Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Sep 28, 2019; 25(36): 5559-5568
Published online Sep 28, 2019. doi: 10.3748/wjg.v25.i36.5559
Impact of small-for-size liver grafts on medium-term and long-term graft survival in living donor liver transplantation: A meta-analysis
Ka Wing Ma, Kelly Hiu Ching Wong, Albert Chi Yan Chan, Tan To Cheung, Wing Chiu Dai, James Yan Yue Fung, Wong Hoi She, Chung Mau Lo, Kenneth Siu Ho Chok
Ka Wing Ma, Wing Chiu Dai, Wong Hoi She, Department of Surgery, Queen Mary Hospital, Hong Kong, China
Kelly Hiu Ching Wong, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
Albert Chi Yan Chan, Tan To Cheung, Chung Mau Lo, Kenneth Siu Ho Chok, Department of Surgery, The University of Hong Kong, Hong Kong, China
James Yan Yue Fung, Department of Medicine, Queen Mary Hospital, Hong Kong, China
Author contributions: Ma KW, Chan ACY, Cheung TT, Fung JYY, Dai WC, and She WH contributed to study design; Ma KW contributed to manuscript writing and data analysis; Ma KW and Wong KHC contributed to the paper search; Chan ACY, Cheung TT, Fung JYY, Dai WC, and She WH contributed to proofreading; Lo CM is a senior author and conceptualized the research project; Chok KSH is the corresponding author and supervised the research project.
Conflict-of-interest statement: The authors deny any conflict of interest.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
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 Non Commercial (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: Kenneth Siu Ho Chok, FRCS (Ed), Associate Professor, Department of Surgery, The University of Hong Kong, 102 Pok Fu Lam Road, Hong Kong, China.
Telephone: +852-22553025 Fax: +852-28165284
Received: May 15, 2019
Peer-review started: May 15, 2019
First decision: June 16, 2019
Revised: June 27, 2019
Accepted: August 7, 2019
Article in press: August 7, 2019
Published online: September 28, 2019
Research background

Left side donor hepatectomy has become more popular given the paramount importance of donor safety. There is limited understanding concerning the medium-term and long-term effect of small-for-size grafts (SFSGs), which is commonly encountered in living donor liver transplantation (LDLT). This study aims to provide more evidence concerning this issue.

Research motivation

The objective is to see if SFSG imposes a negative effect on graft survival. This will help future decision making on performing left donor hepatectomy.

Research objectives

The research objective is to answer whether SFSG is associated with an inferior graft survival through meta-analysis.

Research methods

Literature comparing the survival outcomes between SFSGs and normal-for-size grafts were limited. In addition, most studies were of small sample size. Meta-analysis allows pooling of the results from these studies. This is the first meta-analysis performed on this important topic.

Research results

After extensive literature review following the preset search protocol, there were seven studies comprising of over 1800 LDLT recipients eligible to be included for meta-analysis. It was demonstrated that SFSG is associated with inferior medium-term (3-year) graft survival, but no significant effect on long-term (5-year) graft survival. This result would support the use of SFSG and potentially help promoting left shifting. However, it is beyond the capacity of this study to define what is the smallest graft size that is safe for LDLT.

Research conclusions

This is the first study trying to illustrate the effect of SFSG on graft survival using meta-analysis. With the results in this study, SFSG is associated with inferior medium-term but not long-term graft survival. Therefore, for patients who receive a SFSG, graft function should be followed more vigilantly by means of biochemical and radiological investigations. However, SFSG should not be considered an “inferior graft” when compared to normal-for-size grafts judging from the comparable long-term outcome.

Research perspectives

The result from this study seems to suggest that left lobe donor hepatectomy should be considered even if it is a SFSG to the transplant recipient for the benefit of better donor safety margin. Due to the heterogeneity of the patients in this study, whether this statement is valid in all liver transplantation indications (i.e., hepatocellular carcinoma) remains to be answered. In addition, the smallest graft size that is safe for LDLT is yet to be defined.