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The demand for kidney transplant is quite high compared with the current supply, even with the increasing numbers of transplant deceased donors since 2019.6 Pediatric kidney-alone and multiple organ transplant candidates compete for the same high-quality donor kidneys, but under the current OPTN allocation policy multiple organ transplants have ultimate priority. During the study period, children receiving kidney-alone transplants had the highest one-year graft survival (98.2%) compared with K-P (96.6%) and other multiple organ transplants (87.9%-88.2%). Although the OPTN/UNOS has a well-defined history of giving priority to children, it has not yet begun to address in policy the multiple organ transplant effect on pediatric priority due to the perceived complexity of multiple organ allocation. [Extracted from the article]

Chronic hepatitis C viral infection represents a worldwide viral epidemic. The natural course of hepatitis C virus is less understood in the pediatric population, although fewer children progress to cirrhosis and end-stage liver disease than adults infected. In the last five years, epidemiological and clinical research involving hepatitis C virus-infected children has raised interesting observations regarding the differences in transmission, natural history, and response to treatment in this population. [ABSTRACT FROM AUTHOR]

Background: We examined the combined effects of donor age and graft type on pediatric liver transplantation outcomes with an aim to offer insights into the strategic utilization of these donor and graft options. Methods: A retrospective analysis was conducted using a national database on 0–2‐year‐old (N = 2714) and 3–17‐year‐old (N = 2263) pediatric recipients. These recipients were categorized based on donor age (≥40 vs <40 years) and graft type. Survival outcomes were analyzed using the Kaplan–Meier and Cox proportional hazards models, followed by an intention‐to‐treat (ITT) analysis to examine overall patient survival. Results: Living and younger donors generally resulted in better outcomes compared to deceased and older donors, respectively. This difference was more significant among younger recipients (0–2 years compared to 3–17 years). Despite this finding, ITT survival analysis showed that donor age and graft type did not impact survival with the exception of 0–2‐year‐old recipients who had an improved survival with a younger living donor graft. Conclusions: Timely transplantation has the largest impact on survival in pediatric recipients. Improving waitlist mortality requires uniform surgical expertise at many transplant centers to provide technical variant graft (TVG) options and shed the conservative mindset of seeking only the "best" graft for pediatric recipients. [ABSTRACT FROM AUTHOR]

Machine learning analyses allow for the consideration of numerous variables in order to accommodate complex relationships that would not otherwise be apparent in traditional statistical methods to better classify patient risk. The SPLIT registry data were analyzed to determine whether baseline demographic factors and clinical/biochemical factors in the first‐year post–transplant could predict ideal outcome at 3 years (IO‐3) after LT. Participants who received their first, isolated LT between 2002 and 2006 and had follow‐up data 3 years post–LT were included. IO‐3 was defined as alive at 3 years, normal ALT (<50) or GGT (<50), normal GFR, no non‐liver transplants, no cytopenias, and no PTLD. Heat map analysis and RFA were used to characterize the impact of baseline and 1‐year factors on IO‐3. 887/1482 SPLIT participants met inclusion criteria; 334 had IO‐3. Demographic, biochemical, and clinical variables did not elucidate a visual signal on heat map analysis. RFA identified non‐white race (vs white race), increased length of operation, vascular and biliary complications within 30 days, and duct‐to‐duct biliary anastomosis to be negatively associated with IO‐3. UNOS regions 2 and 5 were also identified as important factors. RFA had an accuracy rate of 0.71 (95% CI: 0.68‐0.74), PPV = 0.83, and NPV = 0.70. RFA identified participant variables that predicted IO‐3. These findings may allow for better risk stratification and personalization of care following pediatric liver transplantation. [ABSTRACT FROM AUTHOR]

Background: The number of programs offering a PTH fellowship has grown rapidly over the last 10 years. This study aimed to describe the clinical, didactic, procedural, and research experiences of recent PTH fellowship graduates. In addition, we sought to understand graduates' post‐fellowship professional responsibilities and their perception about the utility of the PTH fellowship. Methods: An anonymous survey was distributed from February to October 2020 through REDCap to all recent graduates (2015–2019) of an ACGME‐approved PTH fellowship program. The survey consisted of 49 questions focused on the PTH fellowship experience. Results were summarized using descriptive statistics. Results: Thirty‐eight of 43 graduates (88%) responded to the survey representing 12 PTH fellowship programs. The didactic experience varied; 97% received pathology lectures, 81% radiology lectures, 54% organ allocation lectures, 54% procedural lectures, 57% immunology lectures, and 43% live donation lectures. During the PTH fellowship, the majority of fellows performed >10 liver biopsies (82%) and >5 variceal bandings (58%); however, 63%, 32%, 8%, and 8% never performed paracentesis, variceal sclerotherapy, variceal banding, and liver biopsies, respectively. The majority of fellows (95%) completed a research project during PTH fellowship. Currently, 84% of graduates are employed at a transplant academic institution. All graduates recommended the fellowship. Conclusions: There is variability in the didactic, clinical, and procedural training among PTH fellowship programs. Although uniformly viewed as a beneficial fellowship year, there is an opportunity to collaborate to create a more standardized training experience. [ABSTRACT FROM AUTHOR]

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]

SARS-CoV-2 infection during the Omicron period was frequent amongst a cohort of vaccinated pediatric solid organ transplant recipients (pSOTRs) despite robust anti-receptor-binding domain (anti-RBD) antibody response, suggesting poor neutralizing capacity against Omicron subvariants. Breakthrough infections among pSOTRs were overall limited in severity. [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]

Background: Retrospective studies have demonstrated the efficacy and safety of pediatric and adolescent transjugular intrahepatic portosystemic shunt (TIPS), but long-term outcomes warrant further investigation. Objective: To report on the development of hyperplastic hepatic nodular lesion development in children and young adults (<21 years) with TIPS patency >3 years. Materials and methods: Eighteen children and young adults, including 10 (55.6%) females and 8 (44.4%) males, underwent TIPS creation with >3 years' patency and follow-up evaluation at a tertiary children's hospital. The mean age at the time of TIPS creation was 12.5±5.1 years (range: 1.5–20.0 years). The mean model for end-stage liver disease (MELD) at the time of TIPS creation was 8.1±1.6 (range: 6–11). Indications for TIPS creation included acute variceal bleeding (8/18, 44.4%), primary (1/18, 5.6%) or secondary (7/18, 38.9%) prevention of varices, portal vein thrombosis (1/18, 5.6%), and splenic sequestration (1/18, 5.6%). Technical successes, intra-procedural parameters, hemodynamic and clinical successes, TIPS patencies, adverse events, imaging evaluations, and follow-ups were recorded. Results: All (100%) TIPS placements were successful; however, a direct intrahepatic portosystemic shunt was created in one (5.6%) patient. Mean reduction of the portosystemic shunt gradient was 9.1±3.3 mmHg (range: 4–16 mmHg). Seventeen (94.4%) patients demonstrated clinical success with resolution of their initial clinical indication for TIPS placement. The 3-year TIPS primary, primary-assisted, and secondary patencies were 83.3% (15/18), 94.4% (17/18), and 100% (18/18), respectively. Two (11.1%) patients developed mild, medically controlled hepatic encephalopathy. One (5.6%) patient developed hepatopulmonary syndrome. Nine (50%) patients developed single or multiple hepatic nodules at a mean imaging surveillance time after TIPS of 4.4±3.0 years (range: 1.5–10.2 years). Six (33.3%) patients developed nodules >1 cm with imaging features most consistent with focal nodular hyperplasia or focal nodular hyperplasia-like nodules. The mean follow-up duration was 5.7±2.9 years (range: 3.0–13.1 years). Conclusion: Long-term (>3 years) portosystemic shunting via TIPS is associated with the development of hepatic nodular lesions in children. Consequently, children with TIPS may need gray-scale assessment of hepatic parenchyma as part of routine ultrasound exams and extended imaging surveillance until more is understood regarding the natural history of induced nodularity. [ABSTRACT FROM AUTHOR]

Background: Accurate and reproducible means of measuring the portosystemic gradient are essential for risk stratification and treatment of portal hypertension. Objective: To report the reliability of hepatic venous pressure gradients in children with intrahepatic veno-venous collateralization. Materials and methods: Between January 2012 and December 2019 (96 months), 39 patients with native livers underwent wedge hepatic venography and hepatic venous pressure gradient measurements at a tertiary pediatric center. All archived images were reviewed for balloon isolation of the hepatic vein and hepatic vein-to-hepatic vein (HV-HV) collaterals. HV-HV collaterals were categorized as present on the basis of non-catheterized segmental venous opacification despite appropriate balloon isolation. Hepatic venous pressure gradient was defined as the difference of wedge and free hepatic venous pressures. Wedge portosystemic gradient was defined as the difference between wedge hepatic venous pressure and right atrial (RA) pressures. For patients subsequently undergoing portal venous catheterization, portosystemic gradient was defined as the difference between main portal vein and RA pressures. Results: Thirteen of 39 (33.3%) patients demonstrated HV-HV collaterals on wedge hepatic venography. The mean hepatic venous pressure gradient was 5.2±3.8 mmHg (range: 0–15 mmHg). The mean hepatic venous pressure gradient was 3.6±2.6 mmHg (range: 0–9 mmHg) in the presence of HV-HV collaterals and 5.9±4.2 mmHg (range: 1–15 mmHg) in the absence of HV-HV collaterals (P=0.043). Twelve (30.8%) patients were found to have varices: 10 gastroesophageal, 1 rectal and 1 stomal. The mean hepatic venous pressure gradient in patients with varices was 5.4±47 mmHg (range: 0–15 mmHg). For patients with varices, mean hepatic venous pressure gradient was 3.0±2.7 mmHg (range: 0–9 mmHg) in the presence of HV-HV collaterals and 10.3±4.1 mmHg (range: 5–15 mmHg) in the absence of HV-HV collaterals (P=0.004). Four (10.3%) patients had extrahepatic portal vein occlusion: 3 with cavernous transformation and 1 with type Ib Abernethy malformation. All patients with extrahepatic portal vein occlusion demonstrated HV-HV collaterals compared with 8 of 35 (22.9%) patients without extrahepatic portal vein occlusion (P=0.002). Four of 39 (10.3%) patients underwent direct portal pressure measurements: 3 via transhepatic and 1 via trans-splenic portal access. All had demonstrated HV-HV collaterals on wedged imaging. One had extrahepatic portal vein occlusion. The mean time between wedge portosystemic gradient and portosystemic gradient measurement was 3.75 days (range: 0–8 days). The mean wedge portosystemic gradient was 4.5±3.1 mmHg (range: 2–9 mmHg) and the mean portosystemic gradient was 14.5±3.7 mmHg (range: 12–20 mmHg) (P=0.006). Conclusion: HV-HV collateralization is frequently observed in children undergoing wedged portal venography and leads to misrepresentative hepatic venous pressure gradients. All patients undergoing hepatic venous pressure gradient measurement should have wedged venography to identify HV-HV collaterals and to qualify measured pressures. Additional techniques to obtain representative pressures in the presence of HV-HV collaterals warrant further investigation. [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]