ABO-incompatible heart transplantation-evolution of a revolution.

In the 1990s, neonates born with severe congenital heart disease faced more than 50% mortality awaiting an ABO-compatible (ABOc) transplant donor. This desperate situation, together with knowledge of gaps in the adaptive immune system in early childhood, led to the clinical exploration of intentional ABO-incompatible (ABOi) heart transplantation. In 2001, West et al. reported the first series of 10 infants in Canada. Since then, consideration of ABOi heart donors has become the standard of care for children awaiting transplantation in the first few years of life, resulting in reduced wait times and better organ utilization with noninferior post-transplant outcomes compared to ABOc recipients. This state-of-the-art review discusses the clinical development and evolution, underlying and resulting immunological aspects, current challenges, and future directions of ABOi heart transplantation.

Let's get physical: Aerobic capacity, muscle strength, and muscle endurance after pediatric heart transplantation.

BACKGROUND: Pediatric heart (HTx) and kidney transplant (KTx) recipients may have lower physical fitness than healthy children. This study sought to quantify fitness levels in transplant recipients, investigate associations to clinical factors and quality of life, and identify whether a quick, simple wall-sit test is feasible as a surrogate for overall fitness for longitudinal assessment. METHODS: Aerobic capacity (6-min walk test, 6MWT), normalized muscle strength, muscle endurance, physical activity questionnaire (PAQ), and quality of life (PedsQL™) were prospectively assessed in transplanted children and matched healthy controls. RESULTS: Twenty-two HTx were compared to 20 controls and 6 KTx. 6MWT %predicted was shorter in HTx (87.2 [69.9-118.6] %) than controls (99.9 [80.4-120] %), but similar to KTx (90.3 [78.6-115] %). Muscle strength was lower in HTx deltoids (6.15 [4.35-11.3] kg/m2) and KTx quadriceps (9.27 [8.65-19.1] kg/m2) versus controls. Similarly, muscle endurance was lower in HTx push-ups (28.6 [0-250] %predicted), KTx push-ups (8.35 [0-150] %predicted), HTx curl-ups (115 [0-450] %predicted), and KTx wall-sit time (18.5 [10.0-54.0] s) than controls. In contrast to HTx with only 9%, all KTx were receiving steroid therapy. The wall-sit test significantly correlated with other fitness parameters (normalized quadriceps strength R = .31, #push-ups R = .39, and #curl-ups R = .43) and PedsQL™ (R = .36). CONCLUSIONS: Compared to controls, pediatric HTx and KTx have similarly lower aerobic capacity, but different deficits in muscle strength, likely related to steroid therapy in KTx. The convenient wall-sit test correlates with fitness and reported quality of life, and thus could be a useful easy routine for longitudinal assessment.

Review on clinician bias and its impact on racial and socioeconomic disparities in pediatric heart transplantation.

This expert review seeks to highlight implicit bias in health care, transplant medicine, and pediatric heart transplantation to focus attention on the role these biases may play in the racial/ethnic and socioeconomic disparities noted in pediatric heart transplantation. This review breaks down the transplant decision making process to highlight points at which implicit bias may affect outcomes and discuss how the science of human decision making may help understand these complex processes.

Paediatric heart transplantation: life-saving but not yet a cure.

In the 1980s, heart transplantation was the first successful treatment for infants born with hypoplastic left heart syndrome. Infants who have required heart transplantation benefit from immunologic "advantages," including long-term survival free from cardiac allograft vasculopathy. Currently ∼ 90% of children undergoing a heart transplant are reaching their first-year anniversary and the clinical practices of paediatric heart transplantation have dramatically improved. These successes are largely attributed to research sponsored by the Pediatric Heart Transplant Study Group, the International Society of Heart and Lung Transplantation and, more recently, the Non-profits Enduring Hearts and Additional Ventures. Despite these successes, the field is challenged to increase progress to achieve long-term survival into adulthood. The wait-list mortality, especially among infants, is unacceptably high often leading to palliative measures that can increase post-transplant mortality. Cardiac allograft vasculopathy remains a major cause for progressive graft loss of function and sudden death. The relative tolerance seen in immature recipients has not been translated to modifying older recipients' post-transplant outcomes. The modifiable cause(s) for the increased risks of transplantation in children of different ethnicities and races require definition. Addressing these challenges faces the reality that for-profit research favours funding adult recipients, with ∼ 10-fold greater numbers, and their more modest longevity goals. Advocacy for funding "incentives" such as the Orphan Drug rules in the United States and upholding principles of equity and inclusion are critical to addressing the challenges of paediatric heart transplant recipients worldwide.

Impact of the Pediatric ABO Policy Change on Listings, Transplants, and Outcomes for Children Younger Than 2 Years Listed for Heart Transplantation in the United States.

BACKGROUND: We assessed the impact of the liberalized ABO pediatric policy change on candidate characteristics and outcomes for children undergoing heart transplant (HT). METHODS AND RESULTS: Children <2 years undergoing HT with ABO strategy reported at listing and HT from December 2011 to November 2020 to the Scientific Registry of Transplant Recipients database were included. Characteristics at listing, HT, and outcomes during the waitlist and post-transplant were compared before the policy change (December 16, 2011 to July 6, 2016), and after the policy change (July 7, 2016 to November 30, 2020). The percentage of ABO-incompatible (ABOi) listings did not increase immediately after the policy change (P = .93); however, ABOi transplants increased by 18% (P < .0001). At listing, both before and after the policy change, ABOi candidates had higher urgency status, renal dysfunction, lower albumin, and required more cardiac support (intravenous inotropes, mechanical ventilation) than those listed ABO compatible (ABOc). On multivariable analysis, there were no differences in waitlist mortality between children listed as ABOi and ABOc before the policy change (adjusted hazard ratio [aHR] 0.80, 95% confidence interval [CI] 0.61-1.05, P = .10) or after the policy change (aHR 1.2, 95% CI 0.85-1.6, P = .33). Post-transplant graft survival was worse for ABOi transplanted children before the policy change (aHR 1.8, 95% CI 1.1-2.8, P = .014), but not significantly different after the policy change (aHR 0.94, 95% CI 0.61-1.4, P = .76). After the policy change, ABOi listed children had significantly shorter waitlist times (P < .05). CONCLUSIONS: The recent pediatric ABO policy change has significantly increased the percentage of ABOi transplantations and decreased waitlist times for children listed ABOi. This change in policy has resulted in broader applicability and actual performance of ABOi transplantation with equal access to ABOi or ABOc organs, and thus eliminated the potential disadvantage of only secondary allocation to ABOi recipients.

Organ Donation in Canadian PICUs: A Cross-Sectional Survey, 2021-2022.

OBJECTIVES: To understand contemporary pediatric organ donation programs in Canadian PICUs, including: policies and practices, data collection and reporting, and system and process barriers. DESIGN: A cross-sectional survey carried out 2021-2022. SETTING: Canadian PICUs affiliated with a donor physician network. SUBJECTS: Pediatric intensivists identified as the donation program lead, or most knowledgeable about donation for their institution. MEASUREMENTS AND MAIN RESULTS: A 19-item survey was developed through collaboration with stakeholders from the organ donation and transplantation community within Canada. Domains and items were generated and reduced iteratively during an in-person workshop. Pretesting and pilot testing were completed to ensure readability, flow, clinical sensibility, and construct validity. Fifteen of 16 (94%) invited Canadian PICUs from seven provinces completed the survey representing 88% (15/18) of all noncardiac Canadian PICUs. Surveys were completed between June 2021 and September 2022. All units support donation after death by neurologic criteria (DNC); 14 of 15 indicated donation policies were in place and 1 of 15 indicated no policy but the ability to facilitate donation. Thirteen of 15 units (87%) support donation after death by circulatory criteria (DCC) with policies in place, with 11 of 13 of these indicating routine support of donation opportunities. The majority (13/15) of units identified a donation champion. Of the 16 identified champions across these centers, 13 were physicians and were registered nurses or nurse practitioners. Eight of 13 units (62%) with donation champions had positions supported financially, of which 5 units came from the Organ Donation Organization and the other 3 came from the provincial health authority. Finally, only 3 of 15 PICU donation programs have a pediatric donation committee with family involvement. Variability exists in identification (including determination of death practices), referral, and approach for donation between units. CONCLUSIONS: Although all Canadian PICUs support donation after DNC donation, and most support donation after DCC, variability exists in the identification, referral, and approach of potential donors. There is a notable lack of family involvement in pediatric donation programs. There are many opportunities for standardization of PICU donation programs which may result in improved rates of pediatric organ donation in Canada.

Evaluating a Telemedicine Video Game-Linked High-Intensity Interval Training Exercise Programme in Paediatric Heart Transplant Recipients.

Paediatric heart transplant recipients (HTRs) have reduced exercise capacity, physical activity (PA), health-related quality of life (HRQoL), and self-efficacy towards PA. Exercise interventions have demonstrated improvements in exercise capacity and functional status in adult HTRs, with a specific emerging interest in the role of high-intensity interval training (HIIT). Studies of exercise interventions in paediatric HTRs have been limited and nonrandomized to date. HIIT has not yet been evaluated in paediatric HTRs. We thus seek to evaluate the safety and feasibility of a randomized crossover trial of a 12-week, home-based, video game-linked HIIT intervention using a cycle ergometer with telemedicine and remote physiological monitoring capabilities (MedBIKE) in paediatric HTRs. The secondary objective is to evaluate the impact of the intervention on (1) exercise capacity, (2) PA, (3) HRQoL and self-efficacy towards PA, and (4) sustained changes in secondary outcomes at 6 and 12 months after intervention. After a baseline assessment of the secondary outcomes, participants will be randomized to receive the MedBIKE intervention (12 weeks, 36 sessions) or usual care. After the intervention and a repeated assessment, all participants will cross over. Follow-up assessments will be administered at 6 and 12 months after the MedBIKE intervention. We anticipate that the MedBIKE intervention will be feasible and safely yield sustained improvements in exercise capacity, PA, HRQoL, and self-efficacy towards PA in paediatric HTRs. This study will serve as the foundation for a larger, multicentre randomized crossover trial and will help inform exercise rehabilitation programmes for paediatric HTRs.

La tolérance à l'effort, le niveau d'activité physique (AP), le score de la qualité de vie liée à la santé (QVLS) ainsi que l'auto-efficacité à la pratique d'une AP se trouvent diminués chez les patients pédiatriques ayant reçu une transplantation cardiaque. Il a été montré que les exercices physiques permettent d'améliorer la tolérance à l'effort ainsi que le statut fonctionnel chez les patients adultes ayant reçu une transplantation cardiaque. D'ailleurs, le rôle de l'entraînement par intervalles de haute intensité (EIHI) suscite depuis peu un nouvel intérêt à cet égard. Les études réalisées à ce jour sur les programmes d'activité physique chez les patients pédiatriques ayant reçu une transplantation cardiaque sont toutefois peu nombreuses et ne reposent pas sur une répartition aléatoire. De plus, l'EIHI n'a pas encore été évalué chez ce groupe de patients. La présente étude a donc pour objectif d'évaluer la faisabilité et l'innocuité d'un essai clinique croisé à répartition aléatoire d'une durée de 12 semaines chez des patients pédiatriques ayant reçu une transplantation cardiaque. Le programme d'activité physique prendra la forme d'un EIHI à la maison au moyen d'un jeu vidéo et d'une bicyclette ergométrique permettant une assistance et une surveillance des données physiologiques à distance (MedBIKE). Les objectifs secondaires de l'étude consistent à évaluer les effets du programme sur : 1) la tolérance à l'effort; 2) le niveau d'AP; 3) la QVLS ainsi que l'auto-efficacité à la pratique d'une AP; et 4) le maintien des améliorations relatives aux critères d'évaluation se-condaires à 6 et 12 mois. Après une évaluation initiale des critères d'évaluation secondaires, les participants seront répartis aléatoirement dans le groupe suivant le programme à l'aide du vélo MedBIKE (36 séances réparties sur 12 semaines) ou dans le groupe recevant le traitement usuel. Tous les participants changeront ensuite de groupe, et une nouvelle évaluation des critères d'évaluation se-condaires sera effectuée. Les évaluations de suivi auront lieu 6 et 12 mois après la fin du programme. On s'attend à ce que ce dernier soit sûr, facile à suivre et accompagné d'améliorations soutenues de la tolérance à l'effort, du niveau d'AP, de la QVLS et de l'auto-efficacité à la pratique d'une AP chez les patients pédiatriques ayant reçu une transplantation cardiaque. Cette étude servira de modèle à un essai clinique croisé, multicentrique, à répartition aléatoire de plus grande envergure. Elle permettra aussi de générer des renseignements utiles pour les programmes de réadaptation destinés aux patients pédiatriques ayant reçu une transplantation cardiaque.

Genetic Contribution to End-Stage Cardiomyopathy Requiring Heart Transplantation.

BACKGROUND: Many cardiovascular disorders propel the development of advanced heart failure that necessitates cardiac transplantation. When treatable causes are excluded, studies to define causes are often abandoned, resulting in a diagnosis of end-stage idiopathic cardiomyopathy. We studied whether DNA sequence analyses could identify unrecognized causes of end-stage nonischemic cardiomyopathy requiring heart transplantation and whether the prevalence of genetic causes differed from ambulatory cardiomyopathy cases. METHODS: We performed whole exome and genome sequencing of 122 explanted hearts from 101 adult and 21 pediatric patients with idiopathic cardiomyopathy from a single center. Data were analyzed for pathogenic/likely pathogenic variants in nuclear and mitochondrial genomes and assessed for nonhuman microbial sequences. The frequency of damaging genetic variants was compared among cardiomyopathy cohorts with different clinical severity. RESULTS: Fifty-four samples (44.3%) had pathogenic/likely pathogenic cardiomyopathy gene variants. The frequency of pathogenic variants was similar in pediatric (42.9%) and adult (43.6%) samples, but the distribution of mutated genes differed (P=8.30×10-4). The prevalence of causal genetic variants was significantly higher in end-stage than in previously reported ambulatory adult dilated cardiomyopathy cases (P<0.001). Among remaining samples with unexplained causes, no damaging mitochondrial variants were identified, but 28 samples contained parvovirus genome sequences, including 2 samples with 6- to 9-fold higher levels than the overall mean levels in other samples. CONCLUSIONS: Pathogenic variants and viral myocarditis were identified in 45.9% of patients with unexplained end-stage cardiomyopathy. Damaging gene variants are significantly more frequent among transplant compared with patients with ambulatory cardiomyopathy. Genetic analyses can help define cause of end-stage cardiomyopathy to guide management and risk stratification of patients and family members.

Prospective examination of HLA sensitization after VAD implantation in children and adults.

BACKGROUND: Ventricular assist devices (VADs) have improved survival to heart transplantation (HTx). However, VADs have been associated with development of antibodies against human leukocyte antigen (HLA-Ab) which may limit the donor pool and decrease survival post-HTx. Since HLA-Ab development after VAD insertion is poorly understood, the purpose of this prospective single-center study was to quantify the incidence of and evaluate risk factors for HLA-Ab development across the age spectrum following VAD implantation. METHODS: Adult and pediatric patients undergoing VAD placement as bridge to transplant or transplant candidacy between 5/2016 and 7/2020 were enrolled. HLA-Ab were assessed pre-VAD and at 1-, 3-, and 12-months post-implant. Factors associated with HLA-Ab development post-VAD implant were explored using univariate and multivariate logistic regression. RESULTS: 15/41 (37%) adults and 7/17 (41%) children developed new HLA-Ab post-VAD. The majority of patients (19/22) developed HLA-Ab within two months of implant. New class I HLA-Ab were more common (87% adult, 86% pediatric). Prior pregnancy was strongly associated with HLA-Ab development in adults post-VAD (HR 16.7, 95% CI 1.8-158, p = 0.01). Of the patients who developed new HLA-Ab post-VAD, in 45% (10/22) the HLA-Ab resolved while in 55% (12/22) the HLA-Ab persisted. CONCLUSION: More than one-third of adult and pediatric VAD patients developed new HLA-Ab early after VAD implant with the majority having class I antibodies. Prior pregnancy was strongly associated with post-VAD HLA-Ab development. Further studies are needed to predict regression or persistence of HLA-Ab developed post-VAD, to understand modulation of individuals' immune responses to sensitizing events, and to determine whether transiently detected HLA-Ab post-VAD recur and have long-term clinical impact post-heart transplantation.

Impact of race and health coverage on listing and waitlist mortality in pediatric cardiac transplantation.

BACKGROUND: Social factors like race and insurance affect transplant outcomes. However, little is known in pediatric heart transplantation. We hypothesized that race and insurance coverage impact listing and waitlist outcomes across eras. METHODS: Data from the Pediatric Heart Transplant Society multi-center registry prospectively collected between January 1, 2000-December 31, 2019 were analyzed. Patients were divided by race as Black, White and other and by insurance coverage at listing (US governmental, US private and non-US single payer systems (UK, Canada). Clinical condition at listing and waitlist outcomes were compared across races and insurance coverages. Categorical variables were compared using a chi-square test and continuous variables using the Wilcoxon rank sum test. Risk factors for waitlist mortality were examined using multiphase parametric hazard modeling. A sensitivity analysis using parametric hazard explored the interaction between race and insurance. RESULTS: At listing, compared to Whites (n = 5391) and others (n = 1167), Black patients (n = 1428) were older, more likely on US governmental insurance and had cardiomyopathy as the predominant diagnosis (p < 0.0001). Black patients were more likely to be higher status at listing, in hospital, on inotropes or a ventricular assist device (p < 0.0001). Black patients had significantly shorter time on the waitlist compared to other races (p < 0.0001) but had higher waitlist mortality (p = 0.0091), driven by the earlier era (2000-2009) (p = 0.0005), most prominently within the US private insurance cohort (p = 0.015). Outcomes were not different in other insurance cohorts or in the recent era (2010-2019). CONCLUSION: Black children are older and sicker at the time of listing, deteriorate more often and face a higher wait list mortality, despite a shorter waitlist period and favorable clinical factors, with improvement in the recent era associated with the recent US healthcare reforms. The social construct of race appears to disadvantage Black children by limiting referral, consideration or access to pediatric cardiac transplantation.

Successful ABO incompatible heart transplantation after desensitization therapy in an older child.

BACKGROUND: ABO-incompatible heart transplantation (HTx) has become a standard procedure for children below 2 years of age due to an immunologically immature immune system and associated low isohemagglutinin titers. METHODS: We report a case of an ABO-incompatible HTx (recipient blood group O, donor blood group A) at the age of 5 years and 11 months with a fully matured immune system and previously high isohemagglutinin titers that diminished as a result of human leucocyte antigen (HLA) desensitization therapy with rituximab and immunoglobulins. RESULTS: The anti-A titer at the time of HTx was 1:16 with post-transplant isoagglutinin titers never exceeding 1:4 without any signs of rejection with now 3 years of post-HTx follow-up. CONCLUSIONS: ABO isohemagglutinin titers should be routinely assessed in children undergoing desensitization therapy since ABOi transplantation can be considered in selected cases to expand the donor pool with the option of crossing the ABO barrier to find a better-matched allograft.

Differences in medication adherence by sex and organ type among adolescent and young adult solid organ transplant recipients.

BACKGROUND: Identification of differences in medication adherence by sex or organ type may help in planning interventions to optimize outcomes. We compared immunosuppressive medication adherence between males and females, and between kidney, liver and heart transplant recipients. METHODS: This multicenter study of prevalent kidney, liver and heart transplant recipients 14-25 years assessed adherence 3 times (0, 3, 6 months post-enrollment) with the BAASIS self-report tool. At each visit, participants were classified as adherent if they missed no doses in the prior 4 weeks and non-adherent otherwise. Adherence was also assessed using the coefficient of variation (CV) of tacrolimus trough levels; CV < 30% was classified as adherent. We used multivariable mixed effects logistic regression models adjusted for potential confounders to compare adherence by sex and by organ. RESULTS: Across all visits, males (n = 150, median age 20.4 years, IQR 17.2-23.3) had lower odds of self-reported adherence than females (n = 120, median age 19.8 years, IQR 17.1-22.7) (OR 0.41, 95% CI 0.21-0.80) but higher odds of adherence by tacrolimus CV (OR 2.50, 95% CI 1.30-4.82). No significant differences in adherence (by self-report or tacrolimus CV) were noted between the 184 kidney, 58 liver, and 28 heart recipients. CONCLUSION: Females show better self-reported adherence than males but greater variability in tacrolimus levels. Social desirability bias, more common in females than males, may contribute to better self-reported adherence among females. Higher tacrolimus variability among females may reflect biologic differences in tacrolimus metabolism between males and females rather than sex differences in adherence. There were no significant differences in adherence by organ type.

Clinical approach to antibody-mediated rejection from the pediatric heart transplant society.

OBJECTIVE: This document is designed to outline the definition, pathogenesis, diagnostic modalities and therapeutic measures to treat antibody-mediated rejection in children postheart transplant METHODS: Literature review was conducted by a Pediatric Heart Transplant Society (PHTS) working group to identify existing pediatric and adult studies on antibody-mediated rejection (AMR). In addition, the centers participating in PHTS were asked to submit their approach to diagnosis and management of pediatric AMR. This document synthesizes information gathered from both these sources to highlight a practical approach to diagnosing and managing a child with AMR postheart transplant. This document may not represent the practice at all centers in the PHTS and serves as a starting point to understand an approach to this clinical scenario.

The experiences of children with a cardiac transplant, their families and health care providers in the COVID-19 pandemic.

BACKGROUND: The COVID-19 pandemic has had deleterious impacts on pediatric patients and families, as well as the healthcare providers who have attended to their care needs. METHODS: In this qualitative study, children with a cardiac transplant, as well as their families and healthcare providers were interviewed to explore the impact of the COVID-19 pandemic on pediatric care, as well as on patients' and their families' daily lives. Participants were recruited from a children's hospital in western Canada. Fifteen caregiving parents of transplanted children, 2 young patients, and 8 healthcare providers participated in interviews. RESULTS: Findings highlighted how families and their healthcare providers experienced pandemic-related shifts. Themes highlighted experiences, which entailed (1) initially hearing about the COVID-19 pandemic; (2) learning about their new reality; (3) adjusting to the pandemic; (4) adjusting to shifts in pediatric services; (5) evolving a view on the future, and (6) offering recommendations for cardiac care in a pandemic. CONCLUSIONS: Study implications emphasize the need to critically reflect on, and advance, methods of helping young patients and their families in pandemic circumstances, and supporting healthcare providers.

Patient and care provider inclusion in the development of an educational graphic novel for heart transplanted teenagers.

PURPOSE: Teenagers experience high rates of rejection and organ failure after heart transplantation due to non-adherence to medications, poor transition into adult care, and difficulties communicating with adults including healthcare providers. This project aimed to creatively bridge this gap-including teenage patients, their parents, and healthcare providers in the development of a new resource meant to motivate teenage heart-transplant-patients to take interest and ownership of their long-term health. METHODS: Four teenage heart-transplanted patients, four parents, and three healthcare providers provided insight into relevant content for an educational resource through semi-standardized questionnaires and interviews. Their input guided the style and substance of the resource developed under the supervision of Fine Arts professors and the pediatric heart transplant team. RESULTS: Parents and healthcare providers were concerned about teenagers' health choices and lack of perspective while patients were more bothered by parental nagging and being careful about infections than worrying about post-transplant risks. The resource that was developed therefore used subtlety within a narrative medium: a graphic novel that involved mutant worms, secret plots, and daring escapes, to address identified medical concerns and encouragements without triggering teenage resistance to instruction. CONCLUSION: The discrepancies between the priorities of healthcare providers, parents, and teenage heart-transplant-patients illustrate the significance of basing resource-development on input from the target population. We developed the first graphic novel written for teenage heart-transplant-patients with patient input and interdisciplinary cooperation, using the subtlety of a narrative medium as a model for integrating medical content within an appealing, motivational, patient-centered, and age-appropriate resource.

Ventricular assist device support following pediatric heart transplantation.

BACKGROUND: VAD support for early graft failure after HTx is a rare event in pediatrics. METHODS: We retrospectively describe our single-center experience with post-HTx VAD support in a cohort of patients transplanted between 01/05 and 12/20. RESULTS: Nine patients underwent VAD insertion in the early post-HTx period [median age 6.1 years (Range 0.3-20.3), median weight 17.6 kg (Range 3.5-65.0), and congenital heart disease (67%)]. Of the nine patients with early graft failure, almost half (44%) were implanted after 2015 and all of these patients had a pre-HTx plan for possible post-transplant VAD insertion. Time to VAD implant was a median of 0 day (Range 0-11). Total time on VAD support was a median of 12 days (Range 3.0-478.0). Two-thirds (n = 6; 67%) of the patients were weaned from support, retransplanted (11%) and two patients died (22%). In all of the patients where post-HTx VAD was anticipated there was 100% survival. CONCLUSIONS: In this small patient series, post-HTx VAD was a useful measure in selected patients especially with pre-HTx planning. However, more shared experiences to verify these findings are needed.

Heart Transplantation in Children With Down Syndrome.

Background Children with Down syndrome (DS) have a high risk of cardiac disease that may prompt consideration for heart transplantation (HTx). However, transplantation in patients with DS is rarely reported. This project aimed to collect and describe waitlist and post- HTx outcomes in children with DS. Methods and Results This is a retrospective case series of children with DS listed for HTx. Pediatric HTx centers were identified by their participation in 2 international registries with centers reporting HTx in a patient with DS providing detailed demographic, medical, surgical, and posttransplant outcome data for analysis. A total of 26 patients with DS were listed for HTx from 1992 to 2020 (median age, 8.5 years; 46% male). High-risk or failed repair of congenital heart disease was the most common indication for transplant (N=18, 69%). A total of 23 (88%) patients survived to transplant. All transplanted patients survived to hospital discharge with a median posttransplant length of stay of 22 days. At a median posttransplant follow-up of 2.8 years, 20 (87%) patients were alive, 2 (9%) developed posttransplant lymphoproliferative disorder, and 8 (35%) were hospitalized for infection within the first year. Waitlist and posttransplant outcomes were similar in patients with and without DS (P=non-significant for all). Conclusions Waitlist and post-HTx outcomes in children with DS selected for transplant listing are comparable to pediatric HTx recipients overall. Given acceptable outcomes, the presence of DS alone should not be considered an absolute contraindication to HTx.