Long-term results after transplantation of pediatric liver grafts from donation after circulatory death donors

Long-term outcomes and health-related quality of life 20 years after pediatric liver transplantation

Pediatric liver transplantation is a challenging surgical procedure requiring complex post-transplant patient management. Liver transplantation in children should ensure long-term survival and good health-related quality of life (HR-QOL), but data in the literature are conflicting. With the aim of investigating survival and psychosocial outcomes of patients transplanted during childhood, we identified 40 patients with ≥ 20-year follow-up after liver transplantation regularly followed up at our Institution. Clinical charts were reviewed to retrieve patients' data. Psychosocial aspects and HR-QOL were investigated by an in-person or telephonic interview and by administering the WHOQOL-BREF questionnaire through an online form. Ten- and 20-year patient survival was 97.5% (95% CI 92.8-100%), whereas 10- and 20-year graft survival was 77.5% (65.6-91.6%) and 74.8% (62.5-89.6%), respectively. At last follow-up visit, 31 patients (77.5%) were receiving a tacrolimus-based immunosuppression. Twelve (32.4%) patients obtained a university diploma or higher, whereas 19 (51.4%) successfully completed high school. 81.1% of patients were active workers or in education, 17.5% had children, and 35% regularly practiced sport. 25 patients answered to the WHOQOL-BREF questionnaire. More than 60% of respondents did not report any disability and the perceived physical status was invariably good or very good. Median scores for physical health, psychological health, social relationships, and environment were 16.6, 14.7, 16, and 15, respectively. Pediatric liver transplantation is associated with excellent long-term survival and good HR-QOL. Psychological health and environment represent areas in which support would be needed to further improve HR-QOL.

Development and validation of a nomogram model for predicting chronic kidney disease after liver transplantation: a multi-center retrospective study

Chronic kidney disease (CKD) is a frequent complication after liver transplantation (LT) and associated with poor prognosis. In this study, we retrospectively analyzed 515 adult patients who underwent LT in our center. They were randomly divided into a training set (n = 360) and an internal test set (n = 155). Another 118 recipients in other centers served as external validation set. Univariate and multivariate COX regression analysis were used to determine risk factors. A nomogram model was developed to predict post-LT CKD. The incidence of post-LT CKD in our center was 16.9% (87/515) during a median follow-up time of 22.73 months. The overall survival of recipients with severe CKD (stage IV and V) were significantly lower than those with non or mild CKD (stage III) (p = 0.0015). A nomogram model was established based on recipient's age, anhepatic phase, estimated glomerular filtration rate and triglyceride levels at 30 days after LT. The calibration curves for post-LT CKD prediction in the nomogram were consistent with the actual observation in both the internal and external validation set. In conclusion, severe post-LT CKD resulted in a significantly reduced survival in liver recipient. The newly established nomogram model had good predictive ability for post-LT CKD.

Use of DCD organs: Expanding the donor pool to increase pediatric transplantation

The number of children being listed for transplant continues to be greater than the number of available organs. In fact, over the past decade, rates of liver and kidney transplants in pediatric transplantation are essentially unchanged (Am J Transplant. 2020;20:193 and Am J Transplant. 2020;20:20). The use of DCD donors offers a potential solution to organ scarcity; however, the use of DCD organs in pediatric transplantation remains a rare event. Pediatric transplants done using carefully chosen DCD donor organs have shown to have outcomes similar to those seen with the use of donation after brain death (DBD) donors. Herein, we review the literature to examine the utilization of DCD livers and kidneys, outcomes of these allografts, and assess if DCD organs are a viable method to increase organ availability in pediatric transplantation.

Donation after Circulatory Death Liver Transplantation in Paediatric Recipients

Waiting list mortality together, with limited availability of organs, are one of the major challenges in liver transplantation (LT). Especially in the paediatric population, another limiting factor is the scarcity of transplantable liver grafts due to additional concerns regarding graft size matching. In adults, donation after circulatory death (DCD) liver grafts have been used to expand the donor pool with satisfactory results. Although several studies suggest that DCD livers could also be used in paediatric recipients with good outcomes, their utilisation in children is still limited to a small number of reports. Novel organ perfusion strategies could be used to improve organ quality and help to increase the number of DCD grafts utilised for children. With the current manuscript, we present the available literature of LT using DCD grafts in paediatric recipients, discussing current challenges with the use of these livers in children and how machine perfusion technologies could be of impact in the future.

Recommendations for Donor and Recipient Selection and Risk Prediction: Working Group Report From the ILTS Consensus Conference in DCD Liver Transplantation

Although the utilization of donation after circulatory death donors (DCDs) for liver transplantation (LT) has increased steadily, much controversy remains, and no common acceptance criteria exist with regard to donor and recipient risk factors and prediction models. A consensus conference was organized by International Liver Transplantation Society on January 31, 2020, in Venice, Italy, to review the current clinical practice worldwide regarding DCD-LT and to develop internationally accepted guidelines. The format of the conference was based on the grade system. International experts in this field were allocated to 6 working groups and prepared evidence-based recommendations to answer-specific questions considering the currently available literature. Working group members and conference attendees served as jury to edit and confirm the final recommendations presented at the end of the conference by each working group separately. This report presents the final statements and recommendations provided by working group 2, covering the entire spectrum of donor and recipient risk factors and prediction models in DCD-LT.

Should We Be Utilizing More Liver Grafts From Pediatric Donation After Circulatory Death Donors? A National Analysis of the SRTR from 2002 to 2017

BACKGROUND

Rates of withdrawal of life-sustaining treatment are higher among critically ill pediatric patients compared to adults. Therefore, livers from pediatric donation after circulatory death (pDCD) could improve graft organ shortage and waiting time for listed patients. As knowledge on the utilization of pDCD is limited, this study used US national registry data (2002-2017) to estimate the prognostic impact of pDCD in both adult and pediatric liver transplant (LT).

METHODS

In adult LT, the short-term (1-year) and long-term (overall) graft survival (GS) between pDCD and adult donation after circulatory death (aDCD) grafts was compared. In pediatric LT, the short- and long-term prognostic outcomes of pDCD were compared with other type of grafts (brain dead, split, and living donor).

RESULTS

Of 80 843 LTs in the study, 8967 (11.1%) were from pediatric donors. Among these, only 443 were pDCD, which were utilized mainly in adult recipients (91.9%). In adult recipients, short- and long-term GS did not differ significantly between pDCD and aDCD grafts (hazard ratio = 0.82 in short term and 0.73 in long term, both P > 0.05, respectively). Even "very young" (≤12 y) pDCD grafts had similar GS to aDCD grafts, although the rate of graft loss from vascular complications was higher in the former (14.0% versus 3.6%, P < 0.01). In pediatric recipients, pDCD grafts showed similar GS with other graft types whereas waiting time for DCD livers was significantly shorter (36.5 d versus 53.0 d, P < 0.01).

CONCLUSIONS

Given the comparable survival seen to aDCDs, this data show that there is still much scope to improve the utilization of pDCD liver grafts.

Donation after circulatory death liver transplantation: What are the limits for an acceptable DCD graft?

The utilization of donation after circulatory death (DCD) livers has been growing over the last decade. In large-volume centers, survival outcomes have improved and are comparable to outcomes with brain death donor (DBD) liver transplantation (LT). The relatively concentrated success with DCD LT demonstrated by high-volume transplant centers has rekindled international enthusiasm. The combination of increasing expertise in DCD LT and ongoing shortage in transplantable organs has promoted expansion of the DCD donor pool with regards to donor age, body mass index and donor warm ischemia time. In this review, we focused on the practice patterns in DCD liver graft utilization in the last decade, along with the possibilities for further expansion of DCD liver graft utilization and new technologies, such as machine perfusion.

First pediatric organ donation after circulatory determination of death in Singapore: Facing challenges in the absence of a local practice guideline

Pediatric organ donation represents only a low proportion of overall organ donation in many parts of world, unable to match the needs for pediatric organ transplantation. Pediatric organ donation after circulatory determination of death (DCD) is increasingly explored in pediatric transplantation, as it increases the availability of organ grafts. A 6-year-old Caucasian boy with a history of arteriovenous malformation presented with a catastrophic intracranial bleed, resulting in severe brainstem dysfunction despite maximal medical and surgical measures. He did not fulfill the criteria for brain death, which must be met for pediatric organ donation in Singapore. Due to parental request, his organs were donated after withdrawal of life support and determination of death by circulatory criteria. Pediatric organ DCD poses many challenges in the pediatric population, especially in the absence of a local practice guideline. We present the first case of a pediatric organ DCD that has occurred in Singapore. Further work is needed, particularly in establishing a national policy for pediatric organ DCD and increasing overall awareness and acceptance toward pediatric organ donations.

Livers From Pediatric Donation After Circulatory Death Donors Represent a Viable and Underutilized Source of Allograft

Despite increased numbers of donation after circulatory death (DCD) donors, pediatric DCD livers are underused. To investigate possible reasons for this discrepancy, we conducted a retrospective cohort study using 2 data sets from the Organ Procurement and Transplantation Network for all deceased liver donors and for all recipients of DCD liver transplants from March 8, 1993, to June 30, 2018. Pediatric (0-12 years) and adolescent (13-17 years) DCD donors were compared with those aged 18-40 years. We found that pediatric DCD allografts are recovered at a significantly lower rate than from 18-to-40-year-old donors (27.3% versus 56.3%; P < 0.001). However, once recovered, these organs are transplanted at a similar rate to those from the 18-to-40-year-old donor cohort (74.7% versus 74.2%). Significantly more pediatric DCD livers (odds ratio [OR], 3.75; confidence interval [CI], 3.14-4.47) were not recovered compared with adult organs, which were most commonly not recovered due to organ quality (10.2% versus 7.1%; P < 0.001). The 10-year relative risks (RRs) for graft failure and patient death were similar between pediatric and adult DCD donors, with adolescent DCD livers demonstrating improved outcomes. DCD livers transplanted into pediatric donors were protective against graft failure (RR, 0.46; 95% confidence interval [CI], 0.21-0.99) and patient death (RR, 0.16; 95% CI, 0.04-0.69). In conclusion, despite lower rates of recovery, pediatric DCD livers represent a viable organ source for certain adults and children.

First report of successful transplantation of a pediatric donor liver graft after hypothermic machine perfusion

One of the main limiting factors in pediatric liver transplantation is donor availability. For adults, DCD liver grafts are increasingly used to expand the donor pool. To improve outcome after DCD liver transplantation, ex situ machine perfusion is used as an alternative organ preservation strategy, with the supplemental value of providing oxygen to the graft during preservation. We here report the first successful transplantation of a pediatric DCD liver graft after hypothermic oxygenated machine perfusion. The full-size liver graft was derived from a 13-year-old, female DCD donor and was end-ischemic pretreated with dual hypothermic oxygenated machine perfusion. Arterial and portal pressures were set at 18 and 4 mm Hg, slightly lower than protocolized settings for adult livers. During 2 hours of machine perfusion, portal and arterial flows increased from 100 to 210 mL/min and 30 to 63 mL/min, respectively. The pretreated liver graft was implanted in a 16-year-old girl with progressive familial intrahepatic cholestasis type 2. Postoperative AST, ALT, and prothrombin time normalized within a week. The recipient quickly recovered and was discharged from the hospital after 18 days. One year after transplantation, she is in excellent condition with a completely normal liver function and histology. This case is the first report of successful transplantation of a pediatric DCD liver graft after hypothermic oxygenated machine perfusion and illustrates the potential role of ex situ machine perfusion in expanding the donor pool and improving outcome after pediatric liver transplantation.

Pediatric donation after circulatory determination of death (pDCD): A narrative review

Pediatric donation after circulatory death (pDCD) is an established pathway for organ donation. It remains, however, a relatively rare event worldwide, and most clinicians outside of the pediatric intensive care unit (PICU) are unfamiliar with it. The goal of this review is to introduce the processes and concepts of pDCD. While most children die in circumstances that would not allow pDCD, many children that die after withdrawal of life sustaining therapy (WLST) may be eligible for donation of some organs. The potential benefits of this practice to patients on the wait list are well known, but donation can also be an opportunity to honor a patient's or family's desire to altruistically improve the lives of others. Offering the possibility of donation requires careful attention to ethical principles to ensure that conflicts of interest are avoided and that the family is free to make an independent, fully informed decision. Doing so allows families and decision makers the autonomy to decide if donation is something they wish to incorporate into end-of-life care.

Prediction of rat liver transplantation outcomes using energy metabolites measured by microdialysis

BACKGROUND

Warm ischemia jeopardizes graft quality and recipient survival in donation after cardiac death (DCD) transplantation. Currently, there is no system to objectively evaluate the liver quality from DCD. The present study tried to use energy metabolites to evaluate the donor liver quality.

METHODS

We divided 195 Sprague-Dawley rats into five groups: the control (n = 39), warm ischemic time (WIT) 15 min (n = 39), WIT 30 min (n = 39), WIT 45 min (n = 39), and WIT 60 min (n = 39) groups. Three rats from each group were randomly selected for pretransplant histologic evaluation of warm ischemia-related damage. The remaining 36 rats were randomly divided into donors and recipients of 18 liver transplantations, and were subjected to postoperative liver function and survival analyses. Between cardiac arrest and cold storage, liver energy metabolites including glucose, lactate, pyruvate, and glycerol were measured by microdialysis. The lactate to pyruvate ratio (LPR) was calculated.

RESULTS

The changes in preoperative pathology with warm ischemia were inconspicuous, but the trends in postoperative pathology and aminotransferase levels were consistent with preoperative energy metabolite measurements. The 30-day survival rates of the control and WIT 15, 30, 45, and 60 min groups were 100%, 81.82%, 76.92%, 58.33%, and 25.00%, respectively. The areas under the receiver operating characteristic curves of glucose, lactate, glycerol, and LPR were 0.87, 0.88, 0.88, and 0.92, respectively.

CONCLUSION

Glucose, lactate, glycerol, and LPR are predictors of graft quality and survival outcomes in DCD transplantation.

Liver Transplantation Today: Where We Are Now and Where We Are Going

Liver transplantation was made a reality through the bravery, innovation, and persistence of Dr. Thomas Starzl. His death in 2017, at the age of 90, makes us pause to consider how far the field has come since its inception by this remarkable pioneer. It also is an opportunity to evaluate the continued novel innovations which contribute to the growth and potential for liver transplantation in the future. The liver transplant community in 2017 continued to be most significantly challenged by an overwhelming disparity between the need for liver transplant and the shortage of donor organs. The many ways in which this critical shortage are being addressed are examined in this article. The continued debate about equitable and efficacious organ allocation, "the liver wars," has dominated much of the recent past, while efforts to optimize current organ availability have also been aggressively pursued. Efforts to optimize the use of marginal and expanded criteria organs have escalated in recent years and have been accompanied by rigorous scientific evaluation. The ongoing opioid epidemic, combined with the approval and availability of highly effective hepatitis C treatment options, has allowed the increased use of HCV positive organs in HCV positive and negative recipients. Machine perfusion, both cold and warm, has moved solidly into the liver transplant world potentiating optimization of marginal donors and also offering potential modulation of liver grafts (ie, gene therapy, stem cell therapy, and defatting). Finally, pharmacological and mechanical interventions in DCD procurement techniques have contributed to improved outcomes in DCD transplants. All of these are explored in this article as a tribute to innovative spirit of Dr. Starzl and his continued impact on liver transplant today.

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.

Repopulating the biliary tree from the peribiliary glands

The larger ducts of the biliary tree contain numerous tubulo-alveolar adnexal glands that are lined with biliary epithelial cells and connected to the bile duct lumen via small glandular canals. Although these peribiliary glands (PBG) were already described in the 19th century, their exact function and role in the pathophysiology and development of cholangiopathies have not become evident until recently. While secretion of serous and mucinous components into the bile was long considered as the main function of PBG, recent studies have identified PBG as an important source for biliary epithelial cell proliferation and renewal. Activation, dilatation, and proliferation of PBG (or the lack thereof) have been associated with various cholangiopathies. Moreover, PBG have been identified as niches of multipotent stem/progenitor cells with endodermal lineage traits. This has sparked research interest in the role of PBG in the pathogenesis of various cholangiopathies as well as bile duct malignancies. Deeper understanding of the regenerative capacity of the PBG may contribute to the development of novel regenerative therapeutics for previously untreatable hepatobiliary diseases. This article is part of a Special Issue entitled: Cholangiocytes in Health and Disease edited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.