Can we minimize wait‐list mortality in young children with Biliary atresia?

See Article on Page 810 Potential conflict of interest: Nothing to report. Biliary atresia (BA) remains a major indication for liver transplantation (LT) in children younger than 2 years of age.1 Despite the successful application of Kasai portoenterostomy in experienced pediatric centers today, approximately 40%‐70% of children still develop end‐stage liver disease and require LT within 2 years.2 With an excellent 10‐year graft survival rate of 71%‐90% after transplantation, early recognition of deterioration after failed Kasai and subsequent listing appears crucial to avoid prolonged waiting time and death before a graft becomes available.1 This is of particular importance in children without the option of living donor LT. Thus, identification of predictors for wait‐list mortality is crucial in this cohort. In this issue of Liver Transplantation, van der Doef et al. report on outcomes of 711 young children listed with BA in the Eurotransplant registry.5 In this cohort, the wait‐list mortality increased from 4.1% to 7.9% between 3 and 24 months after registration, whereas 86.9% of candidates received a liver graft within 2 years.5 The authors focused on predictors of wait‐list mortality in children listed before the age of 5 years. A higher Model for End‐Stage Liver Disease (MELD) score and the candidates' age at the time of listing were independent risk factors. All children who died while waiting were younger than 2 years at the time of listing with a significantly higher risk for those between 0 and 0.5 month of age who suffered from an advanced liver disease with a MELD score of more than 20 points. From this cohort, 21% did not survive a 6‐month waiting period.5 Although the risk factors for wait‐list mortality described here are not entirely new, this study is the first involving children from 5 countries in Europe. In contrast, a majority of previous reports included data from the United States or Japan1 and demonstrated a higher Pediatric End‐Stage Liver Disease (PELD) score as a predictor of wait‐list mortality.7 This is not surprising because age is already computed in the PELD score. Results from this European study, therefore, paralleled previous findings in other countries regarding the impact of disease severity.6 Additionally, the significantly higher risk of deterioration prior to engrafting in very young children has been described by many.1 Effective medical treatment to prevent variceal bleeding or cholangitis combined with aggressive nutritional support prior to LT is very important to maintain such candidates in a reasonable condition for transplantation.2 Accordingly, 1 important task is to further increase access to the scarce resource of a donor liver. Although recent series report an increasing number of up to 50% living donor LTs and 30%‐40% whole or split grafts from deceased donors,3 very young children are exposed to a prolonged waiting time. Furthermore, transplantation is related to several technical issues in this population. This is particularly apparent when no living donor becomes available in children with a body weight of <5 kg and a graft‐to‐body weight ratio of >4%. Such candidates are exposed to a high risk for large‐for‐size syndrome, which is related to a high morbidity with subsequent prolonged ventilation time and hospital stay.1 In this context, Kasahara et al. recently described a new technique to further reduce left lateral liver grafts for very small children in order to achieve primary abdominal closure to decrease the duration of ventilation and intensive care unit admission with subsequent prevention of severe infectious complications.1 Despite such technical efforts, many livers are not split because of the lack of a mandatory split policy in many regions. Although some European countries accept donor livers up to 50 years of age for a split with good results, this young cohort will certainly benefit from an expansion of split criteria.8 It is also noteworthy to mention that the implementation of new guidelines for transplant centers regarding the required caseload of splits and a potential “payback” of split grafts may incentivize adult transplant centers to split, increasing the overall numbers.8 Additionally, the debate is ongoing for how to further prioritize such young and very sick children and on which criteria to base the prioritization. In this context, the United Network for Organ Sharing allows for regional and case‐specific review of petitions for exception points on the basis of medical need in pediatric patients.6 For example, children with a calculated PELD score of >25, requiring renal replacement therapy, mechanical ventilation, or a high number of packed red blood cell transfusions (>30 mL/kg weight/24 hours) are prioritized as category IB, just a step below super‐urgent listing. The clinical implications of this study are significant because it is the first report of wait‐list mortality and risk factors in a large cohort of children with BA that involves 5 European countries. The review of such results is of utmost importance to understand where centers can further improve outcomes. Despite an overall growing number of transplantations, split procedures have not increased proportionally in recent years. Implementation of standardized protocols for listing, allocation, prioritization, and modifications of split policies will potentially decrease wait‐list mortality in this high‐risk cohort.