Transplantation in paediatric patients with MMA requires multidisciplinary approach for achievement of good clinical outcomes.

BACKGROUND: As modern medicine is advancing, younger, small, and more complex children are becoming multi-organ transplant candidates. This brings up new challenges in all aspects of their care. METHODS: We describe the first report of a small child receiving a simultaneous liver and kidney transplant and abdominal rectus sheath fascia transplant on the background of Williams syndrome and methylmalonic acidaemia. At the time of transplantation, the child was 3 years old, weighed 14.0 kg, had chronic kidney disease stage V, and had not yet started any other form of kidney replacement therapy. RESULTS: There were many anaesthetic, medical, metabolic, and surgical challenges to consider in this case. A long general anaesthetic time increased the risk of cardiac complications and metabolic decompensation. Additionally, the small size of the patient and the organ size mis-match meant that primary abdominal closure was not possible. The patient's recovery was further complicated by sepsis, transient CNI toxicity, and de novo DSAs. CONCLUSIONS: Through a multidisciplinary approach between 9 specialties in 4 hospitals across England and Wales, and detailed pre-operative planning, a good outcome was achieved for this child. An hour by hour management protocol was drafted to facilitate transplant and included five domains: 1. management at the time of organ offer; 2. before the admission; 3. at admission and before theatre time; 4. intra-operative management; and 5. post-operative management in the first 24 h. Importantly, gaining a clear and in depth understanding of the metabolic state of the patient pre- and peri-operatively was crucial in avoiding metabolic decompensation. Furthermore, an abdominal rectus sheath fascia transplant was required to achieve abdominal closure, which to our knowledge, had never been done before for this indication. Using our experience of this complex case, as well as our experience in transplanting other children with MMA, and through a literature review, we propose a new perioperative management pathway for this complex cohort of transplant recipients.

Liver transplantation for HCC: validation of prognostic power of the RETREAT score for recurrence in a UK cohort.

BACKGROUND: The Risk Estimation of Tumor Recurrence After Transplant (RETREAT) score as a prognostic index for recurrence has been reported previously and has not been validated outside the USA. Our study has validated the score in a single center UK cohort of patients being transplanted for HCC. METHODS: LT for HCC between 2008 and 2018 at our center were analyzed. Recurrence-free survival (RFS) was compared by the RETREAT score and validated using Net Reclassification Improvement (NRI) by comparing it to Milan criteria. RESULTS: 346 adult HCC patients were transplanted of whom 313 were included. 28 (8.9%) had a recurrence. Summation of largest diameter and total number of viable tumors (HR = 1.19, p < 0.001), micro-/macro-vascular invasion (HR = 3.74, p = 0.002) and AFP>20 ng/ml (HR = 3.03, p = 0.005) were associated with recurrence on multivariate analysis. RFS decreased with increasing RETREAT score (log-rank p = 0.016). RETREAT performed better than Milan with significant NRI at 1- and 2-years post-transplant (0.43 (p = 0.004) and 0.38 (p = 0.03) respectively). CONCLUSION: LT outcomes using the revised UK criteria are equivalent to Milan criteria. Further, RETREAT score was validated as a prognostic index for the first time in a UK cohort and may assist risk stratification, selection for adjuvant therapies and guide surveillance.

Liver Transplantation for Biliary Atresia in Adulthood: Single-Centre Surgical Experience.

BACKGROUND: Biliary atresia (BA) is the most common indicator for liver transplant (LT) in children, however, approximately 22% will reach adulthood with their native liver, and of these, half will require transplantation later in life. The aim of this study was to analyse the surgical challenges and outcomes of patients with BA undergoing LT in adulthood. METHODS: Patients with BA requiring LT at the age of 16 or older in our unit between 1989 and 2020 were included. Pretransplant, perioperative variables and outcomes were analysed. Pretransplant imaging was reviewed to assess liver appearance, spontaneous visceral portosystemic shunting (SPSS), splenomegaly, splenic artery (SA) size, and aneurysms. RESULTS: Thirty-four patients who underwent LT for BA fulfilled the inclusion criteria, at a median age of 24 years. The main indicators for LT were synthetic failure and recurrent cholangitis. In total, 57.6% had significant enlargement of the SA, 21% had multiple SA aneurysm, and SPSS was present in 72.7% of the patients. Graft and patient survival at 1, 5, and 10 years was 97.1%, 91.2%, 91.2% and 100%, 94%, 94%, respectively Conclusions: Good outcomes after LT for BA in young patients can be achieved with careful donor selection and surgery to minimise the risk of complications. Identification of anatomical variants and shunting are helpful in guiding attitude at the time of transplant.

Outcomes of adults who received liver transplant as young children.

BACKGROUND: Patient and graft survival 20-years after pediatric liver transplantation (pLT) are excellent. In children, attainment of normal growth, education and social adaptation to be an independent adult are equally important. This is particularly relevant for children who receive liver transplant at a young age, where infantile-onset liver disease, surgery and immunosuppression can adversely affect growth and neurodevelopment. The aim of this study was to evaluate the long-term physical and psychosocial outcomes of pLT recipients with normal graft function. We coin the term 'meaningful survival'. METHODS: We performed a cross-sectional study of pLT recipients who received transplants between 1985 and 2004. A 20-year evaluation of physical health (growth, renal function), mental wellbeing and social outcomes (substance abuse, adherence, education, employment) was performed. All patients included were considered to have normal graft function. FINDINGS: Eighty-four patients met study criteria. Median age at transplantation was 1.3 years (IQR 0·7-3·3 years), with median duration of follow-up of 20.2 years (18·0-23·5). At median of 20-years, 19 patients (23%) had chronic renal dysfunction and 3 patients (4%) had a BMI of >30 (mean 20·4). Evaluation of long-term psychosocial outcomes demonstrated 22 patients (26%) with mental health disorders. Substance abuse was lower than national average. 62 patients (74%) were in education, employment or training. Overall, only 26% of our cohort achieved a composite outcome of 'meaningful survival'. INTERPRETATION: This is the largest reported long-term study of biopsychosocial outcomes of pLT recipients with normal liver biochemistry, with follow-up upon completion of physical growth and senior school education. Importantly, despite normal liver function, many patients did not demonstrate 'meaningful survival'. We must refocus our efforts towards better understanding the long-term outcomes of children. A 'meaningful survival' rather than mere survival should be our goal. FUNDING: None.

Improved survival in children with HPS: Experience from two high volume liver transplant centers across continents.

BACKGROUND: Severe HPS increases morbidity and mortality after LT in children. We reviewed the combined experience of LT for HPS in children from two LT centers in Europe and Asia. METHODS: All children with "proven" HPS as per ERS Task Force criteria (detailed in manuscript) who underwent LT were categorized into M (PaO2 ≥80 mmHg), Mo (PaO2  = 60-79 mmHg), S (50-59 mmHg), and VS (PaO2 <50 mmHg) HPS, based on room air PaO2 . RESULTS: Twenty-four children with HPS underwent 25 LT (one re-transplantation) at a median age of 8 years (IQR, 5-12), after a median duration of 8 (4-12) months following HPS diagnosis. Mechanical ventilation was required for a median of 3 (1.5-27) days after LT. Ten children had "S" post-operative hypoxemia, requiring iNO for a median of 5 (6-27) days. "VS" category patients had significantly prolonged invasive ventilation (median 35 vs. 3 and 1.5 days; p = .008), ICU stay (median 39 vs. 8 and 8 days; p = .007), and hospital stay (64 vs. 26.5 and 23 days; p < .001) when compared to "S" and "M/Mo" groups, respectively. The need for pre-transplant home oxygen therapy was the only factor predicting need for re-intubation. Patient and graft survival at 32 (17-98) months were 100% and 95.8%. All children ultimately had complete resolution of HPS. CONCLUSIONS: VS HPS is associated with longer duration of mechanical ventilation and hospital stay, which emphasizes the need for early LT in these children.

Diaphragmatic Hernia following Pediatric Liver Transplantation: An Underappreciated Complication Prone to Recur.

INTRODUCTION: Postoperative diaphragmatic hernia (DH) is a rare but potentially life-threatening complication following pediatric liver transplantation (LT). In the current literature, a total of 49 such hernias have been reported in 17 case series. We present eight additional cases, three of which reoccurred after surgical correction, and review the current literature with a focus on recurrence. MATERIALS AND METHODS: The study sample included children (<18 years of age) who underwent LT between June 2013 and June 2020 at five large transplant centers and who subsequently presented with DH. During the study period, a total of 907 LT was performed. Eight DH were recognized, and risk factors were analyzed. RESULTS: For the eight children with DH, the mean age at LT was 28.0 (5-132) months. All patients with a DH received left lateral segment split grafts except one, who received a full left lobe. The mean weight at time of LT was 11.8 (6.6-34) kg. Two patients had a primary abdominal muscle closure, and six had a temporary silastic mesh closure. All eight children presented with a right posterolateral DH. The small bowel was herniated in the majority of cases. Symptoms reported included nausea, vomiting, and respiratory distress. Two patients were asymptomatic, and discovery was incidental. All patients underwent prompt primary surgical repair. Three DH hernias (37.5%) recurred despite successful surgical correction. CONCLUSION: DH following liver transplant with technical variant grafts may be underreported and is prone to recur despite surgical correction. A better understanding of the pathophysiology and more thorough reporting may help increase awareness. Early detection and prompt surgical management are the cornerstones of a successful outcome.

A unique type of fully covered metal stent for the management of post liver transplant biliary anastomotic strictures.

BACKGROUND: We report our experience of treating anastomotic strictures using a novel type of fully covered metal stent (FCSEMS). This stent, known as the Kaffes Stent, is short-length with an antimigration waist and is easily removable due to long retrieval wires deployed within the duodenum. METHODS: Sixty-two patients underwent ERCP and Kaffes stent insertion for post-transplant anastomotic strictures following confirmation of a stricture on MRCP. These patients were retrospectively analysed for immediate and long-term stricture resolution, improvement in symptoms and liver function tests (LFTs), stricture recurrence and complication rates. RESULTS: Of the 56 patients who had their stent removed at the time of analysis, 54 (96%) had immediate stricture resolution and 42 continued to have long-term resolution (mean follow-up period was 548 days). Of the 16 patients with symptoms of biliary obstruction, 13 had resolution of their symptoms. Overall, there was a significant improvement in LFTs after stent removal compared to before stent insertion. Complication rates were 15% with only one patient requiring biliary reconstruction. CONCLUSIONS: The Kaffes stent is effective and safe at resolving post liver transplant biliary anastomotic strictures.

Deregulation of the Purine Pathway in Pre-Transplant Liver Biopsies Is Associated with Graft Function and Survival after Transplantation.

The current shortage of livers for transplantation has increased the use of marginal organs sourced from donation after circulatory death (DCD). However, these organs have a higher incidence of graft failure, and pre-transplant biomarkers which predict graft function and survival remain limited. Here, we aimed to find biomarkers of liver function before transplantation to allow better clinical evaluation. Matched pre- and post-transplant liver biopsies from DCD (n = 24) and donation after brain death (DBD, n = 70) were collected. Liver biopsies were analysed using mass spectroscopy molecular phenotyping. Discrimination analysis was used to parse metabolites differentiated between the two groups. Five metabolites in the purine pathway were investigated. Of these, the ratios of the levels of four metabolites to those of urate differed between DBD and DCD biopsies at the pre-transplantation stage (q < 0.05). The ratios of Adenosine monophosphate (AMP) and adenine levels to those of urate also differed in biopsies from recipients experiencing early graft function (EGF) (q < 0.05) compared to those of recipients experiencing early allograft dysfunction (EAD). Using random forest, a panel consisting of alanine aminotransferase (ALT) and the ratios of AMP, adenine, and hypoxanthine levels to urate levels predicted EGF with area under the curve (AUC) of 0.84 (95% CI (0.71, 0.97)). Survival analysis revealed that the metabolite classifier could stratify six-year survival outcomes (p = 0.0073). At the pre-transplantation stage, a panel composed of purine metabolites and ALT could improve the prediction of EGF and survival.

Occlusive Hepatic Artery Thrombus in a Deceased-Donor Liver Procured From a Donor With Blunt Abdominal Trauma Following a Road Traffic Collision Accident.

Here, we describe a case of occlusive hepatic artery thrombus in a liver procured from an 18-year-old deceased donor after circulatory death. The donor had died of multiple trauma following a road traffic collision. Occlusive thrombus was found at the hepatic artery bifurcation during back-table preparation. Consequently, the liver transplant did not proceed. We suggest careful assessment of hepatic arteries of all donor livers before transplant, particularly those from donors who are involved in deceleration injuries. Transplanting such livers may lead to primary nonfunction.

Liver Transplantation in Children With Propionic Acidemia: Medium-Term Outcomes.

Liver transplantation (LT) for patients with propionic acidemia (PA) is an emerging therapeutic option. We present a retrospective review of patients with PA who underwent LT at a tertiary liver center between 1995 and 2015. A total of 14 children were identified (8 males) with median age at initial presentation of 3 days (range, 0-77 days). Pretransplant median protein restriction was 1 g/kg/day (range, 0.63-1.75 g/kg/day), 71% required supportive feeding, and 86% had developmental delay. Frequent metabolic decompensations (MDs) were the main indication for LT with a median age at transplantation of 2.4 years (range, 0.8-7.1 years). Only 1 graft was from a living donor, and 13 were from deceased donors (4 auxiliary). The 2-year patient survival was 86%, and overall study and graft survival was 79% and 69%, respectively. Three patients died after LT: at 43 days (biliary peritonitis), 225 days (acute-on-chronic rejection with multiorgan failure), and 13.5 years (posttransplant lymphoproliferative disease). Plasma glycine and propionylcarnitine remained elevated but reduced after transplant. Of 11 survivors, 5 had at least 1 episode of acute cellular rejection, 2 sustained a metabolic stroke (with full recovery), and 3 developed mild cardiomyopathy after LT. All have liberalized protein intake, and 9 had no further MDs: median episodes before transplant, 4 (range, 1-30); and median episodes after transplant, 0 (range, 0-5). All survivors made some developmental progress after LT, and none worsened at a median follow-up of 5.8 years (range, 2-23 years). LT in PA significantly reduces the frequency of MDs, can liberalize protein intake and improve quality of life, and should continue to be considered in selected cases.

Outcomes of Liver Transplantation in Small Infants.

Liver transplantation (LT) for small infants remains challenging because of the demands related to graft selection, surgical technique, and perioperative management. The aim of this study was to evaluate the short-term and longterm outcomes of LT regarding vascular/biliary complications, renal function, growth, and patient/graft survival in infants ≤3 months compared with those of an age between >3 and 6 months at a single transplant center. A total of 64 infants ≤6 months underwent LT and were divided into 2 groups according to age at LT: those of age ≤3 months (range, 6-118 days; XS group, n = 37) and those of age >3 to ≤6 months (range, 124-179 days; S group, n = 27) between 1989 and 2014. Acute liver failure was the main indication for LT in the XS group (n = 31, 84%) versus S (n = 7, 26%). The overall incidence of hepatic artery thrombosis and portal vein thrombosis/stricture were 5.4% and 10.8% in the XS group and 7.4% and 11.1% in the S group, respectively (not significant). The overall incidence of biliary stricture and leakage were 5.4% and 2.7% in the XS group and 3.7% and 3.7% in the S group, respectively (not significant). There was no significant difference between the 2 groups in terms of renal function. No significant difference was found between the 2 groups for each year after LT in terms of height and weight z score. The 1-, 5-, and 10-year patient survival rates were 70.3%, 70.3%, and 70.3% in the XS group compared with 92.6%, 88.9%, and 88.9% in the S group, respectively (not significant). In conclusion, LT for smaller infants has acceptable outcomes despite the challenges of surgical technique, including vascular reconstruction and graft preparation, and perioperative management.

The difficult abdominal closure after paediatric intestinal transplantation: Use of abdominal rectus muscle fascia and literature review.

Primary abdominal wall closure after intestinal and multivisceral transplantation may not be possible because of loss of abdominal domain and/or graft size/abdominal cavity mismatch. Traditional closure techniques for the open abdomen may not be valid in these circumstances because of severe scarring of the abdominal wall from multiple previous surgeries in this particular group of patients. We present our initial experience with the use of non-vascularized abdominal rectus muscle fascia in two patients who underwent deceased donation and living-related combined liver and small bowel transplantation, respectively, and who could not be closed primarily. The donor fascia was attached to the recipient fascia in both patients. In either case, there was not enough skin cover for closure, the wound was left open, and a negative pressure dressing was applied. In both cases, over a period of 6 months after placement of the non-vascularized abdominal rectus muscle fascia, the wound contracted, granulation tissue gradually covered the wound, and healing occurred, giving an intact abdominal wall. The abdominal rectus muscle fascia from a deceased donor can be used in a definite procedure for closure of the abdominal wall either at the time of transplant or later when a suitable rectus muscle fascia graft becomes available.

Liver transplantation for neonatal-onset citrullinemia.

Citrullinemia or ASS deficiency in its classical form presents in the neonatal period with poor feeding, hyperammonemia, encephalopathy, seizures, and if untreated can be fatal. Despite advances in medical therapy, neurocognitive outcomes remain suboptimal. LT has emerged as a potential management option. A retrospective single-center review identified 7 children with a median age of 1.1 years (range, 0.6-5.8) at referral. Five children presented clinically, and 2 were treated prospectively from birth due to positive family history. All patients received standard medical and dietary therapy prior to LT. The indications for LT were frequent metabolic decompensations in 4, elective in 2, and ALF in 1. The median age at LT was 2.4 years (range, 1.3-6.5). Five patients received 6 left lateral segment grafts, one a live unrelated donor left lateral segment as an APOLT graft, and one a cadaveric whole liver graft as APOLT. One child required retransplantation due to hepatic artery thrombosis. Graft and patient survival were 86% and 100%, respectively. Median follow-up is 3.1 years (range, 0.1-4.1), and the median age at follow-up is 5.5 years (range, 4.0-9.8). There have been no metabolic decompensations in 6 children, while 1 patient (with APOLT) developed asymptomatic hyperammonemia with no clinical or histological signs of liver injury, requiring additional medical therapy. Our medium-term experience following LT in citrullinemia is favorable, demonstrating a positive transformation of the clinical phenotype.

An in silico argument for mitochondrial microRNA as a determinant of primary non function in liver transplantation.

Mitochondria have their own genomic, transcriptomic and proteomic machinery but are unable to be autonomous, needing both nuclear and mitochondrial genomes. The aim of this work was to use computational biology to explore the involvement of Mitochondrial microRNAs (MitomiRs) and their interactions with the mitochondrial proteome in a clinical model of primary non function (PNF) of the donor after cardiac death (DCD) liver. Archival array data on the differential expression of miRNA in DCD PNF was re-analyzed using a number of publically available computational algorithms. 10 MitomiRs were identified of importance in DCD PNF, 7 with predicted interaction of their seed sequence with the mitochondrial transcriptome that included both coding, and non coding areas of the hypervariability region 1 (HVR1) and control region. Considering miRNA regulation of the nuclear encoded mitochondrial proteome, 7 hypothetical small proteins were identified with homolog function that ranged from co-factor for formation of ATP Synthase, REDOX balance and an importin/exportin protein. In silico, unconventional seed interactions, both non canonical and alternative seed sites, appear to be of greater importance in MitomiR regulation of the mitochondrial genome. Additionally, a number of novel small proteins of relevance in transplantation have been identified which need further characterization.

Massive ascites and the heterozygous alpha 1 antitrypsin (α1 AT) living related donor liver in the homozygous child.

The following is a short report on the use of a heterozygous (PiMZ) alpha 1 antitrypsin (α1AT) living related donor liver in a homozygous (PiZ) child that was complicated by massive ascites early after transplant. This clinical report is then followed by a brief summary of present knowledge on the α1 AT protein and management of massive ascites in the pediatric liver transplant recipient.

The Effect of Recipient Body Mass Index and Its Extremes on Survival and Graft Vascular and Biliary Complications After Liver Transplantation: A Single Center Retrospective Study.

BACKGROUND This is the largest UK-based study on the effect of recipient body mass index (BMI) and its extremes (BMI <18.5 and BMI ≥35 kg/m²) on liver transplant (LT) outcomes. Its purpose was to analyze the BMI effect on post-LT mortality, graft loss, primary non-function (PNF), and graft vascular and biliary complications. MATERIAL AND METHODS Data were retrieved from a single-center LT database of 2,115 consecutive patients receiving first LT during period February 2004 to September 2015. Survivals were compared across the BMI groups; the effects of recipient BMI on survival, PNF, and graft vascular and biliary complications were analyzed via regression. RESULTS Autoimmune disease and nonalcoholic steatohepatitis were prevalent among underweight and morbidly obese adults, respectively. Graft survival was similar across BMI classes at 30 days and in 1, 2, 5, and 10 years (p=0.75) and on obese versus non-obese (p=0.33). BMI <35 kg/m² versus BMI ≥35 kg/m² mean graft survival was similar (p=0.84). BMI <18.5 kg/m² recipients tended to have inferior mean graft and patient survivals; however, the difference was non-significant (p=0.09 and p=0.1 respectively). BMI <18.5 kg/m² recipients were at higher risk of hepatic artery thrombosis (HR, 1.73, 95% CI 1.73-3, p<0.05). Adult underweight status was an independent HAT risk factor (HR 3, 95% CI 1-8.6, p=0.046). BMI class did not affect ischemic cholangiopathy risk (p=0.84). However, the overall biliary complication risk increased by 3% for every 1 kg/m² BMI rise. CONCLUSIONS Post-LT survival is independent of recipient BMI. Underweight status is linked to higher HAT risk. Biliary complication risk increases with rising recipient BMI. After appropriate recipient selection, recipient BMI extremes are not a contraindication for LT.

Developing a donation after cardiac death risk index for adult and pediatric liver transplantation.

AIM: To identify objective predictive factors for donor after cardiac death (DCD) graft loss and using those factors, develop a donor recipient stratification risk predictive model that could be used to calculate a DCD risk index (DCD-RI) to help in prospective decision making on organ use. METHODS: The model included objective data from a single institute DCD database (2005-2013, n = 261). Univariate survival analysis was followed by adjusted Cox-regressional hazard model. Covariates selected via univariate regression were added to the model via forward selection, significance level P = 0.3. The warm ischemic threshold was clinically set at 30 min. Points were given to each predictor in proportion to their hazard ratio. Using this model, the DCD-RI was calculated. The cohort was stratified to predict graft loss risk and respective graft survival calculated. RESULTS: DCD graft survival predictors were primary indication for transplant (P = 0.066), retransplantation (P = 0.176), MELD > 25 (P = 0.05), cold ischemia > 10 h (P = 0.292) and donor hepatectomy time > 60 min (P = 0.028). According to the calculated DCD-RI score three risk classes could be defined of low (DCD-RI < 1), standard (DCD-RI 2-4) and high risk (DCD-RI > 5) with a 5 years graft survival of 86%, 78% and 34%, respectively. CONCLUSION: The DCD-RI score independently predicted graft loss (P < 0.001) and the DCD-RI class predicted graft survival (P < 0.001).