Current status of deceased donor split liver transplantation in Japan

Improved survival of pediatric deceased donor liver transplantation recipients after introduction of the pediatric prioritization system: Analysis of data from a Japanese national survey

BACKGROUND

In Japan, there has never been a national analysis of pediatric deceased donor liver transplantation (pDDLT) based on donor and recipient factors. We constructed a Japanese nationwide database and assessed outcomes of pDDLT focusing on the pediatric prioritization system introduced in 2018.

METHODS

We collected data on pDDLTs (<18 years) performed between 1999 and 2021 from the Japan Organ Transplant Network and Japanese Liver Transplantation Society, identified risk factors for graft survival and compared the characteristics and graft survival in pDDLTs conducted before and after the introduction of the pediatric prioritization system.

RESULTS

Overall, 112 cases of pDDLT were included, with a 1-year graft survival rate of 86.6%. Four poor prognostic factors were identified: recipient intensive care unit stay, model for end-stage liver disease/pediatric end-stage liver disease score, donor cause of death, and donor total bilirubin. After the introduction of the system, allografts from pediatric donors were more reliably allocated to pediatric recipients and the annual number of pDDLTs increased. The 1-year graft survival rate improved significantly as did pDDLT conditions indicated by the risk factors.

CONCLUSIONS

Under the revised allocation system, opportunities for pDDLT increased, resulting in favorable recipient and donor conditions and improved survival.

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.

Current status of pediatric deceased donor liver transplantation: Lessons learned from a high-volume center in Japan where living donation remains predominant

BACKGROUND

In Japan, a recent gradual increase in deceased donor donation has expanded opportunities for pediatric patients to obtain deceased grafts.

METHODS

Forty-three children underwent deceased donor liver transplantation (DDLT) at our institute before February 2020. Twenty-five patients received a split or reduced graft and 18 patients received a whole graft. The clinical outcomes of DDLT were retrospectively analyzed.

RESULTS

The main organ resource was split/reduced grafts retrieved from adult donors; however, the number of whole grafts retrieved from pediatric donors has increased. The rates of major complications were similar in the two groups. The 5-year graft survival rate of patients who received a split/reduced graft (78.0%) was lower than that of patients who received a whole graft (88.9%; P = .40). The 3-year graft survival rates of patients who recently received a split/reduced graft and a whole graft improved to 92.3% and 91.7%, respectively.

CONCLUSIONS

The recent amendment of the organ allocation system, especially the introduction of pediatric prioritization, can effectively increase the chance to obtain deceased donor grafts for pediatric DDLT in Japan. The recent refinements in donor and recipient selection and in the surgical technique of split DDLT can improve the outcomes of pediatric DDLT in Japan.

Waiting list mortality for pediatric deceased donor liver transplantation in a Japanese living-donor-dominant program

Living donor liver transplantation (LDLT) has become a major life-saving procedure for children with end-stage liver disease in Japan, whereas deceased donor liver transplantation (DDLT) has achieved only limited success. The annual number of pediatric liver transplantations is approximately 100-120, with a patient 20-year survival rate of 81.0%. In 2005, the liver transplantation program at the National Center for Child Health and Development in Tokyo, Japan, was initiated, with an overall number of 560 pediatric patients with end-stage liver disease to date. In July 2010, our center was qualified as a pediatric DDLT center; a total of 132 patients were listed for DDLT up until February 2019. The indications for DDLT included acute liver failure (n = 46, 34.8%), metabolic liver disease (n = 26, 19.7%), graft failure after LDLT (n = 17, 12.9%), biliary atresia (n = 16, 12.1%), and primary sclerosing cholangitis (n = 10, 7.6%). Overall, 25.8% of the patients on the waiting list received a DDLT and 52.3% were transplanted from a living donor. The 5-year patient and graft survivals were 90.5% and 88.8%, respectively, with an overall waiting list mortality of 3.0%. LDLT provides a better survival compared with DDLT among the recipients on the DDLT waiting list. LDLT is nevertheless of great importance in Japan; however, it cannot save all pediatric recipients. As the mortality of children on the waiting list has not yet been reduced to zero, both LDLT and DDLT should be implemented in pediatric liver transplantation programs.

Feasibility and Safety of Split-Liver Transplantation in a Nascent Framework of Deceased Donation

Split-liver transplantation (SLT) is a valuable option for optimizing the use of good-quality deceased donor grafts. It is not routinely reported outside the West because of limited deceased donor numbers, technical and organizational constraints, lack of experience, and a predominant living donor liver transplantation (LDLT) practice. At our center, 20% of the liver transplantations (LTs) are from deceased donors. We report our experience of SLT and compare outcomes with pediatric and adult LDLT recipients. A prospectively maintained database of all LT recipients between September 2009 and March 2017 was analyzed. Each pediatric SLT recipient was matched to 2 pediatric LDLT recipients for age, weight, urgency, and year of transplant. Each adult SLT recipient was similarly matched to 2 adult LDLT recipients for age, Model for End-Stage Liver Disease score, and year of transplant. Intraoperative and postoperative parameters, including recovery time, morbidity (biliary and vascular complications, Clavien grade >IIIA complications), and mortality were compared. In total, 40 SLTs were performed after splitting 20 deceased donor livers (in situ, n = 11; hybrid split, n = 3; and ex vivo, n = 6). Recipients included 22 children and 18 adults. There were 18 livers that were split conventionally (extended right lobe and left lateral segment [LLS]), and 2 were right lobe-left lobe SLTs. Also, 3 LLS grafts were used as auxiliary grafts for metabolic liver disease. Perioperative mortality in SLT recipients occurred in 3 patients (2 children and 1 adult). Incidence of vascular, biliary, and Clavien grade >IIIA complications were similar between matched adult and pediatric SLT and LDLT groups. In conclusion, SLT is an effective technique with outcomes comparable to living donor grafts for adult and pediatric recipients. Using SLT techniques at centers with limited deceased donors optimizes the use of good-quality whole grafts and reduces the gap between organ demand and availability.

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.

Current status of pediatric transplantation in Japan

Brain-dead donor organ transplantation has been available to children in Japan since the 2010 revision of the Organ Transplant Law. Of the 50–60 brain-dead donor organ transplants performed annually in Japan, however, very few (0–4 per year) are performed in children. Again, while those receiving liver, heart, and kidney transplants are reported to fare better than their counterparts in the rest of the world, organ shortage is becoming a matter of great concern. Very few organs become available from brain-dead donors or are transplanted to adults if made available at all, with some children dying while on the brain-dead organ waiting list. Against this background, living-donor transplants, split-liver transplants, domino transplants, and hepatocyte transplants represent alternative modalities, each of which is shown to be associated with favorable outcomes. Challenges exist, include streamlining the existing framework for promoting organ donation for children and between children.

Liver transplantation in Japan

As of December 31, 2014, 7937 liver transplants (7673 living donor transplants and 264 deceased donor liver transplantations [DDLTs; 261 from heart-beating donors and 3 from non-heart-beating donors]) have been performed in 67 institutions in Japan. The revised Organ Transplant Law in Japan came into effect in July 2010, which allows organ procurement from brain-dead individuals, including children, with family consent if the patient had not previously refused organ donation. However, the number of deceased donor organ donations has not increased as anticipated. The rate of deceased organ donations per million population (pmp) has remained at less than 1. To maximize the viability of the limited numbers of donated organs, a system has been adopted that includes the partnership of well-trained transplant consultant doctors and local doctors. For compensating for the decreased opportunity of on-site training, an educational system regarding quality organ procurement for transplant surgeons has also been established. Furthermore, experts in the field of liver transplantation are currently discussing adoption of the Model for End-Stage Liver Disease score for allocation, promoting split-liver transplantation, arranging in-house coordinators, and improving the frequency of proposing the option to donate organs to the families. To overcome the shortage of donors during efforts to promote organ donation, living donor liver transplantation (LDLT) has been developed in Japan. Continuous efforts to increase DDLT in addition to the successful experience of LDLT will increase the benefits of liver transplantation for more patients. Liver Transplantation 22 1401-1407 2016 AASLD.

Efficacy of recombinant thrombomodulin for DIC after deceased donor liver transplantation: a case report

BACKGROUND

Disseminated intravascular coagulation (DIC) after liver transplantation (LT) is a difficult complication. We report a case of disseminated intravascular coagulation after deceased donor liver transplantation (DDLT) treated with recombinant thrombomodulin (rTM).

CASE PRESENTATION

A 30-year-old woman underwent right tri-segment split graft DDLT for acute liver failure. She developed disseminated intravascular coagulation on post-operative day 5 with fever. Computed tomography revealed necrosis of hepatic segment IV, and her acute-phase disseminated intravascular coagulation score was seven points. She was given rTM, and the inflammation, liver function, and coagulation disorders immediately improved. However, pleural effusion drainage from the chest tube became bloody on post-operative day 11, and rTM was discontinued. She progressed well and was discharged from the hospital on post-operative day 28. rTM is an effective treatment for disseminated intravascular coagulation; however, rTM for cases with coagulation disorders, which can occur after liver transplantation, has both risks and benefits.

CONCLUSIONS

We report a case of DIC after LT, in which rTM was potentially effective. Further studies are needed to determine the appropriate dosages, duration, and additional considerations for rTM therapy in liver transplantation patients.