Factors affecting graft survival after adult/child split-liver transplantation: analysis of the UNOS/OPTN data base

Aborted living-donor liver transplantation in the real-world setting, lessons from 13 937 cases of Vanguard Multi-center Study of International Living Donor Liver Transplantation Group

There are exceedingly uncommon but clearly defined situations where intraoperative abortions are inevitable in living-donor liver transplantation (LDLT). This study aimed to summarize the cases of aborted LDLT and propose a strategy to prevent abortion or minimize donor damage from both recipient and donor sides. We collected data from a total of 43 cases of aborted LDLT out of 13 937 cases from 7 high-volume hospitals in the Vanguard Multi-center Study of the International Living Donor Liver Transplantation Group and reviewed it retrospectively. Of the 43 cases, there were 24 recipient-related abortion cases and 19 donor-related cases. Recipient-related abortions included pulmonary hypertension (n = 8), hemodynamic instability (n = 6), advanced hepatocellular carcinoma (n = 5), bowel necrosis (n = 4), and severe adhesion (n = 1). Donor-related abortions included graft steatosis (n = 7), graft fibrosis (n = 5), primary biliary cholangitis (n = 3), anaphylactic shock (n = 2), and hemodynamic instability (n = 2). Total incidence of aborted LDLT was 0.31%, and there was no remarkable difference between the centers. A strategy to minimize additional donor damage by delaying the donor's laparotomy or trying to open the recipient's abdomen with a small incision should be effective in preventing some causes of aborted LDLT, such as pulmonary hypertension, advanced cancer, and severe adhesions.

Impact of donor age on short-term outcomes after pediatric split liver transplantation

Background

Donor shortage is an important limitation of liver transplantation (LT). Split liver transplantation (SLT) may increase the sources of donors and reduce the problem of organ shortage. However, there are no standard criteria of the selection of SLT donor, especially regarding the donor age.

Methods

We retrospectively analyzed the clinical data of children who received initial SLT between January 2015 and December 2021. Based on the age of donors, the patients were divided into groups A (1-10 years old; n = 26), B (10-45 years old; n = 87), and C (45-55 years old; n = 27). The short-term (<1 year after SLT) outcomes of the recipients were analyzed.

Results

A total of 140 patients received SLT from 122 donors. The 1-, 3- and 12-month patient survival rates in group A were 100.0%, and the graft survival rates were 92.3%. The 1-, 3- and 12-month survival rates of patient and graft in group B were 97.7%, 96.6%, and 95.0%, respectively, and in group C were 85.2%, 85.2%, and 81.1%, respectively. The patient survival rate was significantly lower in group C than in groups A and B (p = 0.0082). There was no significant difference in graft survival between the three groups (p = 0.0545).

Conclusions

Similar results were obtained for pediatric SLT with donors <10 years old and 10-45 years old. Pediatric SLT can be performed with older donors (45-55 years) after strict donor selection and selection of appropriate recipients.

Impact of allograft types on outcomes after pediatric liver transplantation due to biliary atresia

BACKGROUND

Several surgical strategies, including split donor transplantation and living donor transplantation, have been used to increase the donor liver pool. This report focuses on the effects of whole, split, and LDLT on recipient outcomes.

METHODS

We retrospectively analyzed the records of all patients with biliary atresia at Tianjin First Central Hospital between April 2013 and December 2019.

RESULTS

A total of 882 patients were included and divided into three groups by graft type, with 198 in the whole-liver-transplantation group, 78 in the split liver transplantation group, and 606 in the LDLT group. The median follow-up time was 39 months, patient survival rates of three groups were 94.4%, 88.5%, and 95.0%, respectively, and graft survival rates were 90.2%, 83.3%, and 94.7%, respectively. We divided the split liver transplantation group into two subgroups according to the donor's age, and patient survival rates exhibited a significant difference only in the group whose donor age was over 45 years. The postoperative complication rates were significantly higher with respect to hepatic artery thrombosis, portal stenosis, and AR; and lower in hepatic venous stenosis, PTLDs, CMV virus, and EBV infection in the WLT group. Our multivariate model showed that donor age ≥45 years, RBC transfusion, pneumonia, and HAT were the independent predictors of allograft loss.

CONCLUSIONS

The survival of split liver transplantation group was slightly lower. The types of complications are different from different graft types. Therefore, postoperative monitoring and treatment need to be adjusted according to the different graft types used.

Liver transplantation of partial grafts after ex situ splitting during hypothermic oxygenated perfusion-The HOPE-Split pilot study

Partial liver grafts from ex situ splitting are considered marginal due to prolonged static cold storage. The use of ex situ hypothermic oxygenated perfusion (HOPE) may offer a strategy to improve preservation of ex situ split grafts. In this single-center pilot study, we prospectively performed ex situ liver splitting during HOPE (HOPE-Split) for adult and pediatric partial grafts over a 1-year period (November 1, 2020 to December 1, 2021). The primary safety endpoint was based on the number of liver graft-related adverse events (LGRAEs) per recipient, including primary nonfunction, biliary complications, hepatic vascular complications, and early relaparotomies and was compared with consecutive single-center standard ex situ split transplantations (Static-Split) performed from 2018 to 2020. Secondary endpoints included preservation characteristics and early outcomes. Sixteen consecutive HOPE-Split liver transplantations (8 HOPE-Split procedures) were included and compared with 24 Static-Splits. All HOPE-Split grafts were successfully transplanted, and no graft loss nor recipient death was encountered during the median follow-up of 7.5 months (interquartile range, 5.5-12.5). Mean LGRAE per recipient was similar in both groups (0.31 ± 0.60 vs. 0.46 ± 0.83; p = 0.78) and split duration was not significantly increased for HOPE-Split (216 vs. 180 min; p = 0.45). HOPE-Split grafts underwent perfusion for a median of 125 min, which significantly shortened static cold storage (472 vs. 544 min; p = 0.001), whereas it prolonged total ex vivo preservation (595 vs. 544 min; p = 0.007) and reduced neutrophil infiltration on reperfusion biopsies (p = 0.04) compared with Static-Split. This clinical pilot study presents first feasibility and safety data for transplantation of partial liver grafts undergoing ex situ split during HOPE and suggests improved preservation compared with static ex situ splitting. These preliminary results will allow to set up large-scale trials on the use of machine perfusion in pediatric and split-liver transplantation.

Development of a risk score model for 1-year graft loss after adult deceased donor liver transplantation in Japan based on a 20-year nationwide cohort

Aim

Using nationwide data collected over the past 20 years, we aimed to investigate deceased donor liver transplantation (DDLT) outcomes to develop a unique risk model that can be used to establish a standard for organ acceptance in Japan.

Methods

Data were collected for 449 recipients aged ≥18 years who underwent DDLT between 1999 and 2019. Least absolute shrinkage and selection operator (LASSO) regression analysis was utilized to develop an original risk score model for 1-year graft loss (termed the Japan Risk Index [JRI]). We developed risk indices according to recipient, donor, and surgery components (termed JRI-R, D, and S, respectively). The JRI was validated via a 5-fold cross-validation. We also compared DDLT outcomes and risk indices among Era1 (-2011), Era2 (-2015), and Era3 (-2019).

Results

The 1-year graft survival rate was 89.5% and improved significantly, reaching 84.7%, 87.6%, and 93.9% in Era1, Era2, and Era3, respectively. The JRI was calculated as JRI-R (re-transplantation, Model for End-Stage Liver Disease score, medical condition in intensive care unit) × JRI-D (age, catecholamine index, maximum sodium, maximum total bilirubin) × JRI-S (total ischemic time) × 0.84. The risk model achieved a mean C-statistic value of 0.81 in the validation analysis. The risk index was significantly lower in Era3 than in Era2.

Conclusion

Changes in the risk index over time indicated that avoiding risks contributed to the improved outcomes in Era3. The JRI is unique to adult DDLT in Japan and may be useful as a reference for organ acceptance in the future.

Normothermic Machine Perfusion in pediatric liver transplantation: A survey of attitudes and barriers

BACKGROUND

NMP provides a superior strategy for the assessment and preservation of marginal donor livers and has demonstrated increased utilization and enhances organ quality when used in adult liver transplantation. We aimed to evaluate the interest of incorporating the use of NMP in pediatric liver transplantation.

METHODS

An anonymous online survey was distributed to pediatric transplant surgeons and hepatologists across the United States. Respondent demographic information, attitudes toward NMP in pediatric liver transplantation, and barriers to utilization were examined.

RESULTS

Thirty-two providers (18 transplant surgeons and 14 hepatologists) completed the survey, yielding a response rate of 64%. Half (50%) of respondents indicated prior exposure to NMP. Overall, 96% of respondents believed there was benefit to using NMP in pediatric liver transplantation. DCD (68%) and post-cross-clamp (75%) grafts were the greatest opportunity for NMP use. A role in splitting livers ex vivo (71%) was also seen as a potential major opportunity. Cost was perceived as a barrier to implementation (36%), followed by institutional factors (32%). Cost tolerance was significantly greater in respondents residing in OPTN regions with greater than median wait times (63% vs. 11% in OPTN regions with greater vs. shorter wait times, p = .010).

CONCLUSIONS

There is significant interest within the pediatric liver transplant community for NMP to expand the donor pool. Interest appears particularly strong in regions where wait times for suitable pediatric donors are prolonged.

Graft weight integration in the early allograft dysfunction formula improves the prediction of early graft loss after liver transplantation

The role of the graft-to-recipient weight ratio (GRWR) in adult liver transplantation (LT) has been poorly investigated so far. The aim is to evaluate the contribution of the GRWR to the well-recognized early allograft dysfunction (EAD) model (i.e., Olthoff model) for the prediction of 90-day graft loss after LT in adults. Three hundred thirty-one consecutive adult patients undergoing LT between 2009 and 2018 at Tor Vergata and Sapienza University in Rome, Italy, served as the Training-Set. The Validation-Set included 123 LTs performed at the Erasmus Medical Center, Rotterdam, the Netherlands. The mEAD model for 90-day graft loss included the following variables: GRWR \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\le $$\end{document}≤ 1.57 = 2.5, GRWR \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\ge $$\end{document}≥ 2.13 = 2.5, total bilirubin ≥ 10.0 mg/dL = 2.0, INR ≥ 1.60 = 2.3, and aminotransferase > 2000 IU/L = 2.2. The mEAD model showed an AUC = 0.74 (95%CI = 0.66–0.82; p < 0.001) and AUC = 0.68 (95%CI = 0.58–0.88; p = 0.01) in the Training-Set and Validation-Set, respectively, outperforming conventional EAD in both cohorts (Training-Set: AUC = 0.64, 95%CI = 0.57–0.72; p = 0.001; Validation-Set: AUC = 0.52, 95%CI = 0.35–0.69, p = 0.87). Incorporation of graft weight in a composite multivariate model allowed for better prediction of patients who presented an aminotransferase peak > 2000 IU/L after LT (OR = 2.39, 95%CI = 1.47–3.93, p = 0.0005). The GRWR is important in determining early graft loss after adult LT, and the mEAD model is a useful predictive tool in this perspective, which may assist in improving the graft allocation process.

Recipient-Specific Risk Factors Impairing Patient and Graft Outcome after Pediatric Liver Transplantation-Analysis of 858 Transplantations in 38 Years

(1) Background and Aim: Despite excellent long-term results in pediatric liver transplantation (pLTx), mortality and graft loss still are to be diminished. We aim to describe time-dependent changes and long-term outcome of a large single-center pLTx cohort and to identify independent recipient-related risk factors impairing patient and graft survival. (2) Methods: This is a retrospective single-center study analyzing all pediatric liver transplants from 1983–2020. Risk factors for mortality and graft loss were identified by univariable and multi-linear regression analysis. (3) Results: We analyzed 858 liver transplantations in 705 pediatric patients. Five-year patient/graft survival increased from 60.9%/48.0% (1983–1992) to 97.5%/86.5% (OR = 12.5; p < 0.0001/OR = 6.5; p < 0.0001) (2014–2020). Indications changed significantly over time, with a higher proportion of patients being transplanted for malignancies and metabolic disease and indications of PFIC and α1AT-deficiency declining. The era of transplantation (log7.378/9.657; p < 0.0001) and indication of acute liver failure (log = 1.944/2.667; HR = 2.015/1.772; p = 0.0114/0.002) impairs patient/graft survival significantly in the multivariate analysis. Furthermore, patient survival is worsened by re-transplantation (log = 1.755; HR = 1.744; p = 0.0176) and prolonged waiting times in high-urgency status (log = 2.588; HR = 1.073; p = 0.0026), whereas the indication of biliary atresia improved outcome (log = 1.502; HR = 0.575; p = 0.0315). Graft survival was additionally impaired by pre-existing portal vein thrombosis (log = 1.482; HR = 2.016; p = 0.0330). (4) Conclusions: Despite more complex indications, patient and graft survival after pLTx continue to improve.. Acute liver failure remains the indication with poorest outcome, and listing for high urgency liver transplantation should be considered carefully and early to keep waiting time on HU list short. Furthermore, pre-transplant portal vein thrombosis should be prevented whenever possible to improve graft survival.

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.

Logistic Coordination in Pediatric Liver Transplantation: Criteria for Optimization

INTRODUCTION

Logistic organization of the transplantation coordination process aims to synchronize the recovery and recipient team and to reduce to a minimum the graft's cold ischemia time (CIT), which, in turn, is known, to have deleterious effects on the graft and recipient, if prolonged. To determine whether variables influencing the different steps in the coordination process might allow for reducing CIT, this study aimed to analyze these variables.

PATIENTS AND METHODS

Retrospective analysis of 61 pediatric liver transplantations from 2006 to 2015 in the Geneva University Hospitals.

RESULTS

Length of donor hepatectomy was increased for split grafts (P < .0001). Length of recipient hepatectomy was longer in the case of previous surgery (P = .06). The recipient team waiting time for the graft was longer for split grafts (P = .01). The graft waiting time at the recipient site was longer for whole grafts (P = .0005) and increased recipient weight (P = .03). The graft waiting time at the donor site was doubled in the case of recovery of organs after the liver by the same team (P = .007). The graft waiting time at the donor and recipient site not surprisingly increased the CIT (P = .007 and < .0001, respectively).

CONCLUSION

CIT depends on waiting times during the entire coordination process, which largely depends on the estimation of hepatectomy lengths. A more accurate estimation, considering graft type and recipient's previous surgery and weight, might allow for decreasing CIT and consequently improve outcomes after pediatric liver transplantation.

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.

A national mandatory-split liver policy: A report from the Italian experience

To implement split liver transplantation (SLT) a mandatory-split policy has been adopted in Italy since August 2015: donors aged 18-50 years at standard risk are offered for SLT, resulting in a left-lateral segment (LLS) graft for children and an extended-right graft (ERG) for adults. We aim to analyze the impact of the new mandatory-split policy on liver transplantation (LT)-waiting list and SLT outcomes, compared to old allocation policy. Between August 2015 and December 2016 out of 413 potentially "splittable" donors, 252 (61%) were proposed for SLT, of whom 53 (21%) donors were accepted for SLT whereas 101 (40.1%) were excluded because of donor characteristics and 98 (38.9%) for absence of suitable pediatric recipients. The SLT rate augmented from 6% to 8.4%. Children undergoing SLT increased from 49.3% to 65.8% (P = .009) and the pediatric LT-waiting list time dropped (229 [10-2121] vs 80 [12-2503] days [P = .045]). The pediatric (4.5% vs 2.5% [P = .398]) and adult (9.7% to 5.2% [P < .001]) LT-waiting list mortality reduced; SLT outcomes remained stable. Retransplantation (HR = 2.641, P = .035) and recipient weight >20 kg (HR = 5.113, P = .048) in LLS, and ischemic time >8 hours (HR = 2.475, P = .048) in ERG were identified as predictors of graft failure. A national mandatory-split policy maximizes the SLT donor resources, whose selection criteria can be safely expanded, providing favorable impact on the pediatric LT-waiting list and priority for adult sick LT candidates.

Elevated Risk of Split-Liver grafts in adult liver Transplantation: Statistical Artifact or Nature of the Beast?

A recent study using US national registry data reported, using Cox proportional hazards (PH) models, that split-liver transplantation (SLT) has improved over time and is no more hazardous than whole-liver transplantation (WLT). However, the study methods violated the PH assumption, which is the fundamental assumption of Cox modeling. As a result, the reported hazard ratios (HRs) are biased and unreliable. This study aimed to investigate whether the risk of graft survival (GS) in SLT has really improved over time, ensuring attention to the PH assumption. This study included 80,998 adult deceased donor liver transplantation (LT) (1998-2015) from the Scientific Registry Transplant Recipient. The study period was divided into 3 time periods: era 1 (January 1998 to February 2002), era 2 (March 2002 to December 2008), and era 3 (January 2009 to December 2015). The PH assumption was tested using Schoenfeld's test, and where the HR of SLT violated the assumption, changes in risk for SLT over time from transplant were assessed. SLT was performed in 1098 (1.4%) patients, whereas WLT was used in 79,900 patients. In the Cox PH analysis, the P values of Schoenfeld's global tests were <0.05 in all eras, which is consistent with deviation from proportionality. Assessing HRs of SLT with a time-varying effect, multiple Cox models were conducted for post-LT intervals. The HR curves plotted according to time from transplant were higher in the early period and then decreased at approximately 1 year and continued to decrease in all eras. For 1-year GS, the HRs of SLT were 1.92 in era 1, 1.52 in era 2, and 1.47 in era 3 (all P < 0.05). In conclusion, the risk of SLT has a time-varying effect and is highest in the early post-LT period. The risk of SLT is underestimated if it is evaluated by overall GS. SLT was still hazardous if the PH assumption was considered, although it became safer over time.

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.

Survival Outcomes in Split Compared With Whole Liver Transplantation

Split-liver transplantation (SLT) should be cautiously considered because the right trisection (RTS) graft can be a marginal graft in adult recipients. Herein, we analyzed the outcomes of RTS-SLT in Korea, where >75% of adult liver transplantations are performed with living donor liver transplantation. Among 2462 patients who underwent deceased donor liver transplantations (DDLTs) from 2005 to 2014, we retrospectively reviewed 86 (3.5%) adult patients who received a RTS graft (RTS-SLT group). The outcomes of the RTS-SLT group were compared with those of 303 recipients of whole liver (WL; WL-DDLT group). Recipient age, laboratory Model for End-Stage-Liver Disease (L-MELD) score, ischemia time, and donor-to-recipient weight ratio (DRWR) were not different between the 2 groups (P > 0.05). However, malignancy was uncommon (4.7% versus 36.3%), and the donor was younger (25.2 versus 42.7 years) in the RST-SLT group than in the WL-DDLT group (P < 0.05). The technical complication rates and the 5-year graft survival rates (89.0% versus 92.8%) were not different between the 2 groups (P > 0.05). The 5-year overall survival (OS) rate (63.1%) and graft-failure-free survival rate (63.1%) of the RTS-SLT group were worse than that of the WL-DDLT group (79.3% and 79.3%; P < 0.05). The factors affecting graft survival rates were not definite. However, the factors affecting OS in the RTS-SLT group were L-MELD score >30 and DRWR ≤1.0. In the subgroup analysis, OS was not different between the 2 groups if the DRWR was >1.0, regardless of the L-MELD score (P > 0.05). In conclusion, a sufficient volume of the graft estimated from DRWR-matching could lead to better outcomes of adult SLTs with a RTS graft, even in patients with high L-MELD scores.

The rate of hepatic artery complications is higher in pediatric liver transplant recipients with metabolic liver diseases than with biliary atresia

BACKGROUND

Liver transplantation (LT) is an excellent treatment option for patients with biliary atresia (BA) who fail portoenterostomy surgery. LT is also increasingly performed in patients with metabolic liver diseases. This study compared the outcomes in pediatric patients who underwent LT for metabolic liver diseases and BA.

BASIC PROCEDURES

Data from 237 pediatric patients who underwent primary LT at Seoul National University Hospital from 1988 to 2015, including 33 with metabolic liver diseases and 135 with BA, were retrospectively analyzed.

MAIN FINDINGS

Compared with children with BA, children with metabolic liver diseases were significantly older at the time of LT (121.3 vs. 37.3 months; P < 0.001), and had lower Child-Pugh (7.1 vs. 8.4; P = 0.010) and Pediatric End-stage Liver Disease (6.5 vs. 12.8; P = 0.042) scores. Overall survival rates were similar (87.8% vs. 90.8%; P = 0.402), but hepatic artery (HA) complications were significantly more frequent in children with metabolic liver diseases (12.1% vs. 1.5%; P = 0.014).

PRINCIPAL CONCLUSION

Despite similar overall survival, children with metabolic liver diseases had a higher rate of HA complications.

TYPE OF SUBMISSION

Original article, Case control study, Retrospective.

EVIDENCE LEVEL

III.

Outcomes of left split graft transplantation in Europe: report from the European Liver Transplant Registry

Split liver transplantation (SLT) has been widely adopted across Europe, resulting in remarkable reduction in the paediatric waiting-list mortality. Left split graft (LSG) is commonly used for paediatric recipients; however, deceased donor criteria selection are not universal. The aim of this study was to analyse the LSG outcome from the European Liver Transplant Registry and to identify risk factors for graft failure. Data from 1500 children transplanted in 2006-2014 with LSG from deceased donors were retrospectively analysed. Overall, graft losses were 343(22.9%) after 5 years from transplantation, 240(70.0%) occurred within the first 3 months. Estimated patient survival was 89.1% at 3 months and 82.9% at 5 years from SLT. Re-transplantation rate was 11.5%. At multivariable analysis, significant risk factors for graft failure at 3 months included the following: urgent SLT (HR = 1.73, P = 0.0012), recipient body weight ≤6 kg (HR = 1.91, P = 0.0029), donor age >50 years (HR = 1.87, P = 0.0039), and cold ischaemic time (CIT) [HR = 1.07 per hour, P = 0.0227]. LSG has good outcomes and SLT is excellent option for paediatric recipients in the current organ shortage era. We identified practical guidelines for LSG donor and recipient selection criteria: donor age may be safely extended up to 50 years in the absence of additional risk factors; thus, children <6 kg and urgent transplantation need CIT <6 h and appropriate graft/recipient size-matching to achieve good outcomes.

Donation after Circulatory Death in Paediatric Liver Transplantation: Current Status and Future Perspectives in the Machine Perfusion Era

Efforts have been made by the transplant community to expand the deceased donor pool in paediatric liver transplantation (LT). The growing experience on donation after circulatory death (DCD) for adult LT has encouraged its use also in children, albeit in selective cases, opening new perspectives for paediatric patients. Even though there has recently been a slight increase in the number of DCD livers transplanted in children, with satisfactory graft and patient outcomes, the use of DCD grafts in paediatric recipients is still controversial due to morbid outcomes associated with DCD grafts. In this context, recent advances in the optimization of donor support by extracorporeal membrane oxygenation and in the graft preservation by liver machine perfusion could find application in order to expand the donor pool in paediatric LT. In the present study we review the current literature on DCD liver grafts transplanted in children and on the use of extracorporeal donor support and liver perfusion machines in paediatrics, with the aim of defining the current status and future perspectives of paediatric LT.

Higher retransplantation rate following extended right split-liver transplantation: An analysis from the eurotransplant liver follow-up registry

Split-liver transplantation has been perceived as an important strategy to increase the supply of liver grafts by creating 2 transplants from 1 allograft. The Eurotransplant Liver Allocation System (ELAS) envisages that the extended right lobes (ERLs) after splitting (usually in the pediatric center) are almost exclusively shipped to a second center. Whether the ELAS policy impacts the graft and patient survival of extended right lobe transplantation (ERLT) in comparison to whole liver transplantation (WLT) recipients remains unclear. Data on all liver transplantations performed between 2007 and 2013 were retrieved from the Eurotransplant Liver Follow-up Registry (n = 5351). Of these, 5013 (269 ERL, 4744 whole liver) could be included. The impact of the transplant type on patient and graft survival was evaluated using univariate and multivariate proportional hazard models adjusting for demographics of donors and recipients. Cold ischemia times were significantly prolonged for ERLTs (P < 0.001). Patient survival was not different between ERLT and WLT. In the univariate analysis, ERLT had a significantly higher risk for retransplantation (P = 0.02). For WLT, the risk for death gradually and significantly increased with laboratory Model for End-Stage Liver Disease (MELD) scores of >20. For ERLT, this effect was seen already with laboratory MELD scores of >14. These results mandate a discussion on how to refine the splitting policy to avoid excess retransplant rates in ERL recipients and to further improve transplant outcomes of these otherwise optimal donor organs. Liver Transplantation 24 26-34 2018 AASLD.

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.

The impact of intercenter sharing on the outcomes of pediatric split liver transplantation

BACKGROUND

Split liver transplantation allows for expansion of the pool of organs available for pediatric liver transplantation. The impact of sharing segments of the same liver between centers has not been studied.

STUDY DESIGN

Retrospective analysis of 24 pediatric split liver transplant cases in a recent cohort. We evaluated the outcomes of pediatric recipients who shared organs with adult patients in our own center (group A) compared to recipients who shared organs with adult patients in other centers. (group B).

RESULTS

One-, 3-, and 5-year graft survival for group A was 100%, 100%, and 100% vs 83%, 71%, and 57% for group B (P = .039). Postoperative complications included biliary complications (41.7% in group A vs 50% in group B, P = .682), vascular complications (8.3% in group A vs 41.7% in group B, P = .059), and postoperative bleeding (16.7% in group A vs 25% in group B, P = .615). High-grade Clavien-Dindo complications were 0% in group A vs 33.3% in group B, P = .028.

CONCLUSIONS

Organ sharing between centers appears to be associated with significantly poorer graft survival. Possible explanations include greater procurement-related injury or suboptimal vessel distribution. Future larger studies focused on this area may be helpful to formulate policy considerations.

In Situ Splitting of the Cadaver Liver for Two Adult Recipients by LDLT Technique

BACKGROUND

To expand the donor pool, split liver transplantation is conventionally performed for one adult and one pediatric recipient. Application of this technique for two adult recipients can produce remarkable impact on the waiting list. Proper donor and recipient selection is crucial for the favorable outcome following full-right and full-left liver split. Right lobe adult to adult living donor liver transplantation (LDLT) is essentially a full right and full left split. However, LDLT techniques have not been used for full right and left split.

METHODS

We performed in situ splitting of the whole liver using LDLT techniques from a hemodynamically stable young deceased donor and transplanted into two adult recipients, both with model for end-stage liver disease score of 17. The transection was carried out through the midplane of liver, generating a right lobe and a left lobe graft.

RESULTS

Both the recipients had uneventful postoperative recovery. At ten months of follow up, both the recipients are doing well with good liver function.

CONCLUSION

Based on the concept of living related liver transplantation, our case explores the technical feasibility of full-right and full-left in situ liver split.

Elevated HbA1c in donor organs from patients without a diagnosis of diabetes portends worse liver allograft survival

Recipients of liver allografts from diabetic donors have decreased graft survival. However, limited data exist on the effects of donor HbA1c. We hypothesized that allografts from nondiabetic donors with elevated HbA1c would be associated with decreased survival. Liver transplant recipients from the UNOS database from nondiabetic donors were stratified into two groups: euglycemic (HbA1c<6.5) and hyperglycemic (HbA1c≥6.5). Propensity score matching (10:1) was used to adjust for donor and recipient characteristics. Kaplan-Meier analysis was used to assess survival. Donors of hyperglycemic allografts were older (49 vs 36, P<.001), were more likely to be non-white, had a higher BMI (29.8 vs 26.2, P<.001), were more likely to engage in heavy cigarette use (1.5% vs 1.3%, P=.004), had higher serum creatinine levels (1.3 vs 1.0, P=.002), and were more likely to be an expanded-criteria donor (35.8% vs 14.4%, P<.001). After propensity matching to account for these differences, allograft survival was significantly decreased in the recipients of hyperglycemic allografts (P=.049), and patient survival showed a trend toward reduction (P=.082). These findings suggest that HbA1c may be a simple and inexpensive test with potential utility for better organ risk stratification.

Korean Patients Undergoing Deceased Donor Liver Transplantation for Alcoholic Liver Disease Have Non-Inferior Survival Outcomes than for Hepatitis B Virus: a Real-World Experience without Minimum Abstinence before Transplantation

Few studies have compared outcomes in patients undergoing liver transplantation (LT) for hepatitis B virus (HBV) and alcoholic liver disease (ALD) in Asian countries in which living donor LT (LDLT) is dominant, where HBV is endemic and where there are no strict regulations on pre-transplant abstinence for ALD. This study compared post-LT outcomes of deceased donor LT (DDLT) in patients with ALD and HBV. Data from 220 patients who underwent primary DDLT at Seoul National University Hospital from January 2010 to December 2014, including 107 with HBV and 38 with ALD, were retrospectively analyzed. Seventy-four patients (69.2%) in the HBV group and 30 (78.9%) in the ALD group had United Network for Organ Sharing (UNOS) status 2A (P = 0.250). There were no significant differences in their 1-year (90.7% vs. 92.1%) and 3-year (82.1% vs. 82.3%) overall survival rates (P = 1.000). Multivariate analysis showed that high serum gamma glutamyltransferase concentration (≥ 70 IU/L) was independently prognostic of 1-year post-LT overall survival. Survival outcomes following DDLT were similar in Korean patients with ALD and HBV, even in the absence of strict pre-transplant abstinence from alcohol as a selection criterion.

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.

Current challenges and future directions for liver transplantation

Liver transplantation is an effective and widely used therapy for several patients with acute and chronic liver diseases. The discrepancy between the number of patients on the waiting list and available donors remains the key issue and is responsible for the high rate of waiting list mortality. The recent news is that the majority of patients with hepatitis C virus related liver disease will be cured by new antivirals therefore we should expect soon a reduction in the need of liver transplantation for these recipients. This review aims to highlight, in two different sections, the main open issues of liver transplantation concerning the current and future strategies to the best use of limited number of organs. The first section cover the strategies to increase the donor pool, discussing the use of older donors, split grafts, living donation and donation after cardiac death and mechanical perfusion systems to improve the preservation of organs before liver transplantation. Challenges in immunosuppressive therapy and operational tolerance induction will be evaluated as potential tools to increase the survival in liver transplant recipients and to reducing the need of re-transplantation. The second section is devoted to the evaluation of possible new indications to liver transplantation, where the availability of organs by implementing the strategies mentioned in the first section and the reduction in the number of waiting transplants for HCV disease is realized. Among these new potential indications for transplantation, the expansion of the Milan criteria for hepatocellular cancer is certainly the most open to question.

Split liver transplantation: Report of right and left graft outcomes from a multicenter Argentinean group

Grafts from split livers (SLs) constitute an accepted approach to expand the donor pool. Over the last 5 years, most Argentinean centers have shown significant interest in increasing the use of this technique. The purpose of this article is to describe and analyze the outcomes of right-side grafts (RSGs) and left-side grafts (LSGs) from a multicenter study. The multicenter retrospective study included data from 111 recipients of SL grafts from between January 1, 2009 and December 31, 2013. Incidence of surgical complications, patient and graft survival, and factors that affected RSG and LSG survival were analyzed. Grafts types were 57 LSG and 54 RSG. Median follow-up times for LSG and RSG were 46 and 42 months, respectively. The 36-month patient and graft survivals for LSG were 83% and 79%, respectively, and for RSG were 78% and 69%, respectively. Retransplantation rates for LSG and RSG were 3.5% and 11%, respectively. Arterial complications were the most common cause of early retransplantation (less than 12 months). Cold ischemia time (CIT) longer than 10 hours and the use of high-risk donors (age ≥ 40 years or body mass index ≥ 30 kg/m2 or ≥ 5 days intensive care unit stay) were independent factors for diminished graft survival in RSG. None of the analyzed variables were associated with worse graft survival in LSG. Biliary complications were the most frequent complications in both groups (57% in LSG and 33% in RSG). Partial grafts obtained from liver splitting are an excellent option for patients in need of liver transplantation and have the potential to alleviate the organ shortage. Adequate donor selection and reducing CIT are crucial for optimizing results.

Improving Research Practice in Rat Orthotopic and Partial Orthotopic Liver Transplantation: A Review, Recommendation, and Publication Guide

Background: Due to a worldwide shortage of donor organs for liver transplantation, alternative approaches, such as split and living donor liver transplantations, were introduced to increase the donor pool and reduce mortality on liver transplant waiting lists. Numerous details concerning the mechanisms and pathophysiology of liver regeneration, small-for-size syndrome, rejection, and tolerance in partial liver transplantation facilitated the development of various animal models. The high number of preclinical animal studies contributed enormously to our understanding of many clinical aspects of living donor and partial liver transplantations. Summary: Microsurgical rat models of partial orthotopic liver transplantation are well established and widely used. Nevertheless, several issues regarding this procedure are controversial, not clarified, or not yet properly standardized (graft rearterialization, size reduction techniques, etc.). The major aim of this literature review is to give the reader a current overview of rat orthotopic liver transplantation models with a special focus on partial liver transplantation. The aspects of model evolution, microsurgical training, and different technical problems are analyzed and discussed in detail. Our further aim in this paper is to elaborate a detailed publication guide in order to improve the quality of reporting in the field of rat liver transplantation according to the ARRIVE guidelines and the 3R principle. Key Messages: Partial orthotopic liver transplantation in rats is an indispensable, reliable, and cost-efficient model for transplantation research. A certain consensus on different technical issues and a significant improvement in scientific reporting are essential to improve transparency and comparability in this field as well as to foster refinement.

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.

The role of adult living donor liver transplantation and recent advances

Twenty years since the first cases were described, adult living donor liver transplantation (ALDLT) is now considered a valid option to expand the donor pool in view of the ongoing shortage of organs and the high waiting list mortality rate. Despite the rapid evolution and acceptance of this complex process of donation and transplantation in clinical practice, the indications, outcome, ethical considerations and quality and safety aspects continue to evolve based on new data from large cohort studies. This article reviews the surgical and clinical advances in the field of liver transplantation, focusing on technical refinements and discussing the issues that may lead to a further expansion of this complex surgical procedure and the role of ALDLT.

Challenges to liver transplantation and strategies to improve outcomes

Liver transplantation (LT) is a highly successful treatment for many patients with nonmalignant and malignant liver diseases. However, there is a worldwide shortage of available organs; many patients deteriorate or die while on waiting lists. We review the important clinical challenges to LT and the best use of the scarce organs. We focus on changes in indications for LT and discuss scoring systems to best match donors with recipients and optimize outcomes, particularly for the sickest patients. We also cover controversial guidelines for the use of LT in patients with hepatocellular carcinoma and cholangiocarcinoma. Strategies to increase the number of functional donor organs involve techniques to perfuse the organs before implantation. Partial LT (living donor and split liver transplantation) techniques might help to overcome organ shortages, and we discuss small-for-size syndrome. Many new developments could increase the success of this procedure, which is already one of the major achievements in medicine during the second part of the 20th century.

Scoring systems predict the prognosis of acute-on-chronic hepatitis B liver failure: an evidence-based review

Acute-on-chronic hepatitis B liver failure is a devastating condition that is associated with mortality rates of over 50% and is consequent to acute exacerbation of chronic hepatitis B in patients with previously diagnosed or undiagnosed chronic liver disease. Liver transplantation is the definitive treatment to lower mortality rate, but there is a great imbalance between donation and potential recipients. An early and accurate prognostic system based on the integration of laboratory indicators, clinical events and some mathematic logistic equations is needed to optimize treatment for patients. As parts of the scoring systems, the MELD was the most common and the donor-MELD was the most innovative for patients on the waiting list for liver transplantation. This review aims to highlight the various features and prognostic capabilities of these scoring systems.

The evolving use of higher risk grafts is associated with an increased incidence of acute kidney injury after liver transplantation

BACKGROUND & AIMS

The growing discrepancy between supply and demand for liver transplantation has necessitated a greater use of higher risk grafts. Donation after Circulatory Death (DCD) liver transplant recipients have an increased frequency of acute kidney injury (AKI). We hypothesised that other higher risk grafts might also impact negatively on renal function. Our aim was to examine the effect of the evolving use of higher risk grafts on the incidence of post liver transplant AKI.

METHODS

Single-centre study of 1152 patients undergoing first-single-organ liver transplantation for chronic liver disease 01/2000-12/2011. To assess the impact of the evolution of graft quality over time; donor/graft/recipient variables were compared over three 4-year periods.

RESULTS

Pretransplant recipient renal function improved during follow-up (p<0.001), and the median postoperative day-1 (p<0.001), -2 (p<0.001), and -3 (p<0.001) tacrolimus trough levels fell. The proportion of patients receiving a higher risk graft was 31.8% in 2000-2003, 40.9% in 2004-2007, and 59.1% in 2008-2011 (p<0.001). There was a progressive increase in AKI (2000-2003, OR 1.00; 2004-2007, OR 1.43; 2008-2011, OR 2.40, p<0.001). After adjusting for recipient variables increasing recipient warm ischaemic time (p=0.019), DCD transplantation (p<0.001), donor age ≥60 years (p=0.020), and donor body mass index ≥30 kg/m(2) (p<0.001) were independent predictors of AKI.

CONCLUSIONS

The increasing use of higher risk liver grafts is associated with an increased incidence of AKI. These findings support the need for therapies that minimise the hepatic ischaemia-reperfusion injury.

Aetiology and risk factors of ischaemic cholangiopathy after liver transplantation

Liver transplantation (LT) is the best treatment for end-stage hepatic failure, with an excellent survival rates over the last decade. Biliary complications after LT pose a major challenge especially with the increasing number of procured organs after circulatory death. Ischaemic cholangiopathy (IC) is a set of disorders characterized by multiple diffuse strictures affecting the graft biliary system in the absence of hepatic artery thrombosis or stenosis. It commonly presents with cholestasis and cholangitis resulting in higher readmission rates, longer length of stay, repeated therapeutic interventions, and eventually re-transplantation with consequent effects on the patient’s quality of life and increased health care costs. The pathogenesis of IC is unclear and exhibits a higher prevalence with prolonged ischaemia time, donation after circulatory death (DCD), rejection, and cytomegalovirus infection. The majority of IC occurs within 12 mo after LT. Prolonged warm ischaemic times predispose to a profound injury with a subsequently higher prevalence of IC. Biliary complications and IC rates are between 16% and 29% in DCD grafts compared to between 3% and 17% in donation after brain death (DBD) grafts. The majority of ischaemic biliary lesions occur within 30 d in DCD compared to 90 d in DBD grafts following transplantation. However, there are many other risk factors for IC that should be considered. The benefits of DCD in expanding the donor pool are hindered by the higher incidence of IC with increased rates of re-transplantation. Careful donor selection and procurement might help to optimize the utilization of DCD grafts.

The Physiology of Brain Death and Organ Donor Management

Brain death is associated with complex physiologic changes that may impact the management of the potential organ donor. Medical management is critical to actualizing the individual or family’s intent to donate and maximizing the benefit of that intent. This interval of care in the PICU begins with brain death and consent to donation and culminates with surgical organ procurement. During this phase, risks for hemodynamic instability and compromise of end organ function are high. The brain dead organ donor is in a distinct and challenging pathophysiologic condition that culminates in multifactorial shock. The potential benefits of aggressive medical management of the organ donor may include increased number of donors providing transplantable organs and increased number of organs transplanted per donor. This may improve graft function, graft survival, and patient survival in those transplanted. In this chapter, pathophysiologic changes occurring after brain death are reviewed. General and organ specific donor management strategies and logistic considerations are discussed. There is a significant opportunity for enhancing donor multi-organ function and improving organ utilization with appropriate PICU management.

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 liver transplantation in infants and small children: are partial grafts riskier than whole organs?

Infants have the highest wait-list mortality of all liver transplant candidates. Although previous studies have demonstrated that young children may be at increased risk when they receive partial grafts from adult and adolescent deceased donors (DDs), with few size-matched organs available, these grafts have increasingly been used to expand the pediatric donor pool. We aimed to determine the current adjusted risks of graft failure and mortality in young pediatric recipients of partial DD livers and to determine whether these risks have changed over time. We analyzed 2683 first-time recipients of DD livers alone under the age of 24 months in the United Network for Organ Sharing database (1995-2010), which included 1118 partial DD livers and 1565 whole DD organs. Transplant factors associated with graft loss in bivariate analyses (P < 0.1) were included in multivariate proportional hazards models of graft and patient survival. Interaction analysis was used to examine risks over time (1995-2000, 2001-2005, and 2006-2010). Although there were significant differences in crude graft survival by the graft type in 1995-2000 (P < 0.001), graft survival rates with partial and whole grafts were comparable in 2001-2005 (P = 0.43) and 2006-2010 (P = 0.36). Furthermore, although the adjusted hazards for partial graft failure and mortality were 1.40 [95% confidence interval (CI) = 1.05-1.89] and 1.41 (95% CI = 0.95-2.09), respectively, in 1995-2000, the adjusted risks of graft failure and mortality were comparable for partial and whole organs in 2006-2010 [hazard ratio (HR) for graft failure = 0.81, 95% CI = 0.56-1.18; HR for mortality = 1.02, 95% CI = 0.66-1.71]. In conclusion, partial DD liver transplantation has become less risky over time and now has outcomes comparable to those of whole liver transplantation for infants and young children. This study supports the use of partial DD liver grafts in young children in an attempt to significantly increase the pediatric organ pool.

Decreased Mrp2 transport in severe macrovesicular fatty liver grafts

BACKGROUND

Severe macrosteatotic liver has been regarded as a donor contraindication for liver transplantation. However, it has not yet been determined whether hepatocytes lose function before cold ischemia. This study was designed to elucidate certain pathophysiological alterations and how to ameliorate such hepatic dysfunctions.

MATERIALS AND METHODS

Wistar rats were fed with a choline-deficient diet (CD) for up to 6 wk, and their livers were then perfused with Krebs-Henseleit buffer to examine bile output and biliary constituents. Organic anion transport from hepatocellular canalicular membranes through Mrp2 was examined by kinetic analyses for biliary exclusion of 5-carboxyfluorescein (CF), a fluoroprobe excreted through Mrp2.

RESULTS

Macrovesicular fatty deposits exceeded 60% and serum aspartate aminotransferase (AST) increased on 6-wk CD (CD6w), but not 3-wk CD (CD3w). Mrp2-deficient rat livers (Eisai hyperbilirubinemia) with 3-wk CD were more vulnerable than CD3w livers. In CD6w rats, bile flow rate and biliary glutathione significantly decreased. These declines coincided with the intracellular localization of Mrp2. Moreover, kinetic analyses for biliary CF revealed significant delay in 6-wk CD-fed rat livers. Pioglitazone, a ligand of PPARγ activating protein kinase A (PKA), significantly attenuated this delay by sorting Mrp2 into bile canalicular membranes. However, a PKA inhibitor blunted the increase in CF exclusion, re-localizing Mrp2 into the hepatocellular cytoplasm. A thromboxane A2 synthase inhibitor also ameliorated the CF exclusion delay.

CONCLUSION

Pioglitazone activated PKA, increasing Mrp2 transports to detoxify xenobiotics. Pioglitazone may allow the donor indications for liver transplantation to be expanded to include severe macrovesicular fatty livers.

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.

Validation of the donor risk index in orthotopic liver transplantation within the Eurotransplant region

In Eurotransplant, more than 50% of liver allografts come from extended criteria donors (ECDs). However, not every ECD is the same. The limits of their use are being explored. A continuous scoring system for analyzing donor risk has been developed within the Organ Procurement and Transplantation Network (OPTN), the Donor Risk Index (DRI). The objective of this study was the validation of this donor risk index (DRI) in Eurotransplant. The study was a database analysis of all 5939 liver transplants involving deceased donors and adult recipients from January 1, 2003 to December 31, 2007 in Eurotransplant. Data were analyzed with Kaplan-Meier and Cox regression models. Follow-up data were available for 5723 patients with a median follow up of 2.5 years. The mean DRI was remarkably higher in the Eurotransplant region versus OPTN (1.71 versus 1.45), and this indicated different donor populations. Nevertheless, we were able to validate the DRI for the Eurotransplant region. Kaplan-Meier curves per DRI category showed a significant correlation between the DRI and outcomes (P < 0.001). A multivariate analysis demonstrated that the DRI was the most significant factor influencing outcomes (P < 0.001). Among all donor, transplant, and recipient variables, the DRI was the strongest predictor of outcomes.

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.