Donor and recipient selection leads to good patient and graft outcomes for right lobe split transplantation versus whole graft liver transplantation in adult recipients

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.

Addressing the challenges of split liver transplantation through technical advances. A systematic review

BACKGROUND

Split liver transplantation addresses donor shortages by facilitating the transplant of two recipients using one donor liver. Some still consider these grafts inferior due to prolonged cold ischaemia time and at times difficult vascular reconstruction. Techniques such as in-situ splitting, machine perfusion and interposition grafts may address these challenges and thereby address these concerns. The aim of this review is to assess these technical advances in split liver transplantation, their utility and outcomes.

METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Keywords included 'split liver transplantation', 'arterial reconstruction', and 'machine perfusion'. Data found was synthesised into sections including: methods of splitting, full-left full-right splitting, donor cholangiography, machine perfusion and arterial reconstruction.

RESULTS

A total of 78 articles met inclusion criteria after screening of 151 eligible articles. These were subdivided into the following categories: in-situ (25), ex-vivo (25), full-left full-right splitting (15), donor cholangiography (2), machine perfusion (6), and arterial reconstruction (5). The in-situ splitting technique reduces the cold ischaemia time compared to the ex-vivo technique which may improve graft quality and liver splitting during normothermic machine perfusion is a novel technique with the potential to incorporate the best aspects of both techniques. Interposition grafts are often required during split liver transplantation but have an increased risk of hepatic artery thrombosis.

CONCLUSION

Advancements in technique have allowed many of the unique challenges of split liver transplantation to be overcome. Overall, this supports the use of split liver transplantation in broader and riskier settings and we advocate for liver transplant surgeons to not hesitate in using these grafts liberally and expanding their recipient selection criteria.

Considering extended right lobe grafts as major extended donor criteria in liver transplantation is justified

The outcomes of split-liver transplantation are controversial. This study compared outcomes and morbidity after extended right lobe liver transplantation (ERLT) and whole liver transplantation (WLT) in adults. MEDLINE and Web of Science databases were searched systematically and unrestrictedly for studies on ERLT and its impact on graft and patient survival, and postoperative complications. Graft loss and patient mortality odds ratios (OR) and 95% confidence intervals (CI) were assessed by meta-analyses using Mantel-Haenszel tests with a random-effects model. Vascular and biliary complications, primary nonfunction, 3-month, 1-, and 3-year graft and patient survival, and retransplantation after ERLT and WLT were analyzed. The literature search yielded 10 594 articles. After exclusion, 22 studies (n = 75 799 adult transplant patients) were included in the analysis. ERLT was associated with lower 3-month (OR = 1.43, 95% CI = 1.09-1.89, P = 0.01), 1-year (OR = 1.46, 95% CI = 1.08-1.97, P = 0.01), and 3-year (OR = 1.37, 95% CI = 1.01-1.84, P = 0.04) graft survival. WL grafts were less associated with retransplantation (OR = 0.57; 95% CI = 0.41-0.80; P < 0.01), vascular complications (OR = 0.53, 95% CI = 0.38-0.74, P < 0.01) and biliary complications (OR = 0.67; 95% CI = 0.47-0.95; P = 0.03). Considering ERLT as major Extended Donor Criteria is justified because ERL grafts are associated with vasculobiliary complications and the need for retransplantation, and have a negative influence on graft survival.

Right lobe split liver graft versus whole liver transplantation: A systematic review by updated traditional and cumulative meta-analysis

INTRODUCTION

Advancements in surgical techniques and experience of donor-recipient pairing has led to a wider use of right split liver grafts in adults. An update meta-analysis was conducted to compare right split liver graft (RSLG) and whole liver transplantation (WLT) using traditional and cumulative approaches.

METHODS

Databases were searched for relevant articles over the previous 20 years (MEDLINE, Embase, Cochrane Library, and Google Scholar). Meta-analyses were performed using both fixed and random effects models. Patient and graft survival were obtained using the inverse variance hazard ratio method.

RESULTS

Donors were significantly younger in the RSLG group than in the WLT group (MD = -12.06 [-16.29 to -7.83]; P < .001). In addition, the model for end-stage liver disease (MELD) score was significantly lower in the RSLG group than in the WLT group (MD = -2.45 [-4.61 to -.28]; P = .03). However, cold ischaemia time was significantly longer by 1 h in the RSLG group than in the WLT group (MD = 57 [20.63-92.73]; P = .002). Overall biliary, vascular, and outflow tract complications and hepatic artery thrombosis were significantly lower in the WLT group than in the RSLG group (odds ratio [OR] = 1.75 [1.35-2.27], P < .001; OR = 1.91 [1.37-2.65], P = .006; Peto OR = 1.83 [1.19-2.82], P = .006; and Peto OR = 2.07 [1.39-3.10], P = .004, respectively). However, no difference in patient and graft survival was noted between the two cohorts.

CONCLUSIONS

Although the RSLG group had a higher postoperative complication rate than the WLT group, equal patient and graft survival benefits were observed.

A matched pair analysis of multicenter longterm follow-up after split-liver transplantation with extended right grafts

Split-liver transplantation has been proposed as an alternative to whole liver (WL) transplantation to expand the donor pool, but studies comparing adult longterm outcomes between the 2 methods are conflicting and limited. This is the first Italian multicenter study that retrospectively analyzed 119 matched-pair recipients of whole and extended right grafts (ERGs) for longterm survival outcomes. In the overall population, WL recipients showed higher patient survival at 1 (93% versus 73%), 5 (87% versus 65%), and 10 years (83% versus 60%) after transplantation compared with split-liver recipients (P < 0.001); graft survivals of WL recipients were also superior at 1 (90% versus 76%), 5 (84% versus 57%), and 10 years (81% versus 52%) posttransplant (P < 0.001). However, among the 81 matched pairs that survived the first posttransplant year, 5- and 10-year patient survivals were 90% and 81% for split recipients and 99% and 96% for whole recipients, respectively (P = 0.34). The 5- and 10-year graft survivals were also comparable: 87% and 77% for split recipients, and 86% and 82% for whole recipients (P = 0.86). Cox regression analysis identified donor age >50, donor-to-recipient weight ratio < 1, retransplantation status, and United Network for Organ Sharing I-IIA status as risk factors for partial graft use. There were no significant differences in 5-year outcomes based on center volume. In conclusion, we demonstrate that adult liver transplantation with ERGs can achieve longterm success comparable with that of whole grafts in appropriate patients but should be selectively used in patients with risk factors. Liver Transplantation 23 1384-1395 2017 AASLD.

Early complications after liver transplantation in children and adults: Are split grafts equal to each other and equal to whole livers?

Split-liver transplantation (LT) allows transplantation of two recipients from one deceased donor, thereby increasing pool of grafts. However, split LT may be hampered by technical problems, and split grafts are still considered suboptimal organs in some centres. We analysed the outcomes in split- and whole-liver recipients in a combined adult-to-paediatric transplantation programme. Records of paediatric and adult patients having undergone LT from 1999 to 2013 were analysed retrospectively. All splits were performed in situ. Adult split-graft recipients were matched 1:2 with whole-graft recipients (matching criteria: BMI, MELD, year of transplantation, age), and matched to the paediatric recipient transplanted from the same donor. Post-LT complications were classified according to the Clavien scale. Among children, 32 split- and 31 whole-graft recipients were analysed. Among adults, 20 split- and 40 matched whole-graft recipients were analysed. In both populations, the post-operative complications did not differ between split- and whole-graft recipients. There was no difference in 1-year graft and patient survival between split- and whole-graft recipients in paediatric (90% vs. 97%, 94% vs. 97%, respectively) and in adult recipients (89% in both, 89% vs. 92%, respectively). In the analysis of both recipients issued from the same donor, there was no association in the prevalence and severity of complications. A case-by-case analysis showed that split mortality was unrelated to LT in all but one patient (small-for-size left split graft). In the setting of careful donor selection, recipient matching and surgical skill, in situ split LT is an effective and safe technique to increase the number of available organs, and split livers should no longer considered marginal grafts.

Right lobe split liver transplantation versus whole liver transplantation in adult recipients: A systematic review and meta-analysis

Split liver transplantation (SLT) has proven to be an effective technique to reduce the mortality of children on the waiting list, but whether creating 2 split grafts from 1 standard-criteria whole liver would compromise outcomes of adult recipients remains uncertain. We conducted this meta-analysis to compare outcomes of right lobe SLT and whole liver transplantation (WLT) in adult patients. PubMed, Embase, and the Cochrane Library were searched for relevant articles published before December 2014. Outcomes assessed were patient survival (PS), graft survival (GS), and major surgical complications after transplantation. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to synthesize the results. Seventeen studies with a total of 48,457 patients met the full inclusion criteria. PS and GS rates were all found to be equivalent between SLT and WLT recipients. However, SLT was associated with higher rates of overall biliary complications (OR = 1.66; 95% CI = 1.29-2.15; P < 0.001), bile leaks (OR = 4.30; 95% CI = 2.97-6.23; P < 0.001), overall vascular complications (OR = 1.81; 95% CI = 1.29-2.53; P < 0.001), hepatic artery thromboses (OR = 1.71; 95% CI = 1.17-2.50; P = 0.005), and outflow tract obstructions (OR = 4.17; 95% CI = 1.75-9.94; P = 0.001). No significant difference was observed in incidences of biliary stricture, portal vein complications, postoperative bleeding requiring surgical treatments, primary nonfunction, and retransplantations. In subgroup analyses, biliary and vascular complications only increased after ex vivo SLT rather than in situ SLT, and SLT recipients had more retransplantations if they matched with WLT recipients in terms of urgent status. In conclusion, adult right lobe SLT was associated with increased biliary and vascular complications compared with WLT, but it did not show significant inferiority in PSs and GSs.

Deceased-donor split-liver transplantation in adult recipients: is the learning curve over?

BACKGROUND

Infants have the highest wait-list mortality of all liver transplantation candidates. Deceased-donor split-liver transplantation, a technique that provides both an adult and pediatric graft, might be the best way to decrease this disproportionate mortality. Yet concern for an increased risk to adult split recipients has discouraged its widespread adoption. We aimed to determine the current risk of graft failure in adult recipients after split-liver transplantation.

STUDY DESIGN

United Network for Organ Sharing data from 62,190 first-time adult recipients of deceased-donor liver transplants (1995-2010) were analyzed (889 split grafts). Bivariate risk factors (p < 0.2) were included in Cox proportional hazards models of the effect of transplant type on graft failure.

RESULTS

Split-liver recipients had an overall hazard ratio of graft failure of 1.26 (p < 0.001) compared with whole-liver recipients. The split-liver hazard ratio was 1.45 (p < 0.001) in the pre-Model for End-Stage Liver Disease era (1995-2002) and 1.10 (p = 0.28) in the Model for End-Stage Liver Disease era (2002-2010). Interaction analyses suggested an increased risk of split-graft failure in status 1 recipients and those given an exception for hepatocellular carcinoma. Excluding higher-risk recipients, split and whole grafts had similar outcomes (hazard ratio = 0.94; p = 0.59).

CONCLUSIONS

The risk of graft failure is now similar between split and whole-liver recipients in the vast majority of cases, which demonstrates that the expansion of split-liver allocation might be possible without increasing the overall risk of long-term graft failure in adult recipients. Additional prospective analysis should examine if selection bias might account for the possible increase in risk for recipients with hepatocellular carcinoma or designated status 1.

Deceased donor risk factors influencing liver transplant outcome

As the pressure for providing liver transplantation to more and more candidates increases, transplant programs have begun to consider deceased donor characteristics that were previously considered unacceptable. With this trend, attention has focused on better defining those donor factors that can impact the outcome of liver transplantation. This review examines deceased donor factors that have been associated with patient or graft survival as well as delayed graft function and other liver transplant results.

Split liver transplantation using extended right grafts: the natural history of segment 4 and its impact on early postoperative outcomes

Split liver transplantation (SLT) using extended right grafts is associated with complications related to ischemia of hepatic segment 4 (S4), and these complications are associated with poor outcomes. We retrospectively analyzed 36 SLT recipients so that we could assess the association of radiological, biological, and clinical features with S4 ischemia. The overall survival rates were 84.2%, 84.2%, and 77.7% at 1, 3, and 5 years, respectively. The recipients were mostly male (24/36 or 67%) and had a median age of 52 years (range = 13-63 years), a median body mass index of 22.9 kg/m(2) (range = 17.3-29.8 kg/m(2) ), and a median graft-to-recipient weight ratio of 1.3% (range = 0.9%-1.9%). S4-related complications were diagnosed in 22% of the patients (8/36) with a median delay of 22 days (range = 10-30 days). Secondary arterial complications were seen in 3 of these patients and led to significantly decreased graft survival in comparison with the graft survival of patients without complications (50.0% versus 85.6%, P = 0.017). Patients developing S4-related complications had significantly elevated aspartate aminotransferase (AST) levels (>1000 IU/L) on postoperative day (POD) 1 and elevated gamma-glutamyl transpeptidase (GGT) levels (>300 IU/L) on PODs 7 and 10 (P < 0.05). These AST and GGT elevations conferred a significantly high risk of developing these complications (odds ratio = 42, 95% confidence interval = 4-475, P < 0.05). The ischemic volume of S4 was extremely variable (0%-95%) and did not correlate with S4-related complications. In conclusion, our results suggest that S4-related complications are risk factors for worse graft survival, and the development of these complications can be anticipated by the early identification of a specific biological profile and a routine radiological examination.

Where are we today in split liver transplantation?

PURPOSE OF REVIEW

Results of surgical innovations using partial liver grafts from deceased donors have improved the availability of transplantable organs. However, current data on outcomes after split liver transplantation (SLT) are conflicting. This article reviews the current state of SLT, focusing on long-term outcomes and predictors for patient and graft survival after SLT.

RECENT FINDINGS

The conventional SLT has been proven to be a durable life-saving procedure. Early results for full left-right SLT for two adults are promising but this technique had not showed efficacy for wide application. Predictors of diminished patient survival after SLT included the use of split grafts in critically ill recipients (model for end-stage liver disease score >30), retransplant patients, cold ischemia time more than 10 h, and the performance of SLT in low-volume liver transplant centers.

SUMMARY

Conventional SLT performed in specialized centers resulted in long-term survival outcomes comparable with whole-organ liver transplantation. Full left-right SLT for two adults remains experimental. Splitting of the liver is an effective approach to expand the donor pool and remains an untapped resource for patients in need of liver transplantation. Split graft-to-recipient pairing is crucial for optimal organ allocation and survival outcomes after liver transplantation.