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

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.

No need for fasting prior to doppler ultrasound of pediatric liver transplants: A self-controlled study

BACKGROUND

Children frequently undergo routine Doppler-ultrasound (DUS) after liver transplantation (LT) for which they are fasted, but this may cause hunger and discomfort.

OBJECTIVE

To determine if DUS measurements, with focus on the portal vein (PV), are affected by prandial changes, and if this affects distress and feasibility of the DUS.

MATERIALS AND METHODS

Children were prospectively included to undergo a pre- and postprandial DUS on the same day at 6 months after LT. Pre- and anastomotic PV peak systolic velocity (PSV), and hepatic artery and hepatic vein DUS measurements were obtained. Pre- and postprandial measurements, and relative postprandial change of PV velocity ratio (VR) compared to PV anastomotic PSV, were compared using paired-sample t-tests and intraclass correlation coefficients (ICC). Obscuration by bowel gas, difficulty of DUS, and impact of fasting were assessed using 5-point rating scales.

RESULTS

Twenty-eight children (median age 3.5 years, IQR 1.6-10.8) were included; four were subsequently excluded because they were not fasted (N = 2) or withdrew consent for the second DUS (N = 2). Measurements between pre- and postprandial DUS, and relative postprandial change of VR compared to PV anastomotic PSV, were not significantly different (p > .05). Test consistency was good (ICC = 0.69, 95% CI = 0.29-0.67) for PV anastomotic PSV, and excellent (95% CI = 0.61-0.93) for PV VR. Obscuration by bowel gas or ease of DUS did not change after eating (p > .05). The majority (16/28, 57.2%) found fasting difficult, and several (13/28, 46.4%) got upset when fasted.

CONCLUSION

Children with an LT do not need to be fasted for routine DUS, which may decrease the burden of the examination.

Utilization of Segmental Grafts Is Associated With Higher Transplant Rates in Pediatric Patients

INTRODUCTION

In July 2017, a policy to increase the use of segmental grafts (SGs) was implemented at our institution. The aim was to compare changes in waitlist activity after implementation of this policy.

METHODS

A single-center, retrospective study. Pediatric patients on the liver waiting list between January 2015 and December 2019 were screened. Patients were classified as receiving a liver transplant (LT) before (Period 1) or after (Period 2) policy changes. Primary end points were transplant rates and time to transplant.

RESULTS

Sixty five first LT performed on 65 patients were included. Twenty nine LT were performed during Period 1 and 36 during Period 2. More than half (55%) of LT in Period 2 were SG, compared to 10.3% in Period 1 (P < 0.001). Forty nine and 56 pediatric candidates on the waiting list accounted for 38.78 and 24.48 person-years during Period 1 and Period 2, respectively. Transplant rates per 100 person-years on the waiting list increased from 85.09 during Period 1 to 187.87 in Period 2 (Rate ratio: 2.20; P < 0.001). Median time to receive a LT decreased from 229 d in Period 1 to 75 d during Period 2 (P = 0.013). One-year patient survival rates were 96.6% in Period 1 and 95.7% in Period 2. One-year graft survival rates were 89.7% and 88% in Period 1 and Period 2, respectively.

CONCLUSIONS

A policy to increase the use of SG was associated with significantly higher transplant rates and lower waiting times. Implementation of this policy can be done successfully with no observed negative impact on patient and graft survival.

International Liver Transplantation Society Global Census: First Look at Pediatric Liver Transplantation Activity Around the World

BACKGROUND

Over 16 000 children under the age of 15 died worldwide in 2017 because of liver disease. Pediatric liver transplantation (PLT) is currently the standard of care for these patients. The aim of this study is to describe global PLT activity and identify variations between regions.

METHODS

A survey was conducted from May 2018 to August 2019 to determine the current state of PLT. Transplant centers were categorized into quintile categories according to the year they performed their first PLT. Countries were classified according to gross national income per capita.

RESULTS

One hundred eight programs from 38 countries were included (68% response rate). 10 619 PLTs were performed within the last 5 y. High-income countries performed 4992 (46.4%) PLT, followed by upper-middle- (4704 [44·3%]) and lower-middle (993 [9·4%])-income countries. The most frequently used type of grafts worldwide are living donor grafts. A higher proportion of lower-middle-income countries (68·7%) performed ≥25 living donor liver transplants over the last 5 y compared to high-income countries (36%; P = 0.019). A greater proportion of programs from high-income countries have performed ≥25 whole liver transplants (52.4% versus 6.2%; P = 0.001) and ≥25 split/reduced liver transplants (53.2% versus 6.2%; P < 0.001) compared to lower-middle-income countries.

CONCLUSIONS

This study represents, to our knowledge, the most geographically comprehensive report on PLT activity and a first step toward global collaboration and data sharing for the greater good of children with liver disease; it is imperative that these centers share the lead in PLT.

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.

Biliary complications following split liver transplantation in adult recipients: a matched pair analysis on single-center experience

The utilization of split liver grafts can increase access to liver transplantation (LT) for adult patients, particularly when liver grafts are shared between 2 adult recipients. However, it is yet to be determined whether split liver transplantation (SLT) increases the risk of biliary complications (BCs) compared with whole liver transplantation (WLT) in adult recipients. This retrospective study enrolled 1441 adult patients who underwent deceased donor LT at a single-site between January 2004 and June 2018. Of those, 73 patients underwent SLTs. Graft type for SLT includes 27 right trisegment grafts, 16 left lobes, and 30 right lobes. A propensity score matching analysis selected 97 WLTs and 60 SLTs. Biliary leakage was more frequently seen in SLTs (13.3% vs. 0%; p <0.001), whereas the frequency of biliary anastomotic stricture was comparable between SLTs and WLTs (11.7% vs. 9.3%; p=0.63). Graft and patient survival rates of patients undergoing SLTs were comparable to those undergoing WLTs (p=0.42 and 0.57, respectively). In the analysis of the entire SLT cohort, BCs were seen in 15 patients (20.5%) including biliary leakage in 11 patients (15.1%) and biliary anastomotic stricture in 8 patients (11.0%) [both in 4 patients (5.5%)]. The survival rates of recipients who developed BCs were significantly inferior to those without BCs (p <0.01). By multivariate analysis, the split grafts without common bile duct increased the risk of BCs. In conclusion, SLT increases the risk of biliary leakage compared with WLT. Biliary leakage can still lead to fatal infection and thus should be managed appropriately in SLT.

An appraisal of technical variant grafts compared to whole liver grafts in pediatric liver transplant recipients: Multicenter analysis from the SPLIT registry

BACKGROUND

Shortages of liver allografts for children awaiting transplantation have led to high LT waitlist mortality. Prior studies have shown that usage of TVG can reduce waiting time and waitlist mortality, but their use is not universal. We sought to compare patient and graft survival between WLG and TVG and to identify potential associated risk factors in a contemporary pediatric LT cohort.

METHODS

We performed a retrospective analysis of patient survival, graft survival, and biliary and vascular complications for LT recipients <18 years old entered into the Society of Pediatric Liver Transplantation prospective multicenter database.

RESULTS

Of 1839 LT recipients, 1029 received a WLG and 810 received a TVG from either a LD or a DD. There was no difference in patient survival or graft survival by graft type. Three-year patient survival and graft survival were 96%, 93%, and 96%, and 95%, 89%, and 92% for TVG-LD, TVG-DD, and WLG, respectively. Biliary complications were more frequent in TVG. Hepatic artery thrombosis was more frequent in WLG. Multivariate analysis revealed primary diagnosis was the only significant predictor of patient survival. Predictors for graft survival included time-dependent development of biliary and vascular complications.

CONCLUSIONS

There were no significant differences in patient and graft survival based on graft types in this North American multi-center pediatric cohort. Widespread routine use of TVG should be strongly encouraged to decrease mortality on the waitlist for pediatric LT candidates.

Increased use of split liver grafts in adult recipients following implementation of a pediatric liver transplant program

BACKGROUND

Split liver transplantation (SLT) is a strategy to address organ shortage, but is a technically more demanding procedure than whole graft liver transplantation (LT). We aimed to determine the outcomes following SLT in adult recipients as well as to highlight the impact that having a pediatric LT program has on SLT implementation.

METHODS

All SLTs conducted at a single-center from 2010 to 2019 were identified. Patient data was obtained through retrospective review of the electronic medical record. Kaplan-Meier analysis assessed primary outcomes of 1-,3-, and 5-year graft and patient survival.

RESULTS

We identified 37 SLTs performed at our institution from 2010 to 2019. Twenty-four donated livers resulted in 21 extended right lobes and 16 left lateral segments for adults and pediatrics recipients, respectively. Eighty-one percent (30/37) of the SLTs were performed after introduction of the combined pediatric program in 2016. 13/24 donor livers were split with both grafts allocated and used at our institution and 92% occurred after introduction of the pediatric program. Graft survival rates at 1-, 3-, and 5-years were 94% in adult recipients and 100% for all time periods in pediatric recipients. Actuarial post-transplant patient survival was 100% at 1-, 3-, and 5-years in both.

CONCLUSIONS

The introduction of a pediatric liver transplantation program resulted in more than a fourfold increase in the number of SLTs performed at our center. Increase in allocation and use of both grafts at our institution was also seen.

Split liver transplantation with extended right grafts on adult recipients: A propensity score matching analysis

INTRODUCTION

Split liver transplantation (SLT) emerged due to its potential to contribute to the organ pool and reduce organ shortage. However, SLT is technically challenging and has been associated with higher rates of postoperative complications leading to concerns about graft and patient survival. Moreover, there are few studies on matched-pair adult recipients of SLT and whole-liver transplant (WLT), with conflicting results.

METHODS

This retrospective study analyze outcomes among adults who underwent SLT at our institution from 2010 to 2019. A 1:1 propensity score matching analysis was performed based on important donor and recipient variables. Baseline characteristics and postoperative outcomes were analyzed and compared between groups. Actuarial graft and patient survival were analyzed by KM curves.

RESULTS

Out of 592 adults receiving a LT in our institution, 21 SLT adult recipients were identified and matched with 21 adults undergoing WLT. As expected donor age was significantly lower in SLT recipients (16 (15-22) vs. 32 (17-47), P = .012). Additional donor characteristics, including anthropometrics, and ischemic times were similar between groups. Baseline recipient characteristics and postoperative outcomes, including length of stay, vascular complications, biliary complications, and re-transplantation were comparable between SLT and WLT recipients. Graft (95/95/95 vs. 100/94/94, P = .98) and patient (100/100/100 vs. 100/94/94, P = .30) survival at 1-, 3-, 5-years, were similar between the SLT- and WLT group, respectively.

CONCLUSION

Split liver transplantation has the potential to increase the availability of organs for adult recipients without compromising individual outcomes.

IV segment portal vein reconstruction in split-liver transplantation with extended right grafts

Background

Liver transplantation is one of the most effective treatments for end-stage liver disease. Split liver transplantation (SLT) can effectively improve the utilization efficiency of grafts. However, split liver transplantation still faces shortcomings and is not widely used in surgery. How to improve the effective transplantation volume of split liver transplantation and promote the postoperative recovery of patients has important clinical significance.

Methods

In our study, the donor’s liver was split into the extended right graft and left lateral sector, and the IV segment occur ischemia. To guarantee the functional graft size, and avoid complications, we reconstructed the IV segment portal vein and left portal vein. And we analyzed the operation time, intraoperative bleeding, liver function, and postoperative complications.

Results

In our research, 14 patients underwent IV segment portal vein reconstruction, and 8 patients did not undergo vascular reconstruction. We found that the ischemic area of the IV segment decreased significantly after IV segment portal vein reconstruction. We found that there was no significant difference in operation time and postoperative complications between the patients of the groups. There were significant differences in ALT on the 1st day and albumin on the 6th day after the operation.

Conclusion

It indicates that IV segment reconstruction in SLT surgery can alleviate the graft ischemic and promote the recovery of liver function after the operation. And, IV segment reconstruction as a novel operating procedure may be widely used in SLT.

Living Donor Liver Transplantation vs. Split Liver Transplantation Using Left Lateral Segment Grafts in Pediatric Recipients: An Analysis of the UNOS Database

Split and LDLT in pediatric patients have the potential to decrease wait times and waitlist mortality. Using UNOS-STAR data, we compared outcomes of pediatric patients undergoing LDLT and SLT using LLS grafts. The baseline characteristics and post-operative outcomes were compared between groups. Actuarial graft and patient survival were analyzed with Kaplan-Meier curves. Between 2010 and 2019, 911 pediatric LT were included in the analysis (LD graft group, n = 508, split graft group, n = 403). LD graft recipients spent more time on the waitlist vs. the split graft group (60 (22–138) days vs. 46 (16–108) days; p = 0.007). LD recipients had a lower rate of graft failure, found in 9.8% of patients compared with 14.6% in the split graft group (p = 0.02). HAT was the most common graft failure cause, with similar rates. Graft and patient survival at 1-, 3-, and 5-years was comparable between LDLT and SLT. In subgroup analyses, patients with biliary atresia, those ≤10 kg or ≤10 years old receiving an LD graft showed improved graft survival. In conclusion, LDLT is associated with a lower rate of graft failure in pediatric patients. The use of LLS regardless of the type of donor is a safe way to facilitate access to transplantation to pediatric patients with acceptable short and long-term outcomes.

An Update on Usage of High-Risk Donors in Liver Transplantation

The ideal management for end stage liver disease, acute liver failure, and hepatocellular carcinoma (HCC), within specific criteria, is liver transplantation (LT). Over the years, there has been a steady increase in the candidates listed for LT, without a corresponding increase in the donor pool. Therefore, due to organ shortage, it has been substantially difficult to reduce waitlist mortality among patients awaiting LT. Thus, marginal donors such as elderly donors, steatotic donors, split liver, and donors after cardiac death (DCD), which were once not commonly used, are now considered. Furthermore, it is encouraging to see the passing of Acts, such as the HIV Organ Policy Equity (HOPE) Act, enabling further research and development in utilizing HIV grafts. Subsequently, the newer antivirals have aided in successful post-transplant period, especially for hepatitis C positive grafts. However, currently, there is no standardization, and protocols are center specific in the usage of marginal donors. Therefore, studies with longer follow ups are required to standardize its use.

Ethics of split liver transplantation: should a large liver always be split if medically safe?

Split liver transplantation (SLT) provides an opportunity to divide a donor liver, offering transplants to two small patients (one or both could be a child) rather than keeping it whole and providing a transplant to a single larger adult patient. In this article, we attempt to address the following question that is identified by the Organ Procurement and Transplant Network and United Network for Organ Sharing: 'Should a large liver always be split if medically safe?' This article aims to defend an answer-'not always'-and clarify under what circumstances SLT is ethically desirable. Our answer will show why a more dynamic approach is needed to the ethics of SLT. First, we discuss a case that does not need a dynamic approach. Then, we explain what is meant by a dynamic approach and why it is needed.

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.

A Novel Surgical Technique to Assure Donor and Recipient Safety: Pyloric to Segment 4 Arterial Reconstruction

Background.

Strategies to extend the pool of organs include and promote the use of segmental liver grafts. While performing a living donor left lateral segment (LLS) liver transplant and in split procedures, the hepatic artery´s division becomes critical when a dominant segment 4 artery (S4A) emerges from the left hepatic artery (LHA). We aim to describe a novel technique that consists of performing microsurgical reconstruction from the pyloric artery (PA) to S4A.

Case Reports.

A 45-y-old living donor was evaluated to use his LLS as a graft for a pediatric recipient. During the procedure, a dominant S4A born from the LHA was dissected. To obtain an appropriate LHA length and diameter for the recipient, it was necessary to transect it. An extended right lobe split graft was used in a 61-y-old patient. The S4A born from LHA had to be sectioned during the split procedure. In both cases, segment 4 remained incompletely perfused. The PA was dissected with enough length to be rotated, to perform a microsurgical anastomosis to the S4A, recovering parenchyma’s color and Doppler signal while vascular permeability was demonstrated using CT scan. There was no biliary or cut surface complication.

Conclusions.

PA to S4A reconstruction is a simple and novel technique that can be used for LLS and extended right lobe split graft and might contribute to increase donor selection and reduce living donor and recipient S4A-related complications.

Explorative study of serum biomarkers of liver failure after liver resection

Conventional biochemical markers have limited usefulness in the prediction of early liver dysfunction. We, therefore, tried to find more useful liver failure biomarkers after liver resection that are highly sensitive to internal and external challenges in the biological system with a focus on liver metabolites. Twenty pigs were divided into the following 3 groups: sham operation group (n = 6), 70% hepatectomy group (n = 7) as a safety margin of resection model, and 90% hepatectomy group (n = 7) as a liver failure model. Blood sampling was performed preoperatively and at 1, 6, 14, 30, 38, and 48 hours after surgery, and 129 primary metabolites were profiled. Orthogonal projection to latent structures-discriminant analysis revealed that, unlike in the 70% hepatectomy and sham operation groups, central carbon metabolism was the most significant factor in the 90% hepatectomy group. Binary logistic regression analysis was used to develop a predictive model for mortality risk following hepatectomy. The recommended variables were malic acid, methionine, tryptophan, glucose, and γ-aminobutyric acid. Area under the curve of the linear combination of five metabolites was 0.993 (95% confidence interval: 0.927–1.000, sensitivity: 100.0, specificity: 94.87). We proposed robust biomarker panels that can accurately predict mortality risk associated with hepatectomy.

Donor-to-recipient weight ratio is a risk factor for hepatic artery thrombosis after whole-liver transplantation in children under 25 kg

Hepatic artery thrombosis (HAT) following pediatric liver transplantation increases morbidity and risk of graft failure. We performed a retrospective chart review of all patients who underwent deceased-donor liver transplantation from August 2002 to July 2016. Multi-organ transplant recipients were excluded. We examined the incidence of HAT at our institution and sought to identify associated donor or recipient risk factors. A total of 127 deceased-donor liver transplant patients with a median age of 1.7 years (IQR 0.67-6.7) were identified. Of those, 14 developed HAT, all weighing under 25 kg. Among 100 patients under 25 kg, whole-liver graft recipients had an odds ratio of 3.98 (95% confidence interval [CI]: 1.03, 15.34; P = .045) for developing HAT compared with split-liver graft recipients. Within the whole-liver recipient group under 25 kg, 11 patients developed HAT with a median donor-to-recipient ratio (DRWR) of 0.9 (IQR: 0.7-1.2) compared with a median DRWR of 1.4 (IQR: 1.1-1.9) for those who did not develop HAT. Multivariate analysis showed DRWR to be an independent risk factor for HAT in patients weighing under 25 kg who received whole organ grafts, with an odds ratio of 3.89 (95% CI: 1.43, 10.54; P = .008) for each 0.5 unit decrease in DRWR. Our results suggest that in recipients under 25 kg 1) split-liver grafts may have a lower rate of HAT and 2) selecting whole organ donors with a higher DRWR may decrease the incidence of HAT.

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.

Split Liver Transplantation and Pediatric Waitlist Mortality in the United States: Potential for Improvement

BACKGROUND

In the United States, 1 in 10 infants and 1 in 20 older children die on the liver transplant waiting list. Increasing split liver transplantation could increase organ availability for these children, without decreasing transplants in adults.

METHODS

Using United Network for Organ Sharing Standard Transplant Analysis and Research data, we identified livers transplanted 2010 to 2015 that could potentially have been used for split transplant, based on strict criteria. Livers not suitable for pediatric patients or allocated to high-risk recipients were excluded. Number and distribution of potentially "split-able" livers were compared to pediatric waitlist deaths in each region.

RESULTS

Of 37 333 deceased donor livers transplanted, 6.3% met our strict criteria for utilization in split liver transplant. Only 3.8% of these were actually utilized for split liver transplantation. 96% were used for a single adult recipient. Of the 2253 transplanted as whole livers, 82% of their recipients were listed as willing to accept a segmental liver, and only 3% were listed as requiring a cold ischemia time less than 6 hours. Over the same 5 years, 299 children died on the waitlist. In every United Network for Organ Sharing region, there were more potentially "split-able" livers than pediatric waitlist deaths. Thirty-seven percent of pediatric waitlist deaths occurred at transplant centers that averaged 1 or less pediatric split liver transplantation annually during the study period.

CONCLUSIONS

This comparison, although not conclusive, suggests that we might be missing opportunities to reduce pediatric waitlist mortality without decreasing access for adults-using split liver transplant. Barriers are significant, but further work on strategies to increase split liver transplant is warranted.

Split liver transplantation: Current developments

In 1988, Rudolf Pichlmayr pioneered split liver transplantation (SLT), enabling the transplantation of one donor liver into two recipients - one pediatric and one adult patient. In the same year, Henri Bismuth and colleagues performed the first full right/full left split procedure with two adult recipients. Both splitting techniques were rapidly adopted within the transplant community. However, a SLT is technically demanding, may cause increased perioperative complications, and may potentially transform an excellent deceased donor organ into two marginal quality grafts. Thus, crucial evaluation of donor organs suitable for splitting and careful screening of potential SLT recipients is warranted. Furthermore, the logistic background of the splitting procedure as well as the organ allocation policy must be adapted to further increase the number and the safety of SLT. Under defined circumstances, in selected patients and at experienced transplant centers, SLT outcomes can be similar to those obtained in full organ LT. Thus, SLT is an important tool to reduce the donor organ shortage and waitlist mortality, especially for pediatric patients and small adults. The present review gives an overview of technical aspects, current developments, and clinical outcomes of SLT.

In situ liver splitting under extracorporeal membrane oxygenation in brain-dead donor

Hemodynamic instability is generally considered as a contraindication to liver splitting, in particular when using an in situ technique. We describe the cases of two young donors with brain death in whom refractory cardiac arrest and hemodynamic instability were supported by veno-arterial extracorporeal membrane oxygenation (VA-ECMO), allowing uneventful in situ splitting. Two adult and two pediatric liver recipients were successfully transplanted with immediate graft function. Favorable outcomes were also observed for the other transplanted organs, including one heart, two lungs, and four kidneys. Refractory cardiac arrest and hemodynamic instability corrected by VA-ECMO should not be considered as a contraindication to in situ liver splitting.