Split-liver transplantation in the high-MELD adult patient: are we being too cautious?

Current Understanding of Marginal Grafts in Liver Transplantation

End-stage liver disease (ESLD), stemming from a spectrum of chronic liver pathologies including chronic liver failure, acute cirrhosis decompensation and hepatocellular carcinoma, imposes a significant global healthcare burden. Liver transplantation (LT) remains the only treatment for ESLD. However, the escalating mortality on transplant waitlists has prompted the utilization of marginal liver grafts in LT procedures. These grafts primarily encompass elderly livers, steatotic livers, livers from donation after circulatory death, split livers and those infected with the hepatitis virus. While the expansion of the donor pool offers promise, it also introduces concomitant risks. These encompass graft failure, biliary and cardiovascular complications, the recurrence of liver disease and reduced patient and graft survival. Consequently, various established strategies, ranging from improved donor-recipient matching to surgical interventions, have emerged to mitigate these risks. This article undertakes a comprehensive assessment of the current landscape, evaluating the viability of diverse marginal liver grafts. Additionally, it synthesizes approaches aimed at enhancing the quality of such marginal liver grafts. The overarching objective is to augment the donor pool and ameliorate the risk factors associated with the shortage of liver grafts.

Full-Right Full-Left Split Liver Transplantation for Two Adult Recipients: A Single-Center Experience in China

BACKGROUND

The most effective treatment for end-stage liver diseases is liver transplantation, which is impeded by the shortage of donor livers. Split liver transplantation (SLT) is important for addressing the donor liver shortage. However, full-right full-left SLT for two adult recipients is globally rarely conducted. This study aimed to investigate the clinical outcomes of this technique.

METHODS

We retrospectively analyzed the clinical data of 22 recipients who underwent full-right full-left SLT at Shulan (Hangzhou) Hospital between January, 2021 and September, 2022. The graft-to-recipient weight ratio (GRWR), cold ischemia time, operation time, length of the anhepatic phase, intraoperative blood loss, and red blood cell transfusion amount were all analyzed. The differences in liver function recovery after transplantation were compared between the left and right hemiliver groups. The postoperative complications and prognosis of the recipients were also analyzed.

RESULTS

The livers of 11 donors were transplanted into 22 adult recipients. The GRWR ranged from 1.16-1.65%, the cold ischemia time was 282.86 ± 134.87 min, the operation time was 371.32 ± 75.36 min, the anhepatic phase lasted 60.73 ± 19.00 min, the intraoperative blood loss was 759.09 ± 316.84 mL, and the red blood cell transfusion amount was 695.45 ± 393.67 mL. No significant difference in the levels of liver function markers, total bilirubin, aspartate aminotransferase, or alanine aminotransferase between left and right hemiliver groups at 1, 3, 5, 7, 14, and 28 d postoperatively was observed (both p > 0.05). One recipient developed bile leakage 10 d after transplantation, which improved with endoscopic retrograde cholangiopancreatography-guided nasobiliary drainage and stent placement. Another developed portal vein thrombosis 12 d after transplantation and underwent portal vein thrombectomy and stenting to restore portal vein blood flow. A color Doppler ultrasound performed 2 d after transplantation revealed hepatic artery thrombosis in one patient, and thrombolytic therapy was administered to restore hepatic artery blood flow. The liver function of other patients recovered quickly after transplantation.

CONCLUSIONS

Full-right full-left SLT for two adult patients is an efficient way to increase the donor pool. It is safe and feasible with careful donor and recipient selection. Transplant hospitals with highly experienced surgeons in SLT are recommended to promote using full-right full-left SLT for two adult recipients.

Application Effectiveness of Segment IV Portal Vein Reconstruction for Early Postoperative Liver Function Recovery in Split Liver Transplantation

The objective of this study was to investigate the significance of portal vein reconstruction in segment IV of the liver on early postoperative liver function recovery in split liver transplantation. The clinical data of patients of right trilobe split liver transplantation in our center were analyzed and divided into two groups, including a group without portal vein reconstruction and a group with portal vein reconstruction. Clinical data of alanine aminotransferase (ALT), aspartate transaminase (AST), albumin (ALB), creatinine (Cr), total bilirubin (TB), alkaline phosphatase (ALP), gamma-glutamyl Transferase (GGT), lactic acid (Lac), and international normalized ratio (INR) levels were analyzed. The technique of segment IV portal vein reconstruction is beneficial to the early postoperative recovery of liver function. Statistically, there was no significant effect of portal vein reconstruction in the IV segment of the liver on the recovery of liver function within 1 week after split liver transplantation. There was no significant difference in survival rate between the control group and reconstruction group over the 6 months follow-up period after surgery.

Is it safe to expand the indications for split liver transplantation in adults? A single-centre analysis of 155 in-situ splits

INTRODUCTION

Split liver transplantation (SLT) enables two recipients to be transplanted using a single donor liver; typically, an adult and a child. Despite equivalent long-term outcomes to whole grafts in selected adults, the use of these grafts in high-risk adult recipients with high model for end-stage liver disease (MELD) scores (≥30), a poor pre-transplant clinical status (ICU or hospital-bound), acute liver failure or retransplantation remains controversial.

METHODS

We retrospectively analysed all deceased donor adult liver transplants performed between July 2002 and November 2019 at a single high-volume centre and performed a propensity score-matched analysis. A subgroup analysis was performed to assess utility of these grafts for high-risk recipients.

RESULTS

A total of 1090 adult liver transplants were performed, including 155 SLT (14%). Graft survival at 1-, 3- and 5-years were comparable between recipients of split and whole liver grafts (82%, 79% and 74% vs 86%, 81% and 77% respectively, log rank p = 0.537), as was patient survival at 1-, 3- and 5-years. Recipients of split grafts were more likely to have biliary complications and hepatic artery thrombosis, but equivalent long-term survival. Recipients with high MELD scores or a poor pre-transplant clinical status had similar patient and graft survival and complication profiles irrespective of whether they received split or whole grafts.

CONCLUSIONS

SLT is an important method for addressing donor shortages and provides comparable long-term outcomes in adult recipients despite an increase in short-term complications. SLT use in high-risk recipients should be considered to allow for sickest-first allocation policies. This article is protected by copyright. All rights reserved.

Are split liver grafts a suitable option in high-risk liver transplant recipients?

PURPOSE OF REVIEW

To assess the outcomes of split liver transplantation (SLT) in adults and children and evaluate its role in high-risk recipients with a high model for end-stage liver disease (MELD) score, an urgent indication or requiring retransplantation.

RECENT FINDINGS

Split liver grafts in general have equivalent long-term survival outcomes to whole grafts despite an increase in biliary complications. Recent success and technical advances have encouraged use of these grafts in high-risk recipients. Split liver grafts can be used successfully in recipients with a high MELD score if there is adequate weight-matching. There are mixed results in urgent indication recipients and for retransplantation such that use in this group of patients remains controversial.

SUMMARY

SLT addresses donor shortages by facilitating the transplant of two recipients from the same donor liver. By using careful donor and recipient selection criteria, SLT can achieve equivalent long-term outcomes to whole grafts. These grafts have been used successfully in recipients with a high MELD score, but should be used selectively in urgent indication recipients and for retransplantation.

A review of split liver transplantation with full right/left hemi-liver grafts for 2 adult recipients

Liver transplantation has become a routine operation in many transplantation centers worldwide. However, liver graft availability fails to meet patient demands. Split liver transplantation (SPLT), which divides a deceased donor liver into 2 partial liver grafts, is a promising strategy for increasing graft availability for transplantation and ameliorating organ shortage to a certain degree. However, the transplantation community has not yet reached a consensus on SPLT because of the variable results. Specifically, SPLT for 2 adult recipients using full right/left hemi-liver grafts is clinically more challenging in terms of surgical technique and potential postoperative complications. Therefore, this review summarizes the current status of SPLT, focusing on the transplantation of adult recipients. Furthermore, the initiation of the SPLT program, donor allocation, surgical aspects, recipient outcomes, and obstacles to developing this procedure will be thoroughly discussed. This information might help provide an optimal strategy for implementing SPLT for 2 adult recipients among current transplantation societies. Meanwhile, potential obstacles to SPLT might be overcome in the near future with growing knowledge, experience, and refinement of surgical techniques. Ultimately, the widespread diffusion of SPLT may increase graft availability and mitigate organ donation shortages.

The Surge in Deceased Liver Donors Due to the Opioid Epidemic: Is It Time to Split the Difference?

BACKGROUND

This study aimed to compare trends in use of drug overdose (DO) donors in adult versus pediatric liver transplants and the utilization of split liver transplantation in this donor population.

METHODS

The United Network for Organ Sharing database was reviewed for deceased donor liver transplants from March 2002 to December 2017. Recipients were categorized by donor mechanism of death. Donor splitting criteria was defined as age <40 y, single vasopressor or less, transaminases no >3 times the normal limit, and body mass index ≤ 28 kg/m2.

RESULTS

Adult liver transplants from DO donors increased from 2% in 2002 to 15% in 2017, while pediatric liver transplants from DO donors only increased from <1% to 3% in the same time. While 28% of DO donors met splitting criteria, only 3% of those meeting splitting criteria were used as a split graft. Both pediatric and adult recipients of DO donor livers achieved excellent patient and graft survival.

CONCLUSIONS

DO donors are underutilized in pediatric liver transplantation. Increased splitting of DO donor livers could significantly decrease, if not eliminate, the pediatric liver waiting list.

Liberal Use of Interposition Grafts for Arterial Reconstruction Is Safe and Effective in Adult Split Liver Transplantation

Background.

Split liver transplantation (SLT) addresses donor shortages by providing 2 partial grafts from a single donor liver. Arterial reconstruction using an interposition graft facilitates the use of split grafts with difficult recipient anatomy. Its use, however, remains controversial because of a reported increased risk of complications.

Methods.

A retrospective review of the prospectively maintained Australian National Liver Transplantation Unit database was performed. Donor, recipient, operative, and complications data for adults receiving an SLT between July 2002 and November 2019 were extracted.

Results.

Arterial reconstruction required an interposition graft in 46 of 155 patients. Overall graft and patient survival were not significantly different between the groups with 1-, 3-, and 5-y graft survivals of 82%, 77%, and 69% for those with interposition grafts and 86%, 79%, and 77% for those without interposition grafts, respectively (P = 0.499). There were more cut liver bile leaks in the interposition graft group (26% versus 9%, P = 0.004), but otherwise, no significant differences in the rate of biliary complications (39% versus 29% P = 0.200), hepatic artery thrombosis (7% versus 10%, P = 0.545), or hepatic artery stenosis (13% versus 10%, P = 0.518).

Conclusions.

Liberal use of interposition grafts for arterial reconstruction in SLT is safe and does not result in increased complications.

Outcomes of hemi- versus whole liver transplantation in patients from mainland china with high model for end-stage liver disease scores: a matched analysis

Background

Adult hemiliver transplantation (AHLT) is an important approach given the current shortage of donor livers. However, the suitability of AHLT versus adult whole liver transplantation (AWLT) for recipients with high Model for End-Stage Liver Disease (MELD) scores remains controversial.

Methods

We divided patients undergoing AHLT and AWLT into subgroups according to their MELD scores (≥ 30: AHLT, n = 35; AWLT, n = 88; and < 30: AHLT, n = 323; AWLT, n = 323). Patients were matched by demographic data and perioperative conditions according to propensity scores. A cut-off value of 30 for MELD scores was determined by comparing the overall survival data of 735 cases of nontumor liver transplantation.

Results

Among patients with an MELD score ≥ 30 and < 30, AHLT was found to be associated with increased warm ischemia time, operative time, hospitalization time, and intraoperative blood loss compared with AWLT (P < 0.05). In the MELD ≥ 30 group, although the 5-year survival rate was significantly higher for AWLT than for AHLT (P = 0.037), there was no significant difference between AWLT and AHLT in the MELD < 30 group (P = 0.832); however, we did not observe a significant increase in specific complications following AHLT among patients with a high MELD score (≥ 30). Among these patients, the incidence of complications classified as Clavien-Dindo grade III or above was significantly higher in patients undergoing AHLT than in those undergoing AWLT (25.7% vs. 11.4%, P = 0.047). For the MELD < 30 group, there was no significant difference in the incidence of complications classified as Clavien-Dindo grade III or above for patients undergoing AHLT or AWLT.

Conclusion

In patients with an MELD score < 30, AHLT can achieve rates of mortality and overall survival comparable to AWLT. In those with an MELD score ≥ 30, the prognosis and incidence of complications classified as Clavien-Dindo III or above are significantly worse for AHLT than for AWLT; therefore, we may need to be more cautious regarding the conclusion that patients with a high MELD score can safely undergo AHLT.

Is there an ethical obligation to split every donor liver? Scarce resources, medical factors, and ethical reasoning

SLT has the potential to counter the worldwide shortage of donor organs. Although the preferred recipients of SLT are usually pediatric patients, a more stringent ethical argument than the fundamental prioritization of children is to demonstrate that SLT of deceased donor organs could increase access to this potentially lifesaving resource for all patients, including children. Several empirical studies show that SLT also makes it possible to achieve similar outcomes to WLT in adults if several factors are observed. In general, it can be regarded as ethically permissible to insist on splitting a donor liver if, in an individual case, SLT is expected to have a similar outcome to that of WLT. The question is therefore no longer whether, but under what conditions SLT is able to achieve similar results to WLT. One of the main challenges of the current debate is the restricted comparability of the available data. We therefore have an ethical obligation to improve the available empirical data by implementing prospective clinical studies, SLT programs, and national registries. The introduction of 2 modes of allocation-one for patients willing to accept both SLT and WLT, and a second for patients only willing to accept WLT-would help to resolve the issue of patient autonomy in the case of mandatory splitting policy.

The Current State of Liver Transplantation in the United States: Perspective From American Society of Transplant Surgeons (ASTS) Scientific Studies Committee and Endorsed by ASTS Council

This article is a review of the salient points and a future prospective based on the 2014 Organ Procurement and Transplantation Network (OPTN)/Scientific Registry of Transplant Recipients (SRTR) liver donation and transplantation data report recently published by the American Journal of Transplantation. Emphasis of our commentary and interpretation is placed on data relating to waitlist dynamics, organ utilization rates, the impact of recent advances in the treatment of hepatitis C, and the increases in end-stage renal disease among liver transplant candidates. Finally, we share our vision on potential areas of innovation that are likely to significantly improve the field of liver transplantation in the near future.

Long-term results after adult ex situ split liver transplantation since its introduction in 1987

BACKGROUND

Split liver transplantation is still discussed controversially. Utilization of split liver grafts has been declining since a change of allocation rules for the second graft abolished incentives for German centres to perform ex situ splits. We therefore analysed our long-term experiences with the first ex situ split liver transplant series worldwide.

METHODS

A total of 131 consecutive adult ex situ split liver transplants (01.12.1987-31.12.2010) were analysed retrospectively.

RESULTS

Thirty-day mortality rates and 1- and 3-year patient survival rates were 13, 76.3, and 66.4 %, respectively. One- and three-year graft survival rates were 63.4 and 54.2 %, respectively. The observed 10-year survival rate was 40.6 %. Continuous improvement of survival from era 1 to 3 was observed (each era: 8 years), indicating a learning curve over 24 years of experience. Patient and graft survival were not influenced by different combinations of transplanted segments or types of biliary reconstruction (p > 0.05; Cox regression). Patients transplanted for primary sclerosing cholangitis had better survival (p = 0.021; log-rank), whereas all other indications including acute liver failure (13.6 %), acute and chronic graft failure (9.1 %) had no significant influence on survival (p > 0.05; log-rank). Biliary complications (27.4 %) had no significant influence on patient or graft survival (p > 0.05; log-rank). Hepatic artery thrombosis (13.2 %) had a significant influence on graft survival but not on patient survival (p = 0.002, >0.05, respectively; log-rank).

CONCLUSIONS

Split liver transplantation can be used safely and appears to be an underutilized resource that may benefit from liberal allocation of the second graft.

Split liver transplantation using Hemiliver graft in the MELD era: a single center experience in the United States

Under the "sickest first" Model for End-Stage Liver Disease (MELD) allocation, livers amenable to splitting are most often allocated to patients unsuitable for split liver transplantation (SLT). Our experience with SLT using hemilivers was reviewed. From April 2004 to June 2012, we used 25 lobar grafts (10 left lobes and 15 right lobes) for adult-sized recipients. Twelve recipients were transplanted with primary offers, and 13 were transplanted with leftover grafts. Six grafts were shared with other centers. The data were compared with matched whole liver grafts (n = 121). In 92% of donors, the livers were split in situ. Hemiliver recipients with severe portal hypertension had a greater graft-to-recipient weight ratio than those without severe portal hypertension (1.96% vs. 1.40%, p < 0.05). Hemiliver recipients experienced biliary complications more frequently (32.0% vs. 10.7%, p = 0.01); however, the 5-year graft survival for hemilivers was comparable to whole livers (80.0% vs. 81.5%, p = 0.43). The secondary recipients with leftover grafts did not have increased incidences of graft failure (p = 0.99) or surgical complications (p = 0.43) compared to the primary recipients. In conclusion, while routine application is still controversial due to various challenges, hemiliver SLT can achieve excellent outcomes under the MELD allocation.

Trends in liver transplantation 2011

This review will highlight some of the important recent trends in liver transplantation. When possible, we will compare and contrast these trends across various regions of the world, in an effort to improve global consensus and better recognition of emerging data.

Experience Since MELD Implementation: How Does the New System Deliver?

Because of increasing waiting-list mortality, the MELD (Model for End-Stage Liver Disease) allocation system was implemented within most countries of the Eurotransplant area on December 16, 2006. Five years have now passed, and we review in this paper the effects of the MELD-based allocation upon the waiting list for liver transplantation, on peri-operative management and on postoperative outcome. Giving priority to sicker patients on the waiting list has resulted in a significant increase in mean MELD score at the time of organ allocation. Consequently, there has also been a significant reduction in waiting-list mortality. However, in Germany a worsening in postoperative outcome, mainly in the group of high-MELD recipients (≥30 points), has been reported. This paper presents comprehensive results following liver transplantation within the MELD era. Especially for the group of high-risk recipients, risk factors for impaired survival are presented and discussed.

Impact of the MELD allocation after its implementation in liver transplantation

OBJECTIVE

On 16 December 2006, most Eurotransplant countries changed waiting time oriented liver allocation policy to the urgency oriented Model for End-stage Liver Disease (MELD) system. There are limited data on the effects of this policy change within the Eurotransplant community.

PATIENTS AND METHODS

A total of 154 patients who had undergone deceased donor liver transplantation (LT) were retrospectively analyzed in three time periods: period A (1-year pre-MELD, n = 42) versus period B (1-year post-MELD, n = 52) versus period C (2 years after MELD implementation, n = 60).

RESULTS

The median MELD score at the time of LT increased from 16.3 points in period A to 22.4 and 20.4 in periods B and C, respectively (p = 0.007). Waitlist mortality decreased from 18.4% in period A to 10.4% and 9.4% in periods B and C, respectively (p = 0.015). Three-month mortality did not change significantly (10% each for periods A, B and C). One-year survival was 84% for the MELD 6-19 group compared with 81% in the MELD 20-29 group and 74% in the MELD ≥30 group (p = 0.823). Analyzing MELD score and previously described prognostic scores [i.e. survival after liver transplantation (SALT) score and donor-MELD (D-MELD) score] with regard to 1-year survival, only a high risk SALT score was predictive (p = 0.038). In our center, 2 years after implementation of the MELD system, waitlist mortality decreased, while 90-day mortality did not change significantly.

CONCLUSION

Up to now, only the SALT score proved to be of prognostic relevance post-transplant.