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Background: Adolescent solid organ transplant recipients (aSOTRs) who received three doses of the COVID‐19 mRNA vaccine experience high seroconversion rates and antibody persistence for up to 3 months. Long‐term antibody durability beyond this timeframe following three doses of the SARS‐CoV‐2 mRNA vaccine remains unknown. We describe antibody responses 6 months following the third vaccine dose (D3) of the BNT162b2 mRNA vaccination among aSOTRs. Methods: Participants in a multi‐center, observational cohort who received the third dose of the vaccine were analyzed for antibodies to the SARS‐CoV‐2 spike protein receptor‐binding domain (Roche Elecsys anti‐SARS‐CoV‐2‐S positive: ≥0.8, maximum: >2500 U/mL). Samples were collected at 1‐, 3‐, and 6‐months post‐D3. Participants were surveyed at each timepoint and at 12‐months post‐D3. Results: All 34 participants had positive anti‐RBD antibody titers 6 months post‐D3. Variations in titers occurred between 3 and 6 months post‐D3, with 8/28 (29%) having decreased antibody levels at 6 months compared to 3 months and 2/28 (7%) reporting increased titers at 6 months. The remaining 18/28 (64%) had unchanged antibody titers compared to 3‐month post‐D3 levels. A total of 4/34 (12%) reported breakthrough infection within 6 months and 3/32 (9%) reported infection after 6–12 months following the third dose of the SARS‐CoV‐2 mRNA vaccine. Conclusions: The results suggest that antibody durability persists up to 6 months following three doses of the SARS‐CoV‐2 mRNA in aSOTRs. Demography and transplant characteristics did not differ for those who experienced antibody weaning. Breakthrough infections did occur, reflecting immune‐evasive nature of novel variants such as Omicron. [ABSTRACT FROM AUTHOR]

Background: There has not been a comprehensive global survey of pediatric‐deceased donor allocation practices across all organs since the advent of deceased donor transplantation at the end of the 20th century. As an international community that is responsible for transplanting children, we set out to survey the existing landscape of allocation. We aimed to summarize current practices and provide a snapshot overview of deceased donor allocation practices to children across the world. Methods: The International Registry in Organ Donation and Transplantation (IRODAT, www.irodat.org) was utilized to generate a list of all countries in the world, divided by continent, that performed transplantation. We reviewed the published literature, published allocation policy, individual website references and associated links to publicly available listed allocation policies. Following this, we utilized tools of communication, relationships, and international fellowship to confirm deceased donation pediatric centers and survey pediatric allocation practices for liver, kidney, heart, and lung across the world. We summarize pediatric allocation practices by organ when available using source documents, and personal communication when no source documents were available. Results: The majority of countries had either formal or informal policies directed toward minimizing organ distribution disparity among pediatric patients. Conclusion: Children have long‐term life to gain from organ donation yet continue to die while awaiting transplantation. We summarize global strategies that have been employed to provide meaningful and sustained benefit to children on the waitlist. [ABSTRACT FROM AUTHOR]

Adult liver transplant programs have heretofore been hesitant to perform liver retransplantation in adult patients who underwent primary liver transplantation as a child (P_A). Areas of concern include: (a) potential disruption in care when transferring from a pediatric to an adult transplant center; (b) generally inferior outcomes of retransplantation; (c) reputation of young adults for non‐adherence to post‐transplant regimen; and (d) potential higher work effort for equivalent outcomes. To examine these concerns, we reviewed data on all US liver adult retransplants from 10/01/1987 to 9/30/2017. We propensity matched the P_A patients to patients who received both primary and retransplantation as adults (A_A), with ≥550 days between transplants. A mixed Cox proportional hazards model with program size and time period of transplantation as random variables revealed that retransplantation of P_A patients produced no significantly different graft survival or patient survival rates than retransplantation of the matched A_A patients. Therefore, inferior rates of liver retransplantation in these patients and concerns about continuity of care in changing transplant programs are not as believed in the wider liver transplant community. In conclusion, liver transplant centers should be optimistic about retransplanting adults who received their primary transplants as children. [ABSTRACT FROM AUTHOR]

Introduction: Indications for TIPS are well described in adults and involve complications of PHTN. Complications from PHTN are associated with PSG of > 12 mm Hg in adults. It is unclear if these parameters apply to children with PHTN. Objective: To assess whether adult criteria for TIPS placement can be utilized in children, describe laboratory changes over time, and report outcomes. Methods: We performed a retrospective review of 34 pediatric patients who underwent TIPS, examining indications, radiology, PSG reductions, laboratory changes, and outcomes. Results: Most patients had PHTN due to parenchymal liver disease including congenital hepatic fibrosis (n = 5), biliary atresia (n = 5), cystic fibrosis–related liver disease (n = 3) and cavernous transformation of the portal vein (n = 6). Indications for TIPS included variceal bleeding, recurrent ascites, and maintenance of portal vein flow following thrombolysis. Variceal bleeding was observed in six children with PSG < 12 mm Hg. Minor complications occurred in eight subjects. Continued bleeding occurred in one patient. Six patients were successfully bridged to transplantation, and three patients died secondary to end‐stage disease. Standard laboratory tests stabilized after TIPS placement and hematocrit increased. Conclusion: TIPS placement in pediatric patients was performed for complications of PHTN. Unlike adult series, a substantial proportion of our cases treated extrahepatic PHTN from cavernous transformation of the portal vein. Children presented with sequelae of PHTN with PSG below 12 mm Hg, below the adult standard. We found TIPS in pediatrics to be safe and effective with laboratory stabilization and improvement in hematocrit. [ABSTRACT FROM AUTHOR]

Objective: To investigate Doppler US and catheter venogram correlates to improve detection of transplant HVOO and avoid unnecessary invasive imaging procedures. Materials and methods: A retrospective review was performed in all pediatric OLT patients undergoing catheter venography of the hepatic veins between 2007 and 2017 at a single large tertiary pediatric liver transplant institution. Results: Forty‐four transplant hepatic venograms in 32 OLT patients were included (mean 1.38, range 1‐4 venograms per patient). All venograms were preceded by an independent Doppler US examination. Twenty‐one (47.7%) venograms were performed for the investigation of suspected HVOO based on Doppler US alone, 19 (43.2%) were performed for TJLB without suspected HVOO, 4 (9.1%) were performed for both. Sixteen (36.3%) instances of >50% anastomotic stenosis were identified. Mean peak anastomotic velocities were 208 cm/s and 116 cm/s in the presence and absence of a >50% venographic stenosis, respectively (P < 0.004). In all cases where there was a monophasic waveform seen on Doppler US, there was a > 50% stenosis seen on hepatic vein venogram. In all cases where a triphasic waveform was seen on Doppler US, there was no stenosis seen on hepatic vein venogram. Conclusion: While a Doppler US velocity threshold providing both high sensitivity and specificity has yet to be identified, increasing peak anastomotic velocity and decreasing intrahepatic venous velocity correlate strongly with venographic outflow stenosis. The presence of a triphasic intrahepatic waveform provides good NPV. [ABSTRACT FROM AUTHOR]