Waitlist mortality in pediatric liver transplantation: The goal is zero

In this issue, Esmati et al.¹ present a fascinating analysis of the impact on waitlist outcomes of a 2014 Eurotransplant (ET) policy that prioritizes patients younger than the age of 2 years with biliary atresia for deceased donor liver transplantation (DDLT) offers. In comparing 882 children listed in the preimplementation phase with 173 children in the postimplementation phase, the authors found that waitlist mortality decreased from 6.7% before to 2.3% after implementation of the new policy. Unexpectedly, this was not associated with an increase in DDLTs. In addition, wait times for DDLT for these youngest children actually increased in the postpolicy versus prepolicy time period.

During the same time period, the proportion of young patients with BA who underwent living donor liver transplantation (LDLT) increased from 55% to 74%. The authors thus argue that the significant decline in waitlist mortality was attributed to the increase in LDLT. Although the postpolicy cohort is smaller and bigger sample sizes will be needed to confirm this trend, these findings are striking. The impact of LDLT both in terms of waitlist outcomes and longer term benefit is clear in the current data from Europe, the United States, and other countries.² LDLT needs to be implemented more widely. Why this increase in LDLT occurred in the ET experience will take further study.

This study highlights four important lessons in the liver transplantation community's approach to serving one of our most at‐risk populations who have continued to have the highest risk of death while on the waiting list in the United States and Europe: children aged younger than 2 years. ET focused on children specifically with biliary atresia, but these lessons apply to all children who require liver transplantation in very early childhood—and who deserve prioritization with the babies who have biliary atresia. First, Europe and other regions have set an example for the global community by intentional efforts to prioritize children for live‐saving liver grafts for DDLTs.^3,4 Their data‐driven policy is clearly further supported by the ethical justification for prioritizing children for this scarce resource.⁵ Their experience highlights that prioritizing children for DDLT does not de facto trigger decreased use of LDLT, which has been noted by some as an argument against increasing pediatric priority for adult deceased donors.

The second lesson is that there are clearly many potential ways to achieve our desired goal of zero waitlist mortality; multiple strategies can successfully be pursued in parallel. The authors hypothesize that raising awareness of children's waitlist mortality also spurred action to increase LDLT use. Reports from other countries outline complementary strategies that can also improve outcomes for children without disadvantaging adult candidates. For example, the United Kingdom's intent‐to‐split policy resulted in an even more dramatic reduction of waitlist mortality and was accomplished with DDLT technical variant split grafts.⁶ The UK policy addressed the goal of increasing pediatric access specifically by mandating that livers fitting specific criteria were allocated to two recipients as split‐liver transplants. Policy change focusing only on pediatric allocation may not have the desired effect—especially because young children depend on technical variant grafts, both in DDLT and LLDT, to have the best chance of a timely transplant. Despite the lack of impact on DDLT in the current study, the authors did not report on whether the proportion of split DDLT grafts increased after implementation of the modified score. Of note, the splitting of suitable livers in ET is not mandatory.

Third, we strongly concur with the authors' call to systematically evaluate the effects of policy after adjustment of allocation rules, although we note that this is done more routinely in some transplant systems than others. The US transplant community does regularly assess the impact of policy change, although these reassessments may take too much time and often do not distinguish between pediatric and adult outcomes, limiting their ability to drive efficient cycles of continuous improvement. Critically, projected outcomes based on even the best modeling practices^7,8 may not be found true in actual practice both because of an inability to predict behavior change (i.e., splitting more livers or implementing a living donor program) and because modeling for rare disease conditions such as in the smaller volume of our pediatric candidates remains challenging.

Fourth, the elephant in the room in many of these policy discussions is that without adaptions to the pediatric Model for End‐Stage Liver Disease (MELD) or Pediatric End‐Stage Liver Disease scores, children can never fairly “compete” for deceased donor livers because of the tremendous volume and demand from the adult candidate list. In the ET policy described here, the pediatric MELD score of 32 given to these children was thought to be a meaningful prioritization. However, unless coupled with other policy initiatives to incentivize or mandate splitting, it may not drive practice change.

In summary, pediatric liver transplantation waitlist mortality is a solvable problem, with the solution likely reachable by multiple paths that should be used in parallel toward the goal. Children cannot wait any longer. Alerting the transplant community to the fact that children still die on the liver transplantation waiting list is not new; that waitlist deaths continue to occur among children is especially tragic.⁹ Today, we are reminded that focused allocation policy to prioritize children is rational, ethical, and urgent. Multiple techniques—especially LDLT and splitting deceased donor livers—can be combined with policy change to eliminate preventable deaths; we just need to finally get it done.