Pediatric Heart Transplant Society Research Articles

Survival does not differ by annual center transplant volume-A Pediatric Heart Transplant Society Registry study.

There are conflicting data regarding the relationship between center volume and outcomes in pediatric heart transplantation. Previous studies have not fully accounted for differences in case mix, particularly in high-risk congenital heart disease (CHD) groups. We aimed to evaluate the relationship between center volume and outcomes using the Pediatric Heart Transplant Society (PHTS) Registry and explore how case mix may affect outcomes. A retrospective cohort study of all pediatric patients in the PHTS Registry who received a heart transplant from 2009 to 2018 was performed. Centers were divided into 5 groups based on average yearly transplant volume. The primary outcome was time to death or graft loss and outcomes were compared using Kaplan-Meier analysis. There were 4583 cases among 55 centers included. There was no difference in time to death or graft loss by center volume in the entire cohort (p = .75), in patients with CHD (p = .79) or in patients with cardiomyopathy (p = .23). There was also no difference in time to death or graft loss by center size in patients undergoing transplant after Norwood, Glenn or Fontan (log rank p = .17, p = .31, and p = .10 respectively). There was a statistically significant difference in outcomes by center size in the positive crossmatch group (p < .0001), though no discernible pattern related to high or low center volume. Outcomes are similar among transplant centers of all sizes, including for high-risk patient groups with CHD. Future work is needed to understand how patient-specific risk factors may vary among centers of various sizes and whether this influences patient outcomes.

Impact of prolonged ischemic time on pediatric heart transplantation outcomes: Improved outcomes in the most recent era

BackgroundImpacts of ischemic time (IT) on pediatric heart transplant outcomes are multifactorial. We aimed to analyze the effect of prolonged IT on graft loss after pediatric heart transplantation. We hypothesized that graft survival with prolonged IT has improved across eras. MethodsPatients <18 years old in the Pediatric Heart Transplant Society database (1993-2019) were included (N=6765) and stratified by diagnosis and era (1993-2004, 2005-2009, and 2010-2019). Severe graft failure (SGF) was defined as death, re-transplant, or need for mechanical circulatory support in the first 7 days post-transplant. Descriptive statistical methods were used to compare differences between patient characteristics and IT. Kaplan-Meier survival analysis compared freedom from graft loss, rejection, and infection. Multivariable analysis was performed for graft loss and SGF (hazard and logistic regression modeling, respectively). ResultsDiagnoses were cardiomyopathy (N=3246) and congenital heart disease (CHD; N=3305). CHD were younger, more likely to have an IT >4.5 hours, and more likely to require extracorporeal membrane oxygenation or mechanical ventilation at transplant (all P<0.001). Median IT was 3.6 hours [IQR 2.98 to 4.31; range 0-10.5]. IT was associated with early graft loss (HR 1.012, 95% CI 1.005-1.019), but not when analyzed only in the most recent era. IT was associated with SGF (OR 1.016 95%CI 1.003 - 1.030). ConclusionsDonor IT was independently associated with increased risk of graft loss, albeit with a small effect relative to other risk factors. Graft survival with prolonged IT has improved in the most recent era but the risk of SGF persists.

Uncertain benefit of statins in pediatric heart transplant recipients: A PHTS analysis

PurposeCardiac allograft vasculopathy (CAV) is a leading cause of graft failure in pediatric heart transplant recipients (HTRs). Early statin use has been shown to reduce CAV incidence and all-cause mortality in adult HTRs. We sought to evaluate the contemporary prevalence and trends of statin use in pediatric HTRs and the association between statin use with CAV development and graft failure. MethodsPatients <17 years of age at time of primary heart transplant who survived to ≥3 years without CAV were identified from the Pediatric Heart Transplant Society database (2001-2018). Statin use in the first 3 years post-transplant was defined as consecutive, intermediate, or absent. Kaplan Meier survival, multivariable modeling and propensity score-matched analyses evaluated associations between statin use and CAV incidence and graft survival, with sub-analyses performed on subjects age ≥10 at transplant. ResultsAmong 3485 (1086 age ≥10) HTRs, 584 (17%) received consecutive statin therapy, 647 (19%) intermediate use, and 2254 (65%) no statin. Statin use varied widely between sites, with increasing use in the ≥10-year-old cohort over time. By multivariate analysis, statin use was not associated with graft loss. Consecutive statin use was also not associated with graft survival or freedom from CAV development when compared to absent statin use in unmatched or propensity-matched analyses. ConclusionWhile statins remain commonly utilized in pediatric HTRs, early consecutive statin therapy did not decrease CAV incidence or graft loss. The differing effects of statins on CAV development and progression in pediatric vs. adult HTRs suggest differing risk and mediating factors and requires further study.

Abstract 14448: Graft Loss and Rejection Following COVID in Pediatric Heart Transplantation - A Pediatric Heart Transplant Society (PHTS) Propensity Matched Analysis

Introduction: While short-term outcomes following COVID among pediatric heart transplant (HT) recipients have been described, graft outcomes including the risks of subsequent graft loss and rejection following COVID are unknown. Hypothesis: We sought to determine the overall trends of post-HT survival during the COVID pandemic and determine if there was an increased risk for subsequent graft loss and/or rejection following post-HT COVID. Methods: All pediatric recipients of first HT between 1/2003-6/2022 in the Pediatric Heart Transplant Society ( PHTS) database were included. To assess if early post-HT survival changed during the COVID pandemic, 2-year HT survival was compared among those who underwent HT in 2014-2016, 2017-2019, and 2020-2022. To compare the risks of graft loss and rejection (acute cellular and/or antibody-mediated) between those with vs without post-HT COVID, a 1:2 (COVID vs non-COVID) propensity-score matched analysis using multiple pre-HT and post-HT factors (including exact matches for HT year and time post-HT) and Kaplan Meir analysis were performed. Patients with COVID within 3 months post-HT were excluded. Results: The 2-year post-HT survival was similar among patients who underwent HT across the 3 eras (Fig 1A). Among the overall 6634 patients (n = 888 [13%] with post-HT COVID), 861 patients with post-HT COVID and 1716 without post-HT COVID were included in propensity-score matching. There was no difference in the risk of subsequent graft loss (Fig 1B) or rejection (Fig 1C) among those with vs those without post-HT COVID. Conclusions: No differences were observed in early pediatric post-HT survival during the COVID pandemic compared to the immediately prior era. Post-HT COVID did not increase the risks of subsequent graft loss or rejection. Longer-term follow up is necessary to look at other potential post-HT COVID outcomes, such as coronary allograft vasculopathy.

Abstract 17159: Chronic Corticosteroid Immunosuppression in African American Pediatric Heart Transplant Recipients Does Not Improve Outcomes

Introduction: Previous studies consistently demonstrate worse outcomes for African American (AA) pediatric heart transplant (HT) recipients when compared to non-AA counterparts. Medical and social factors have been implicated in this discrepancy. As such, chronic corticosteroid use as maintenance immunosuppression for AA HT patients may be beneficial, though this has not been studied. Hypothesis: Chronic maintenance corticosteroid therapy does not decrease rejection or graft failure in AA pediatric HT recipients. Methods: We performed a retrospective analysis of the Pediatric Heart Transplant Society (PHTS) database for all HT recipients &lt;18 y.o. from January 1 st , 2007 to June 30 th , 2021. Retransplants and multiorgan transplants were excluded. Chronic steroid use was defined as taking oral steroids at one-year post-HT in the absence of rejection past 60 days post-HT to exclude patients who were on steroids for-cause. We used Kaplan-Meier and log-rank analyses for outcome comparisons among cohorts after the first year post-HT. Results: A total of 4099 patients were included, of which 780 (19%) were AA. Of the cohort, 756 (18.4%) were on chronic steroids. Within that group, 157 (20.1%) were AA. Patients on chronic steroids at individual centers ranged 0%-64.7% (median 11.5%, SD 16.9%), with no collective difference between steroid use in AA and non-AA patients. Freedom from rejection was worse in AA compared to non-AA patients, both in steroid and no steroid groups (p&lt;0.01). In the non-AA cohort, freedom from rejection was better in the no steroid group (p&lt;0.01). In the AA cohort, there was no statistical difference in rejection between the steroid and no steroid groups (p=0.20). Analyses of graft survival resulted in the same pattern. Conclusion: Use of Chronic steroids varies widely across pediatric HT centers, with no difference between AA and non-AA patients. AA patients have worse rejection and graft failure, and chronic steroid use did not affect these outcomes.

Abstract 13723: Waitlist Outcomes for Pediatric Heart Transplantation in the Current Era: An Analysis of the PHTS Database

Introduction: Waitlist mortality (WM) remains high in pediatric heart transplantation (HT). Allocation policy is a potential tool to help improve WM. This study aims to identify patients listed status 1A at highest risk for WM to potentially inform future allocation policy changes. Hypothesis: Significant variation in WM will exist even within highest urgency waiting status (1A). Methods: The pediatric heart transplant society database was queried for all patients &lt;18 years of age listed for HT between January 1, 2010 to December 31, 2021. WM was defined by death while awaiting transplant or being removed from the waitlist due to clinical deterioration. Kaplan-Meier analysis, log-rank testing, and Cox-proportional hazard models were created to determine association with WM. Subgroup analysis was performed in 1A patients based upon body surface area (BSA) at time of listing, cardiac diagnosis, and presence of mechanical circulatory support. Results: Among 5,974 children listed, 3928 (65.8%) were status 1A. Patients listed 1A had a higher burden of WM (p&lt;0.01) compared to patients listed status 1B or status 2. Among 1A patients, BSA&lt;0.3m 2 , congenital heart disease (CHD), and lower eGFR was associated with higher WM. VAD support at listing was associated with lower WM (figure, all p-values&lt;0.01) except in the single ventricle cohort (CHD-SV) (HR 2.13, p&lt;0.01). For BSA&lt;0.3m 2 listings, diagnosis other than dilated cardiomyopathy was associated with increased risk of WM . Prior cardiac surgery was associated with WM in the BSA 0.3-0.7m 2 and &gt;0.7m 2 groups. ECMO was associated with increased risk of WM in all cohorts (HR 2.26, p&lt;0.01). Conclusions: Significant variability exists in WM in patients listed 1A. Future changes to the pediatric allocation system should factor in the increased risk of WM in patients supported by ECMO, CHD-SV on VAD support, and small children with CHD, RCM or HCM.

Three decades of collaboration through the Pediatric Heart Transplant Society Registry: A journey through registry data with a highlight on children with single ventricle anatomy.

The Pediatric Heart Transplant Society (PHTS) Registry was founded 30 years ago as a collaborative effort among like-minded providers of this novel life-saving technique for children with end-stage heart failure. In the intervening decades, the data from the Registry have provided invaluable knowledge to the field of pediatric heart transplantation. This report of the PHTS Registry provides a comprehensive look at the data, highlighting both the longevity of the registry and one unique aspect of the PHTS registry, allowing for exploration into children with single ventricle anatomy. The PHTS database was queried from January 1, 1993 to December 31, 2019 to include pediatric (age < 18 years) patients listed for HT. For our analysis, we primarily analyzed patients by era. The early era was defined as children listed for HT from January 1, 1993 to December 31, 2004; middle era January 1, 2005 to December 31, 2009; and recent era January 1, 2010 to December 31, 2019. Outcomes after listing and transplant, including mortality and morbidities, are presented as unadjusted for risk, but compared across eras. Since 1993, 11 995 children were listed for heart transplant and entered into the PHTS Registry with 9755 listed during the study period. The majority of listings occurred within the most recent era. Waitlist survival improved over the decades as did posttransplant survival. Other notable changes over time include fewer patients experiencing allograft rejection or infection after transplant. Waitlist and posttransplant survival have changed dramatically in patients with single ventricle physiology and significantly differ by stage of single ventricle palliation. Key points from this PHTS Registry summary and focus on patients with single ventricle congenital heart disease in particular, include the changing landscape of candidates and recipients awaiting heart transplant. There is clear improvement in waitlist and transplant outcomes for children with both cardiomyopathy and congenital heart disease alike.

Risk factors for 1-year allograft loss in pediatric heart transplant patients using machine learning: An analysis of the pediatric heart transplant society database.

Pediatric heart transplant patients are at greatest risk of allograft loss in the first year. We assessed whether machine learning could improve 1-year risk assessment using the Pediatric Heart Transplant Society database. Patients transplanted from 2010 to 2019 were included. The primary outcome was 1-year graft loss free survival. We developed a prediction model using cross-validation, by comparing Cox regression, gradient boosting, and random forests. The modeling strategy with the best discrimination and calibration was applied to fit a final prediction model. We used Shapley additive explanation (SHAP) values to perform variable selection and to estimate effect sizes and importance of individual variables when interpreting the final prediction model. Cumulative incidence of graft loss or mortality was 7.6%. Random forests had favorable discrimination and calibration compared to Cox proportional hazards with a C-statistic (95% confidence interval [CI]) of 0.74 (0.72, 0.76) versus 0.71 (0.69, 0.73), and closer alignment between predicted and observed risk. SHAP values computed using the final prediction model indicated that the diagnosis of congenital heart disease (CHD) increased 1 year predicted risk of graft loss by 1.7 (i.e., from 7.6% to 9.3%), need for mechanical circulatory support increased predicted risk by 2, and single ventricle CHD increased predicted risk by 1.9. These three predictors, respectively, were also estimated to be the most important among the 15 predictors in the final model. Risk prediction models used to facilitate patient selection for pediatric heart transplant can be improved without loss of interpretability using machine learning.

Assessing Donor-Recipient Size Mismatch in Pediatric Heart Transplantation: Lessons Learned From Over 7,500 Transplants

BackgroundTo date, no studies have identified an optimal metric to match donor-recipient (D-R) pairs in pediatric heart transplantation (HT). ObjectivesThis study sought to identify size mismatch metrics that predicted graft survival post-HT. MethodsD-R pairs undergoing HT in Pediatric Heart Transplant Society database from 1993 to 2021 were included. Effects of size mismatch by height, weight, body mass index, body surface area, predicted heart mass, and total cardiac volume (TCV) on 1- and 5-year graft survival and morbidity outcomes (rejection and cardiac allograft vasculopathy) were evaluated. Cox models with stepwise selection identified size metrics that independently predicted graft survival. ResultsOf 7,715 D-R pairs, 36.0% were well matched (D-R ratio: −20% to +20%) by weight, 39.0% by predicted heart mass, 50.0% by body surface area, 57.0% by body mass index, 71.0% by height, and 93.0% by TCV. Of all size metrics, only D-R mismatch by height and TCV predicted graft survival at 1 and 5 years. Effects of D-R size mismatch on graft survival were nonlinear. At both 1 and 5 years post-HT, D-R undersizing and oversizing by height led to increased graft loss, with graft loss observed more frequently with undersizing. Moderately undersized donors by height (D-R ratio: <−30%) frequently experienced rejection post-HT (P < 0.001). Assessing D-R size matching by TCV, minimal donor undersizing was protective, while oversizing up to 25% was not associated with increased graft loss. ConclusionsIn pediatric HT, D-R appear most optimally matched using TCV. Only D-R size mismatch by TCV and height independently predicts graft survival. Standardizing size matching across centers may reduce donor discard.

Contemporary outcomes of pediatric cardiac transplantation with a positive retrospective crossmatch.

A positive crossmatch (+ XM) has traditionally been associated with adverse outcomes following pediatric heart transplantation. However, more recent studies suggest that favorable intermediate-term outcomes may be achieved despite a + XM. This study's hypothesis is that children with a + XM have similar long-term survival, but higher rate of complications such as rejection, coronary allograft vasculopathy (CAV), and infection, compared to patients with a negative (-) XM. The Pediatric Heart Transplant Society Registry (PHTS) database was queried from 2010-2021 for all patients <18 years of age with a known XM. Baseline demographics were compared between + XM and - XM groups using appropriate parametric and non-parametric group comparisons. Cox Proportional Hazards Modeling was used to identify risk factors for post-transplant graft loss, rejection, and CAV. Of 4599 pediatric heart transplants during the study period, XM results were available for 3914 (85%), of which 373 (9.5%) had a + XM. Univariate analysis showed lower 10-year survival for patients with + XM (HR = 1.3, p = .04). Multivariate analyses revealed no significant difference in 10-year survival in the 2 groups; however, time to first rejection (p = .0001) remained significantly shorter in the + XM group. Pediatric patients transplanted across a + XM experience earlier rejection; however, after multivariate adjustment, + XM is not independently associated with intermediate-term graft loss. The risk of heart transplantation against a + XM must be balanced with the ongoing risk of waitlist mortality.

Successful implementation of telehealth visits in the paediatric heart failure and heart transplant population.

The Advanced Cardiac Therapies Improving Outcomes Network (ACTION) and Pediatric Heart Transplant Society (PHTS) convened a working group at the beginning of 2020 during the COVID-19 pandemic, with the aim of using telehealth as an alternative medium to provide quality care to a high-acuity paediatric population receiving advanced cardiac therapies. An algorithm was developed to determine appropriateness, educational handouts were developed for both patients and providers, and post-visit surveys were collected. Telehealth was found to be a viable modality for health care delivery in the paediatric heart failure and transplant population and has promising application in the continuity of follow-up, medication titration, and patient education/counselling domains.

Single-drug immunosuppression is associated with noninferior medium-term survival in pediatric heart transplant recipients

Patients are usually maintained on at least 2 immunosuppressive drugs (ISDs) after the first year post heart transplant. Anecdotally, some children are switched to single-drug monotherapy (a single ISD) for various reasons and varying durations. Outcomes associated with differences in immunosuppression after heart transplantation are unknown for children. A priori we defined a noninferiority hypothesis for monotherapy compared to ≥2 ISDs. The primary outcome was graft failure, a composite of death and retransplantation. Secondary outcomes included rejection, infection, malignancy, cardiac allograft vasculopathy and dialysis. This international, multicenter, retrospective, observational cohort study used data from the Pediatric Heart Transplant Society. We included patients who underwent first-time heart transplant <18 years of age between 1999 and 2020 with ≥1 year of follow-up data available. Our analysis included 3493 patients with a median time post-transplant of 6.7 years. There were 893 patients (25.6%) switched to monotherapy at least once with the remaining 2600 patients always on ≥2 ISDs. The median time on monotherapy after the first year post-transplant was 2.8 years (range 1.1-5.9 years). We found an adjusted hazard ratio (HR) of 0.65 (95%CI: 0.47-0.88) favoring monotherapy compared to ≥2 ISDs (p=0.002). There were no meaningful differences in the incidence of secondary outcomes between groups, except for a lower rate of cardiac allograft vasculopathy in patients on monotherapy (HR 0.58, 95%CI: 0.45-0.74). For pediatric heart transplant recipients placed on monotherapy, immunosuppression with a single ISD after the first year post-transplant was noninferior to standard therapy with ≥2 ISDs in the medium term. Some children are switched to a single immunosuppressive drug (ISD) for various reasons after heart transplant, but outcomes associated with differences in immunosuppression are unknown for children. We assessed graft failure in children on a single ISD (monotherapy) compared to ≥2 ISDs in a cohort of 3493 children with a first heart transplant. We found an adjusted hazard ratio of 0.65 (95%CI: 0.47-0.88) favoring monotherapy. We concluded that for pediatric heart transplant recipients placed on monotherapy, immunosuppression with a single ISD after the first year post-transplant was non-inferior to standard therapy with ≥2 ISDs in the medium term.

The Fontan immunophenotype and post-transplant outcomes in children: A multi-institutional study.

Patients after Fontan palliation represent a growing pediatric population requiring heart transplant (HTx) and often have lymphopenia (L) and/or hypogammaglobinemia that may be exacerbated by protein-losing enteropathy (PLE, P). The post-HTx effects of this altered immune phenotype are not well studied. In this study of the Pediatric Heart Transplant Society Registry, 106 Fontan patients who underwent HTx between 2005 and 2018 were analyzed. The impact of lymphopenia and PLE on graft survival, infection, rejection, and malignancy was analyzed at 1 and 5 years post-HTx. The following combinations of lymphopenia and PLE were noted: +L+P, n=37; +L-P, n=23; -L+P, n=10; and -L-P, n=36. Graft survival between the groups was similar within the first year after transplant (+L+P: 86%, +L-P: 86%, -L+P: 87%, -L-P: 89%, p=.9). Freedom from first infection post-HTx was greatest among -L-P patients compared to patients with either PLE, lymphopenia, or both; with a 22.1% infection incidence in the -L-P group and 41.4% in all others. These patients had a significantly lower infection rate in the first year after HTx (+L+P: 1.03, +L-P: 1, -L+P: 1.3, -L-P: 0.3 infections/year, p < .001) and were similar to a non-single ventricle CHD control group (0.4 infections/year). Neither freedom from rejection nor freedom from malignancy 1 and 5 years post-HTx, differed among the groups. Fontan patients with altered immunophenotype, with lymphopenia and/or PLE, are at increased risk of infection post-HTx, although have similar early survival and freedom from rejection and malignancy. These data may encourage alternative immunosuppression strategies and enhanced monitoring for this growing subset of patients.

Waitlist and post-transplant outcomes for children with myocarditis listed for heart transplantation over 3 decades.

There is limited and conflicting information on waitlist and transplant outcomes for children with myocarditis. Retrospective review included children with myocarditis and dilated cardiomyopathy (DCM) listed for HT from January 01, 1993 to December 31, 2019 in the Pediatric Heart Transplant Society database. Clinical characteristics, waitlist and post-HT outcomes (graft loss, rejection, cardiac allograft vasculopathy, infection and malignancy) for children listed from early (1993-2008) and current era (2009-2019) with myocarditis were evaluated and compared to those with DCM. Of 9755 children listed, 322 (3.3%) had myocarditis and 3178 (32.6%) DCM. Compared to DCM, children with myocarditis in the early and the current era were significantly more likely to be listed at higher urgency; be in intensive care unit; on mechanical ventilation; extracorporeal membrane oxygenation and ventricular assist device (p < 0.05 for all). While unadjusted analysis revealed lower transplant rates and higher waitlist mortality for children with myocarditis, in multivariable analysis, myocarditis was not a risk factor for waitlist mortality. Myocarditis, however, was a significant risk factor for early phase post-HT graft loss (HR 2.46; p=0.003). Waitlist and post-HT survival for children with myocarditis were similar for those listed and transplanted in the early era to those listed and transplanted in the current era (p > 0.05 for both). Children with myocarditis have a higher acuity of illness at listing and at HT and have inferior post-HT survival compared to children with DCM. Outcomes for children with myocarditis have not improved over the 3 decades and efforts are needed to improve outcomes for this cohort.

Early aspirin use and the development of cardiac allograft vasculopathy in pediatric heart transplant recipients: A pediatric heart transplant society analysis.

Cardiac allograft vasculopathy (CAV) remains a leading cause of graft loss in pediatric heart transplant (HTx) recipients. Adult literature suggests that aspirin (ASA) use in the early post-HTx period may reduce the risk of CAV. This study aimed to determine the impact of early ASA use on the development of CAV in pediatric HTx recipients. All subjects <17 years of age at time of primary HTx who survived ≥3 years without evidence of CAV were identified for inclusion from the Pediatric Heart Transplant Society database (1996-2019). Early ASA use was defined as ASA started within the first 3 years post-HTx and was classified as continuous or intermittent. Frequency of ASA use was described across centers. Kaplan-Meier method assessed freedom from CAV and overall graft survival. Multiphase parametric hazard analyses and propensity score matched analysis were used to identify independent risk factors. 3,011 patients were included with 387 (13%) receiving continuous ASA, 676 (22%) receiving intermittent ASA, and 1,948 (65%) receiving no ASA. ASA use was highly variable across centers (0%-100%). At baseline patients receiving continuous ASA therapy demonstrated inferior graft survival (p < 0.001) and worse freedom from CAV (p=0.002), but with lower CAV grades (p=0.05). In multiphase parametric hazard modeling continuous ASA use was not independently associated with CAV, but remained associated with inferior graft survival. Propensity-matched sub-analysis between continuous and no ASA groups demonstrated no difference in freedom from CAV or overall graft loss. ASA use varies widely across pediatric HTx centers. Early ASA use did not reduce the risk of CAV or graft loss in pediatric heart transplant recipients.

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

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. 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. 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). 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.

Racial and socioeconomic disparities in pediatric heart transplant outcomes in the era of anti-thymocyte globulin induction.

Black race is associated with worse outcomes across solid organ transplantation. Augmenting immunosuppression through antithymocyte globulin (ATG) induction may mitigate organ rejection and graft loss. We investigated whether racial and socioeconomic outcome disparities persist in children receiving ATG induction. Using the Pediatric Heart Transplant Society registry, we compared outcomes in Black and White children who underwent heart transplant with ATG induction between 2000 and 2020. The primary outcomes of treated rejection, rejection with hemodynamic compromise (HC), and graft loss (death or re-transplant). We explored the association of these outcomes with race and socioeconomic disparity, assessed using a neighborhood deprivation index [NDI] score at 1-year post-transplant (high NDI score implies more socioeconomic disadvantage). The study cohort included 1,719 ATG-induced pediatric heart transplant recipients (22% Black, 78% White). There was no difference in first year treated rejection (Black 24.5%, White 28.1%, p=0.2). During 10 year follow up, the risk of treated rejection was similar; however, Black recipients were at higher risk of HC rejection (p=0.009) and graft loss (p=0.02). Black recipients had a higher mean NDI score (p < 0.001). Graft loss conditional on 1-year survival was associated with high NDI score in both White and Black recipients (p < 0.0001). In a multivariable Cox model, both high NDI score (HR 1.97, 95% CI 1.23-3.17) and Black race (HR 2.22, 95% CI 1.40-3.53) were associated with graft loss. Black race and socioeconomic disadvantage remain associated with late HC rejection and graft loss in children with ATG induction. These disparities represent important opportunities to improve long term transplant outcomes.

Clinical approach to vasoplegia in the transplant patient from the Pediatric Heart Transplant Society.

This manuscript outlines a clinical approach to vasoplegia incorporating the current state of knowledge regarding vasoplegia in pediatric patients immediately post-transplant and to identify modifiable factors both pre- and post-transplant that may reduce post-operative morbidity, end-organ dysfunction, and mortality. Centers participating in the Pediatric Heart Transplant Society (PHTS) were asked to provide their internal protocols and rationale for vasoplegia management, and applicable adult and pediatric data were reviewed. The authors synthesized the above protocols and literature into the following description of clinical approaches to vasoplegia highlighting areas of both broad consensus and of significant practice variation.

Clinical approach to mechanical circulatory support in the transplant patient from the Pediatric Heart Transplant Society.

The use of mechanical circulatory support (MCS) for pediatric patients who have undergone heart transplant has grown rapidly in the past decade. This includes support in the immediate post-transplant period and "rescue" therapy for patient later in their transplant course. Extracorporeal membrane oxygenation (ECMO) remains a standard modality of support for intraoperative concerns and for acute decompensation in the immediate post-transplant period. However, both pulsatile and continuous flow ventricular assist devices (VADs) have been used with increasing success in transplant patients for longer durations of support. Centers participating in the Pediatric Heart Transplant Society (PHTS) were queried to provide their internal protocols and rationale for mechanical circulatory support following heart transplant. These protocols coupled with evidence-based literature were used to provide the following description of clinical approaches to MCS in the transplant patient highlighting areas of both broad consensus and significant practice variation.

Race and Socioeconomic Bias in Pediatric Cardiac Transplantation

BackgroundTo date, no studies evaluated implicit bias among clinicians caring for children with advanced heart failure. ObjectivesThis study aims to evaluate implicit racial and socioeconomic bias among pediatric heart transplant clinicians. MethodsA cross-sectional survey of transplant clinicians from the Pediatric Heart Transplant Society was conducted between June and August 2021. The survey consisted of demographic questions along with explicit and validated race and socioeconomic status (SES) implicit association tests (IATs). Implicit and explicit biases among survey group members were studied and associations were tested between implicit and explicit measures. ResultsOf 500 members, 91 (18.2%) individuals completed the race IAT and 70 (14%) completed the SES IAT. Race IAT scores indicated moderate levels of implicit bias (mean = 0.33, d = 0.76; P < 0.001; ie, preference for White individuals). SES IAT scores indicated strong implicit bias (mean = 0.52, d = 1.53; P < 0.001; ie, preference for people from upper SES). There were weak levels of explicit race and wealth bias. There was a strong level of explicit education bias (mean = 5.22, d = 1.19; P < 0.001; ie, preference for educated people). There were nonsignificant correlations between the race and the SES IAT and explicit measures (P > 0.05 for all). ConclusionsAs observed across other health care disciplines, among a group of pediatric heart transplant clinicians, there is an implicit preference for individuals who are White and from higher SES, and an explicit preference for educated people. Future studies should evaluate how implicit biases affect clinician behavior and assess the impact of efforts to reduce such biases.