2021
Published online: September 14, 2021

The realm of extended criteria liver transplantation created the 'adjacent possible' for dynamic organ preservation. Machine perfusion of the liver greatly expanded donor organ preservation possibilities, reaching before unattainable goals, including the mitigation of ischemia-reperfusion injury, viability assessment, and organ reconditioning prior to transplantation. However, current scientific evidence lacks uniformity between studies, perfusion protocols, and acceptance criteria. Construction of collaborative research networks for sharing knowledge should, therefore, enable the development of high-level evidence and guidelines for machine perfusion utilization, including donor acceptance criteria. Finally, this approach shall guarantee conditions for further progress to occur.

Keywords: Machine perfusion of the liver, Liver transplantation, Organ donation, Extended criteria donors, Liver preservation, Clinical trials

Core Tip: The frequent use of extended criteria donor organs unveiled the limits of static cold storage and created the conditions for the renewed interest in dynamic organ preservation. Indeed, several studies have suggested the superiority of this method over static cold storage for these high-risk donors. However, controversy still exists between different machine perfusion modalities and even amongst studies employing the same method, compromising the strength of the available evidence. With the currently fragmented efforts, the development of collaborative networks will produce collective outcomes that will expand the boundaries of current knowledge.