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The Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs), supported by the Society of Thoracic Surgeons, provides detailed information on pediatric patients supported with ventricular assist devices (VADs).From September 19, 2012, to December 31, 2021, there were 1,355 devices in 1,109 patients (19 years) from 42 North American Hospitals.Cardiomyopathy was the most common underlying etiology (58%), followed by congenital heart disease (CHD) (26%) and myocarditis (9%). Regarding device type, implantable continuous (IC) VADs were most common at 40%, followed by paracorporeal pulsatile (PP) (28%), and paracorporeal continuous (PC) (27%). Baseline demographics differed, with the PC cohort being younger, smaller, more complex (ie. CHD), and sicker at implant (P.0001). At six months post-VAD implantation, a favorable outcome (transplant, recovery, or alive on device) was achieved in 84% of patients, which was greatest among those on IC VADs (92%) and least for PC VADs (69%). Adverse events (AEs) were not uncommon, with non-gastrointestinal bleeding (incidence of 14%) and neurological dysfunction (11% [Stroke 4%]), within 2 weeks post implant being the most prevalent. Stroke and bleeding had negative impacts on overall survival (p=0.002 and p0.001, respectively).This Sixth Pedimacs Report demonstrates the continued evolution of the pediatric field. The complexity of cardiac physiologies and anatomical constraint mandates the need for multiple types of devices utilized (PC, PP, IC). Detailed analyses of each device type in this report provide valuable information to further advance the care of this challenging and vulnerable population.

The thirteenth annual report from The Society of Thoracic Surgeons (STS) Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) highlights outcomes for 27,314 patients receiving continuous flow durable left ventricular assist devices (LVAD) over the last decade (2012-2021). In 2021, 2,464 primary LVADs were implanted, representing a 23.5% reduction in the annual volume compared to peak implantation in 2019 and an ongoing trend from the prior year. This decline is likely a reflection of the untoward effects of the COVID-19 pandemic and the change in the US heart transplant allocation system in 2018. The last several years have been characterized by a shift in device indication and type with 81.1% of patients now implanted as destination therapy and 92.7% receiving an LVAD with full magnetic levitation in 2021. However, despite an older, more ill population being increasingly supported pre-implant with temporary circulatory devices in the recent (2017-2021) vs prior (2012-2016) eras, the 1- and 5-year survival continues to improve at 83.0% and 51.9%, respectively. The adverse events profile has also improved, with significant reduction in stroke, gastrointestinal bleeding, and hospital readmissions. Finally, we examined the impact of the change in heart transplant allocation system in 2018 on LVAD candidacy, implant strategy, and outcomes. In the competing outcomes analysis, the proportion of transplant eligible patients receiving a transplant has declined from 56.5% to 46.0% at 3 years, while the proportion remaining alive with ongoing support has improved from 24.1% to 38.1% at 3 years, underscoring the durability of the currently available technology.

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 subjects17 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 (p0.001) 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.

Heart transplantation (HT) is the gold standard for managing end-stage heart failure. Multiple quality metrics, including length of stay (LOS), have been used in solid organ transplantation. However, limited data are available regarding trends and factors influencing LOS after pediatric HT. We hypothesized that various donor, peri-transplant and recipient factors affect LOS after pediatric HT.We analyzed patients18years at time of HT from January 2005 to December 2018 in the Pediatric Heart Transplant Society database, and examined LOS trends, defined prolonged LOS (PLOS = LOS30days after HT), identified factors associated with PLOS and assessed outcomes.Of 4827 patients undergoing HT, 4414 patients were discharged and included for analysis. Overall median LOS was 19days[13,34]. Median LOS was longer in patients with congenital heart disease(CHD = 25days[15,43] than with cardiomyopathy(CM = 17days[12,27] across all ages. Median LOS in age1year was 26-days[16,45.5] and in age10year was 16days[11,26]. PLOS was seen in 1313 patients(30%). Patients with PLOS were younger, smaller and had longer CPB times. There was no difference in utilization of VAD at HT between groups, however, ECMO use at listing(8.45% vs 2.93%,p0.05) and HT was higher in the PLOS group(9.22% vs 1.58%,p0.05). PLOS was more common in patients with previous surgery, CHD, single ventricle physiology, recipient history of cardiac arrest or CPR, end organ dysfunction, lower GFR, use of mechanical ventilation at HT and Status 1A at HT.We present novel findings of LOS distribution and define PLOS after pediatric HT, providing a quality metric for individual programs to utilize and study in their practice.

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.

BACKGROUND Challenges exist with heterotaxy due to the complexity of heart disease, abnormal venous connections, and infection risks. This study aims to understand heart transplant outcomes for children with heterotaxy. METHODS All children with congenital heart disease listed for transplant from 1993 to 2018 were included. Those with and without heterotaxy were compared. Waitlist outcomes and survival post-listing and transplant were analyzed. Post-transplant risk factors were identified using multiphase parametric hazard modeling. RESULTS There were 4814 children listed, of whom 196 (4%) had heterotaxy. Heterotaxy candidates were older (5.8 ± 5.7 vs 4.2 ± 5.5 years, p < 0.01), listed at a lower urgency status (29.8% vs 18.4%, p < 0.01), more commonly single ventricle physiology (71.3% vs 59.2%, p < 0.01), and less often supported by mechanical ventilation (22% vs 29.1%, p < 0.05) or extracorporeal membrane oxygenation (3.6% vs 7.5%, p < 0.05). There were no differences in waitlist outcomes of transplant, death, or removal. Overall, post-transplant survival was worse for children with heterotaxy: one-year survival 77.2% vs 85.1%, with and without heterotaxy, respectively. Heterotaxy was an independent predictor for early mortality in the earliest era (1993-2004), HR 2.09, CI 1.16-3.75, p = 0.014. When stratified by era, survival improved with time. Heterotaxy patients had a lower freedom from infection and from severe rejection, but no difference in vasculopathy or malignancy. CONCLUSIONS Mortality risk associated with heterotaxy is mitigated in the recent transplant era. Early referral may improve waitlist outcomes for heterotaxy patients who otherwise have a lower status at listing. Lower freedom from both infection and severe rejection after transplant in heterotaxy highlights the challenges of balancing immune suppression.

Summary Background ABO-incompatible heart transplantation increases donor availability in young children and is evolving into standard of care in children younger than 2 years. Previous smaller studies suggest similar outcomes to ABO-compatible heart transplantation, but persisting alterations of the immune system in ABO-incompatible recipients might increase the risk of some infections or benefit the graft owing to reduced HLA reactivity. We aimed to assess long-term outcomes in young children after they received ABO-incompatible or ABO-compatible heart transplantation. Methods In this multicentre, prospective cohort study, we analysed data from the Pediatric Heart Transplant Society registry to compare children who received ABO-incompatible or ABO-compatible heart transplantation before age 2 years between Jan 1, 1999, and June 30, 2018. Given significantly different clinical demographics between the two groups, we also matched each ABO-incompatible recipient to two ABO-compatible recipients using propensity score matching. We assessed patient and graft survival, coronary allograft vasculopathy, malignancy, acute rejection (any episode resulting in augmentation of immunosuppression), and infections (requiring intravenous antibiotic or antiviral therapy or life-threatening infections treated with oral therapy). Findings We included 2206 children who received a heart transplant before age 2 years, with 11 332·6 patient-years of cumulative observation time. Children who received an ABO-incompatible transplant (n=364) were younger and a larger proportion had congenital heart disease and ventilator and mechanical circulatory support than the ABO-compatible recipients (n=1842). After matching, only differences in blood group (more O in ABO-incompatible and more AB in ABO-compatible groups) and use of polyclonal induction therapy with anti-thymocyte globulins persisted. The two matched groups had similar post-transplantation graft survival (p=0·74), freedom from coronary allograft vasculopathy (p=0·75), and malignancy (p=0·51). ABO-incompatible recipients showed longer freedom from rejection (p=0·0021) in the overall cohort, but not after matching (p=0·48). Severe infections (p=0·0007), bacterial infections (p=0·0005), and infections with polysaccharide encapsulated bacteria (p=0·0005) that share immunological properties with blood group antigens occurred less frequently after ABO-incompatible heart transplantation. Interpretation ABO-incompatible heart transplantation for children younger than 2 years is a clinically safe approach, with similar survival and incidences of rejection, coronary allograft vasculopathy, and malignancy to ABO-compatible recipients, despite higher-risk pre-transplant profiles. ABO-incompatible transplantation was associated with less bacterial infection, particularly encapsulated bacteria, suggesting that the acquired immunological changes accompanying ABO tolerance might benefit rather than jeopardise transplanted children. Funding Pediatric Heart Transplant Society.

The Society of Thoracic Surgeons (STS)-Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) 2020 Annual Report reviews outcomes on 25,551 patients undergoing primary isolated continuous-flow left ventricular assist device (LVAD) implantation between 2010 and 2019. In 2019, 3198 primary LVADs were implanted, which is the highest annual volume in Intermacs history. Compared with the previous era (2010-2014), patients who received an LVAD in the most recent era (2015-2019) were more likely to be African American (26.8% vs 22.9%, P

Management of infants with pulmonary atresia/intact ventricular septum (PA/IVS) is variable. Because of higher mortality in more severe forms, heart transplant (HT) is an acceptable approach, but waitlist and post-transplant outcomes are unclear. This study compared outcomes of infants with PA/IVS vs. other single ventricle (SV) anatomies listed for HT.Data from the Pediatric Heart Transplant Society (1993-2018) were analyzed for survival and risk factors for mortality.Of 1617 SV infants, 300 had PA/IVS (19%) and 1317 had other SV (81%). Overall, 1-, 5-, and 10-year survival was higher among PA/IVS (74%, 65%, 61%) versus other SV infants (62%, 54%, 50%, p = .004). While waitlist mortality was similar between groups (p = .09), PA/IVS was an independent predictor of improved waitlist survival (HR 0.68, p = .03), and PA/IVS infants had higher incidence of waitlist removal (8% vs. 5.5%, p = .03), most commonly for being "too well." Post-transplant survival was superior among PA/IVS versus other SV infants (1- and 5-year survival 93% and 81% vs. 80% and 71%, p .0001). Risk factors for PA/IVS waitlist mortality (2008-2018) included extracorporeal membrane oxygenation and mechanical ventilation. Prior aortopulmonary (AP) shunt among PA/IVS infants was associated with improved waitlist survival.Overall survival among PA/IVS infants listed for HT exceeds that of other SV infants with PA/IVS identified as an independent predictor of improved waitlist and post-transplant survival. Prior AP shunt among listed PA/IVS infants was associated with improved waitlist outcomes, though, which may reflect a listing selection bias.

Obesity and dyslipidemia afflict children of all ages. We explored the prevalence of obesity and dyslipidemia in pediatric heart transplant (HT) recipients and its effects on cardiac allograft vasculopathy (CAV) and survival.This study included primary HT recipients (≤18 years) transplanted between 01/1996 and 12/2018 included in the Pediatric Heart Transplant Society database. Obesity was categorized according to WHO/CDC guidelines and dyslipidemia according to the National Cholesterol Education Program. Kaplan-Meier analyses for CAV and graft loss stratified for BMI and lipid panels were generated and risk factors identified using multivariate analyses.Among 6291 HT patients (median age [range] at HT = 4.3 [0.6-12.8] years; 45% Female; 68% White), 56% had a normal BMI at HT. Obese patients at HT had an increased risk for graft loss (HR 1.19, 95% CI 1.01-1.4, p = .04). Poor total cholesterol (TC), LDL-C, and TG were associated with the risk of both CAV (HR 1.79, p .0001; HR 1.65, p = .0015; HR 1.53, p .0001, respectively) and graft loss (HR 1.58, p = .0008; HR 1.22, p = .04; HR 1.43, p = .0007, respectively).Pediatric patients who are obese at the time of HT and dyslipidemic at 1 year post-HT are at an increased risk for CAV and graft loss. Preventative interventions may reduce morbidity and mortality among this cohort.

Introduction: Rejection remains a significant cause of graft loss after heart transplantation. The current prevalence of recurrent rejection and its impact on graft loss after pediatric heart transplantation is unknown. Methods: All pediatric heart transplants between 1/2000-6/2020 in the Pediatric Heart Transplant Society database were included. Rejection was defined as a clinical event determined by biopsy, echocardiogram or clinical findings that resulted in augmentation of immunosuppression. Recurrent rejection was defined as ≥ 2 episodes of rejection after heart transplant. Freedom from recurrent rejection in the early (2000-2009) and current (2010-2020) era were compared. Multiphase parametric hazard modeling was utilized to understand the effects of each additional episode of rejection on graft loss in addition to identifying other risk factors. Results: Of 6342 heart transplants during the study period, 3921 (62%) had 0, 1386 (21%) had 1 and 1035 (17%) had ≥2 rejection episodes. In the current era, recurrent rejection is less frequent [468/4206 (11.1%) vs. 567/2136 (26.5%); p Conclusions: Currently, recurrent rejection is experienced by 1 in 10 pediatric HT recipients. Each additional episode of rejection post-HT confers an increasing risk for graft loss. Identifying risk factors for recurrent rejection is paramount to improving graft longevity.

The Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) provides detailed information on pediatric patients supported with ventricular assist devices (VADs).From September 19, 2012, to December 31, 2020, 1229 devices in 1011 patients were reported to the registry from 47 North American Hospitals in patients aged younger than 19 years.Cardiomyopathy was the most common underlying etiology (58%), followed by congenital heart disease (CHD; 25%) and myocarditis (10%). The most common devices implanted were implantable continuous (IC; 419 [41%]), followed by paracorporeal pulsatile (PP; 269 [27%]), paracorporeal continuous (PC; 263 [26%]), and percutaneous (53 [5%]). Overall, at 6 months after VAD implantation, 83% had a positive outcome (transplant, explant, or alive on device). The freedom from stroke at 3 months was highest in IC VADs (93%), compared with PP VADs (84%) and with PC VADs (75%). There were differences in survival by device type, with patients on IC VADs having the best overall survival and those on PC having the lowest overall survival, though the patient populations being supported by each VAD type differed significantly from each other.This Fifth Pedimacs Report demonstrates the continued robust growth of VADs in the pediatric community, now with more than 1000 patients reported to the registry. The multiple available device types (PC, PP, IC) serve different populations with different pre-VAD risk profiles, which may account for differences in survival and adverse events between device types.

Since 2012, there has been growing use of the HeartWare (Medtronic, Mounds View, MN) intracorporeal continuous flow (CF) ventricular assist device (VAD) in children, despite it not being labeled for use in pediatric patients. We sought to describe the use and outcomes of children with HeartWare VADs.We identified all patients aged19 years and young adults aged 19 to 30 years supported with HeartWare who were entered into the pediatric portion (Pedimacs) of the Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) and the Intermacs registries, respectively, between September 2012 and June 2017. Adverse events and outcomes were analyzed and compared.We identified 192 children and 247 young adult HeartWare patients. Baseline characteristics of children differed from young adults, with lower median weight of 51.5 kg (range, 13.1-162) vs 75.8 kg (range, 29.8-191; p ≤ 0.0001) and body surface area of 1.5 mSurvival in children supported with HeartWare is encouraging and comparable to young adults; however, adverse events are not uncommon in children. Ongoing evaluation of the HeartWare use in children is necessary to further decrease the rate of adverse events and understand obstacles to discharge.

To describe the impact of infectious adverse events (IAEs) during ventricular assist device (VAD) support on graft loss, infection, and rejection after pediatric heart transplant (HT). Pedimacs data were linked to Pediatric Heart Transplant Society (PHTS) data for patients receiving a VAD followed by HT between September 2012 and December 2016. Linked patients were categorized into IAE on VAD (group A) and no IAE on VAD (group B). Infectious adverse event locations included nondevice, device (external or internal), and sepsis. Post-HT outcomes for analysis were graft loss, infection, and rejection. Time-dependent analysis included Kaplan-Meier and multiphase parametric hazard function analysis. We linked 207 patients (age 9.4 ± 6.3 years). Post-HT follow-up was 19.4 patient-months (8 days-4.1 years). Group A included 42 patients (20%) with 62 IAEs. Group B included 165 patients without an IAE. Group A patients were younger (7.4 ± 6.1 vs. 9.5 ± 6.3 years; p = 0.03), waited longer for HT (5.3 ± 4.1 vs. 2.9 ± 2.5 months; p = 0.0005), and were hospitalized longer post-HT (42 ± 59 vs. 23 ± 22 days; p = 0.05). VAD-related IAEs were rare (N = 11). Groups A and B had similar freedom from first post-HT infection, rejection, and graft loss (all p0.1). However, patients with VAD-related IAE were somewhat more likely to experience rejection (p = 0.03) and graft loss (p = 0.01). Children with an IAE on VAD who survive to HT are younger, wait longer for HT, and remain hospitalized longer than those without an IAE on VAD. Overall, IAE on VAD did not impact post-HT outcomes, but VAD-related IAE may be associated with graft loss and rejection.

Retransplantation is rare and associated with worse survival and more morbidity. The study aim is to describe an updated cohort of pediatric retransplants, determine if there has been an era effect on outcomes, and understand if identified trends are explained by changes in patient selection.Pediatric Heart Transplant Society database analysis of retransplantation patients18 years of age (Era 1: 1993-2001, Era 2: 2002-2010, Era 3: 2011-2018). Multivariate analysis identified risk factors for graft loss. Multiphase parametric hazard modeling was used to depict era and risk factor effect.Survival was lower (p.0001) for retransplant (n = 222) compared to primary transplant (n = 6548) (median 9.3 vs 20.2 years). Median survival increased from Era 1 to 2 (4.8 vs 9.3 years; p.0001) with no incremental change in Era 3. Era 2 and 3 retransplants had a longer inter-transplant interval (p.0001), were less frequently for early graft failure (p = .0004) or acute rejection (p = .007), more frequently from a ventricular assist device (p = .0014), and less frequently from extracorporeal membrane oxygenation (p = .0024). Predictors of graft loss included Era 1 (HR 10.55, p = .001), congenital heart disease (HR 4.42, p = .01), inter-transplant interval1 year (HR 5.34, p = .002), and mechanical support (ventricular assist device HR 7.47, p = .0042; extracorporeal membrane oxygenation HR 10.09, p.0001). For each 1-year increase in inter-transplant interval, graft loss risk decreased by 1.15 (p = .0002). Retransplantation was associated with more rejection, infection, and allograft vasculopathy.Graft survival has improved in pediatric retransplants making it a viable option in select patients. Retransplantation should be avoided in the setting of early graft failure especially requiring mechanical support.

We sought to evaluate the association between timing of cardiac allograft vasculopathy (CAV) occurrence post-heart transplant (HT) with graft survival and progression of CAV severity in pediatric HT recipients.Data from the Pediatric Heart Transplant Society for pediatric (18 years old) HT recipients between 1993-2019 with available angiographic data were obtained (N = 5,075). The timing of CAV diagnosis (3; 3-5; 5-10; and ≥10 years post-HT) and severity of disease at each assessment (CAV 1-3) was determined. Associations between CAV timing, graft survival, and CAV progression were evaluated using Kaplan-Meier survival curves, multivariable COX proportional hazard regression analyses, and competing risk analyses.Over a median follow-up period of 4.1 (IQR 1.3-8.3) years, CAV was identified in 17% (885/5,075), 28% (252/885) of which were early-onset CAV. Compared with late onset CAV ≥10 years post-HT, patients with early CAV were older at the time of transplant (8.3 ± 6.2 vs. 3.8 ± 4.8 years, p.0001). While the five-year graft-survival in the ≥10-year group (79.2%, p = 0.03) was significantly higher than the3, 3-5, and 5-10 years post-HT groups (65.0%-67%) (p = 0.03), overall post-CAV graft survival was not significantly different across the CAV time-points. CAV disease progression did not vary with CAV timing post-HT, with an overall five-year freedom from CAV ≥2 of 75.4% (73.1%-77.6%).Later onset CAV (≥10-years post-HT) was associated with improved five-year graft survival compared with CAV onset at earlier time-points, but similar and poor long-term outcomes. CAV timing post-HT was not associated with progression of CAV disease severity.

While clinical status at the time of ventricular assist device (VAD) implant can negatively affect outcomes, it is unclear if early improvement after implant can have a positive effect. Therefore, the objectives of this study were to describe the clinical status of pediatric patients supported with a VAD and determine the impact of clinical status on the 1-month follow-up form on survival and ability to discharge. This was a retrospective analysis of data collected prospectively by the Pediatric Interagency Registry for Mechanical Circulatory Support Registry (Pedimacs) Registry. The Pedimacs database was queried for patients implanted between September 19, 2012, and September 30, 2019, who were alive on VAD support at 1-month postimplant on either a paracorporeal pulsatile or intracorporeal continuous device. Four factors on the 1-month follow-up were the focus of this study: mechanical ventilation, supplemental nutritional support, inotropic support, and ambulatory status. These factors were regarded as present if detected between 1-week and 1-month postimplant and were analyzed to determine their impact on survival following 1 month of VAD support and on successful discharge from hospital in patients with implantable continuous-flow devices. The eligible study cohort consisted of 414 patients with a mean age of 9.6 ± 6.2 years, weight of 40.8 ± 32.3 kg with the majority being male (56.7%) and having cardiomyopathy (68%). An isolated left ventricular assist device (LVAD) was the most common implant (85.5%). At implant, 40% were ventilated, 57% required nutritional support, 93% were on inotropes, and 58% were nonambulating. On the 1-month postimplant form, there were significant improvements in all four categories (14% ventilator support, 46% nutritional support, 53% on inotropes, and 25% nonambulating). However, there was no significant early change in the percentage of patients requiring supplemental nutrition in the paracorporeal pulsatile devices (88% vs. 82%; p = 0.2). Presence of these clinical parameters in early follow-up postimplant had a significant negative impact on survival and on the ability of patients with continuous-flow devices to be discharged. Presence of four specific clinical parameters early after VAD placement is associated with worse overall survival and an inability to discharge patients on VAD support. Ongoing work is needed for optimization of patients before implant and aggressive rehabilitation after implant to help improve long-term outcomes.

Background Freedom from rejection in pediatric heart transplant recipients is highly variable across centers. This study aimed to assess the center variation in methods used to diagnose rejection in the first-year post-transplant and determine the impact of this variation on patient outcomes. Methods The PHTS registry was queried for all rejection episodes in the first-year post-transplant (2010-2019). The primary method for rejection diagnosis was determined for each event as surveillance biopsy, echo diagnosis, or clinical. The percentage of first-year rejection events diagnosed by surveillance biopsy was used to approximate the surveillance strategy across centers. Methods of rejection diagnosis were described and patient outcomes were assessed based on surveillance biopsy utilization among centers. Results A total of 3985 patients from 56 centers were included. Of this group, 873 (22%) developed rejection within the first-year post-transplant. Surveillance biopsy was the most common method of rejection diagnosis (71.7%), but practices were highly variable across centers. The majority (73.6%) of first rejection events occurred within 3-months of transplantation. Diagnosis modality in the first-year was not independently associated with freedom from rejection, freedom from rejection with hemodynamic compromise, or overall graft survival . Conclusions Rejection in the first-year after pediatric heart transplant occurs in 22% of patients and most commonly in the first 3 months post-transplant. Significant variation exists across centers in the methods used to diagnose rejection in pediatric heart transplant recipients, however, these variable strategies are not independently associated with freedom from rejection, rejection with hemodynamic compromise, or overall graft survival.

Plastic bronchitis is a rare post-Fontan complication with limited treatment options. Heart transplantation has evolved as a potential curative option, but outcomes have not been well-defined. This study aims to assess contemporary waitlist and post-transplant outcomes in patients with plastic bronchitis. All Fontan patients were identified in the PHTS database (2010 - 2018). Waitlist and post-transplant outcomes were compared between Fontan patients with and without plastic bronchitis. Competing outcomes and Kaplan-Meier analyses were used to assess the impact of plastic bronchitis on waitlist and post-transplant survival. A secondary analysis excluded those with PLE from the comparison cohort. Of 645 Fontan patients listed for heart transplant, 69 (11%) had plastic bronchitis. At listing, patients with plastic bronchitis were younger (8.9 vs 11.1 years, P = .02), but had few other differences in baseline characteristics. A fewer Fontan patients with plastic bronchitis were listed in the more recent era (46 [15.4%] in 2010-2014 vs 23 [6.6%] in 2015-2018, P < .01). Overall, there was no difference in waitlist (P = .30) or post-transplant (P = .66) survival for Fontan patients with and without plastic bronchitis. The results were similar after excluding patients with PLE. Contrary to prior reports, this relatively large series showed that plastic bronchitis did not have a negative impact on survival to or after heart transplantation in Fontan patients. Our study also found a 50% reduction in listing in the current era, which may indicate evolution in management of Fontan patients.

Background Safe introduction of novel mechanical circulatory support (MCS) devices into clinical practice is a challenging process. Single-arm trials using a control arm from existing database is an effective alternative that could be applied for regulatory approval. This study analyzes the capability of the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) database to establish objective performance criteria and select patient population that could be used for future single-arm MCS trials. Methods Patients with INTERMACS profiles IM1-2 and IM3-5, who underwent implantation of isolated left ventricular assist devices between 2014 and 2017, were included. Both cohorts were further stratified into shock and nonshock groups using surrogate markers of shock (extracorporeal membrane oxygenation, temporary ventricular assist device, vasopressor infusions). Survival, transplantation rates, adverse events, 6-minute walk test, and quality-of-life measures were obtained for all 4 groups at 6 and 12 months. Results Total of 7907 patients were divided into IM1-2 (n = 3909), IM3-5 (n = 3998), shock (n = 3469), and nonshock (n = 3040) groups. Recategorization occurred in 11% of patients from the IM3-5 group into the shock group. Overall, patients in the shock group had similar outcomes to the IM1-2 group (1-year survival: 86% vs 85%; P = .74). Patients in the nonshock group also had similar outcomes to the IM3-5 (1-year survival: 90% vs 90%; P = .43). Conclusions The INTERMACS database can successfully establish objective performance criteria and concurrent control group for single-arm trials that could be used to support regulatory approval of new, less invasive MCS. INTERMACS data allow reliable comparisons of outcomes and adverse events.

Introduction: Traditional weight & height ratios as measures of donor-recipient (D-R) matching have been challenged in adult heart transplantation (HT). The optimal metrics for D-R matching in pediatric HT remain unclear, and were evaluated in the present study. Methods: All primary pediatric HT recipients in the Pediatric Heart Transplant Society database transplanted from 1993-2019 were included. Multiple metrics of size matching - height, weight, body mass index (BMI), body surface area (BSA), predicted heart mass (PHM) and total cardiac volume (TCV) were assessed to identify the metrics that would best predict 1-year post-transplant (PTx) graft loss (death/re-transplant). Kaplan-Meier analyses (risk unadjusted) and multivariate Cox proportional hazard models (risk adjusted) were used to assess the effect of differences of various size matching metrics on survival. Results: Among 6903 D-R pairs, multivariable hazard modeling identified the following risk factors for PTx mortality: female sex, black race, bilirubin, ECMO, VAD, mechanical ventilation, ICU admission at the time of transplant, presence of congenital heart disease, early era of transplant, donor ischemic time and cardiopulmonary bypass time. After adjusting for all covariates, increasing size mismatch by height, BSA, or PHM was associated with increased 1-year PTx graft loss, with a disproportionately higher hazard for undersized donors than oversized donors (Figure). Weight, BMI and TCV were not predictive of 1-year PTx graft loss on multivariate analysis. Conclusions: In pediatric HT recipients, increasing size mismatch by height, BSA and PHM is associated with increased 1-year PTx graft loss. Undersizing donors appears to carry a higher risk than oversizing.

Background: Pediatric heart transplant (TX) patients are at greatest risk of graft loss (GL) in the first year, which may increase due to accumulated risks in the pre-TX period. Machine learning (ML) may identify clinically relevant outcome characteristics without prior statistical assumptions. We assessed whether ML could improve risk assessment for one-year patient or graft survival in pediatric heart TX. Methods: Patients in the PHTS database from January 2010 to December 2016 and January 2017 to June 2019 were included in training (TRN) and testing (TST) sets, respectively. Primary outcome was time until death, GL, or censoring. Using TRN, we selected the 12 most important recipient predictors based on contributions to model fit by applying boosted decision trees. Proportional hazards, boosting, and oblique random survival forest models were developed using these predictors. Discrimination and calibration were compared at 1 year post-TX using TST. The contribution of each predictor to patient’s predicted log-hazard was estimated using SHapley Additive exPansion (SHAP) values. Results: TRN (N=2,686) included 1,368 (51%) patients with cardiomyopathy (CM), 1,247 (46%) with congenital heart disease (CHD), and 71 (2%) other. TST (N=1,101) included 509 (46%) with CM, 569 (52%) with CHD, and 23 (2.1%) other. Incidence of GL or death (95% CI) in TRN and TST was 8.13 (7.07, 9.25) and 9.04 (6.93, 11.3) events/100 person years. Among the three models fitted to TRN, boosting obtained the highest concordance index at 1-year post-TX in TST, 0.752 (95% CI 0.695-0.810), and exhibited no evidence of miscalibration. Primary diagnosis of non-CM was the strongest predictor according to the boosting model (mean SHAP 0.398), followed by cardiopulmonary bypass time (mean SHAP 0.308);( Figure 1 ). Conclusions: ML can identify salient predictor variables and develop generalizable risk prediction equations using data from pediatric TX patients and may improve patient selection.

Introduction: The shortage of available donor organs means we must re-consider our current policies on donor selection. There is a broad variation in practice between centers as to the acceptable limit to ischaemia time (IT) in pediatric cardiac transplantation, with no recommendations in international guidelines. Hypothesis: We hypothesised that a prolonged ischaemia time was not associated with impaired post-transplant outcomes. Methods: Data from the Pediatric Heart Transplantation Society was analysed for all pediatric patients receiving heart transplants (Jan 1993 - June 2019). Transplants were separated into 5 categories depending on the IT (hours): < 2.4, 2.5-3.4, 3.5-4.4, 4.5-6.0, >6. Risk-adjusted outcomes were assessed by multivariable analysis, adjusting for donor, recipient, and peri-operative characteristics. Results: Data for 6,903 transplants were assessed (IT < 2.4 in 980, 2.5-3.4 in 2032, 3.5-4.4 in 2310, 4.5-6.0 in 1162, >6 in 281). In univariate analysis, increasing IT was associated with reduced 1-year survival (90.1%, 87.7% and 84.6%; p6 groups, respectively. Similar findings, of a deleterious association with prolonged IT, were observed for freedom from infection (73.0%, 66.8% and 56.4%; p 6 hours was associated with graft failure in cardiomyopathy (HR: 2.87, 95% CI: 1.34 - 6.15, p=0.007), but not congenital heart disease patients. Conclusions: In this large multi-centre cohort study, we found a deleterious association between prolonged IT and post-transplant outcomes. We recommend that an IT greater than 6 hours should be avoided in pediatric cardiac transplantation.

Background Infants with heart failure remain at significant risk for wait list mortality, despite mechanical circulatory support (MCS). It is unclear if the outcomes are influenced by modality of support or underlying diagnosis. We sought to compare the outcomes of infants Methods and Results Using the Pediatric Heart Transplant Society database, we evaluated survival following first MCS device in children P =0.2; 5.4% versus 6.4%; P =0.4). However, there was a significant difference in the use of VAD both at listing (8% versus 2.4%; P P P P =0.01) for the CHD or the cardiomyopathy group ( P =0.38), but patients with cardiomyopathy demonstrated better survival on both forms of support. Conclusions Survival for patients

Background The Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs), originally a National Institutes of Health–sponsored U.S. database, provides a platform to understand the population of children supported with ventricular assist devices (VADs) during this time of increasing numbers, new devices, expanding indications, and improved outcomes. Methods Between September 19, 2012, and December 31, 2019, 44 hospitals implanted 1031 devices in 856 patients under 19 years of age. Results Overall, diagnosis was cardiomyopathy in 497 (58%) patients, congenital heart disease (CHD) in 216 (25%), myocarditis in 85 (10%), and other in 58 (7%). Positive outcome (alive on device or bridge to transplantation and recovery) occurred in 82% at 6 months. The patient cohort for implantable continuous (IC) pumps (n = 365) (age 13.2 ± 3.9 years, 18% Interagency Registry for Mechanically Assisted Circulatory Support [Intermacs] profile 1, 23% intubated at implantation, 16% with CHD) was significantly different from the paracorporeal continuous (PC) pump cohort (n = 212) (age 3.6 ± 4.9 years, 46% Intermacs profile 1, 81% intubated, 42% CHD) and the paracorporeal pulsatile (PP) pump cohort (n = 230) (age 2.7 ± 3.5 years, 31% Intermacs profile 1, 76% intubated, 26% CHD). Consistent with their cohort composition, positive outcomes at 6 months based on device type were the following: IC, 92%; PC, 68%; and PP, 81%. The incidence of cerebrovascular accidents in the IC, PC, and PP cohorts was 7%, 14%, and 15%, respectively. Conclusions IC VADs, the most common VAD type placed in children, are associated with improved outcomes compared with PP and PC devices, though PP and PC devices are limited to supporting our most challenging patients. Noteworthy, the incidence of cerebrovascular accidents for pediatric VADs has significantly decreased and is now 11% overall. This report demonstrates again that although often attributed to age, size, or device type, much of the burden in mortality and adverse events is correlated to the patient’s overall state at VAD implantation.

Coronary allograft vasculopathy (CAV) is a leading cause of mortality after heart transplantation (HT) in children. Variation in CAV screening practices may impact detection rates and patient outcomes.Among 50 Pediatric Heart Transplant Society (PHTS) sites from 2001 to 2016, coronary evaluations were classified as angiography or non-invasive testing, and angiograms were designated as routine or symptom based. CAV detection rates stratified by routine vs symptom-based angiograms were calculated. Freedom from CAV and mortality after CAV diagnosis, stratified by study indication, were calculated.A total of 3,442 children had 13,768 coronary evaluations; of these, 97% (n = 13,012) were for routine surveillance, and only 3% (n = 333) were for cause. Over the study period, CAV was detected in 472 patients (14%). Whereas 58% (n = 29) of PHTS sites evaluate by angiography alone, 42% reported supplementing with a non-invasive test, although only 423 non-invasive studies were reported. Angiographic detection of CAV was higher for symptom-based testing than for routine testing (29% vs 4%, p0.0001), although routine testing identified a majority of cases (88%; n = 414). The 10-year freedom from CAV was 77% overall. Once CAV is detected, 5-year graft survival was 58%, with lower survival for patients diagnosed after symptoms angiogram than after routine angiogram (30% vs 62%; p0.0001).Development of a robust model for CAV risk should allow low-risk patients to undergo less frequent invasive angiography without adverse impact on CAV detection rates or outcomes.

Background: Limited data are available regarding the outcomes of patients supported by extracorporeal membrane oxygenation (ECMO) who undergo durable mechanical circulatory support implantation (dMCS). We analyzed the clinical characteristics, outcomes, and risk factors for mortality in patients who were bridged with ECMO to dMCS. Methods: Adult patients who received dMCS between January 2008 and December 2017 (n=19 824), registered in the Society of Thoracic Surgeons-Interagency Registry for Mechanical Assisted Circulatory Support (STS-INTERMACS) database were included. Baseline characteristics, outcomes, risk factors, and adverse events were compared between ECMO-supported patients (n=933) and INTERMACS profile 1 (IP-1) patients not supported by ECMO (n=2362). A propensity match analysis was performed. Results: ECMO patients had inferior survival at 12 months (66.1%) than non-ECMO patients (75.4%; P P =0.49). A multiphase parametric hazard model identified 2 different periods based on risk of death. ECMO patients had a high hazard for death in the first 6 months after implantation (hazard ratio, 2.18 [1.79–2.66]; P P Conclusions: ECMO-supported patients before dMCS have lower survival compared with other IP-1 patients. A multivariable analysis showed that ECMO is an independent risk factor of poor outcome after dMCS. However, a propensity matched analysis suggested that when important clinical variables are controlled the outcome of both groups is similar. These data support the implantation of dMCS in carefully selected ECMO patients.

Background Fontan physiology results in multiorgan dysfunction, most notably affecting the liver and kidney. We evaluated the utility of Model for End-Stage Liver Disease Excluding INR (MELD-XI) score, a score evaluating the function of both liver and kidney to identify Fontan patients at increased risk for morbidity and mortality post–heart transplant. Methods The Pediatric Heart Transplant Society database was queried to identify Fontan patients listed for heart transplant between January 2005 and December 2018. MELD-XI scores were calculated at listing and heart transplant. A multivariable analysis was conducted to identify risk factors for post–heart transplant mortality. Demographic, clinical characteristics, and survival differences were evaluated and compared between the high and low MELD-XI score cohorts. The impact of changing MELD-XI scores during the waitlist period on post–heart transplant outcomes was also evaluated. Results Of 565 Fontan patients who underwent transplantation, 524 (93%) had calculable MELD-XI scores at the time of heart transplant: 421 calculable at listing and 392 calculable at listing and at heart transplant. On multivariable analysis, only MELD-XI score (squared) (hazard ratio, 1.007), history of protein-losing enteropathy (hazard ratio, 2.1), and ventricular assist device use at transplant (hazard ratio, 3.4) were risk factors for early phase post–heart transplant mortality. Patients with high MELD-XI scores at heart transplant had inferior survival post–heart transplant (P = .02); those in the high MELD-XI score cohort at wait listing and heart transplant tend to have the worst post–heart transplant survival; however, this was not significant (P = .42). Conclusions The MELD-XI, an easily calculated score, serves as a valuable aid in identifying pediatric Fontan patients at increased risk for post–heart transplant mortality.

BACKGROUND We sought to better understand the patient population who receive a temporary total artificial heart (TAH) as bridge to transplant or as bridge to decision by evaluating data from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) database. METHODS We examined data related to survival, adverse events, and competing outcomes from patients who received TAHs between June 2006 and April 2017 and used hazard function analysis to explore risk factors for mortality. RESULTS Data from 450 patients (87% men; mean age, 50 years) were available in the INTERMACS database. The 2 most common diagnoses were dilated cardiomyopathy (50%) and ischemic cardiomyopathy (20%). Risk factors for right heart failure were present in 82% of patients. Most patients were INTERMACS Profile 1 (43%) or 2 (37%) at implantation. There were 266 patients who eventually underwent transplantation, and 162 died. Overall 3-, 6-, and 12-month actuarial survival rates were 73%, 62%, and 53%, respectively. Risk factors for death included older age (p = 0.001), need for pre-implantation dialysis (p = 0.006), higher creatinine (p = 0.008) and lower albumin (p < 0.001) levels, and implantation at a low-volume center (≤10 TAHs; p < 0.001). Competing-outcomes analysis showed 71% of patients in high-volume centers were alive on the device or had undergone transplantation at 12 months after TAH implantation vs 57% in low-volume centers (p = 0.003). CONCLUSIONS Patients receiving TAHs have rapidly declining cardiac function and require prompt intervention. Experienced centers have better outcomes, likely related to patient selection, timing of implantation, patient care, and device management. Organized transfer of knowledge to low-volume centers could improve outcomes.

BACKGROUND Renal dysfunction (RD) is prevalent among pediatric patients with advanced heart failure. Data are limited regarding changes in renal function after left ventricular assist device (LVAD) placement in this population. METHODS Pediatric LVAD recipients enrolled in the Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) between September 19, 2012 and June 30, 2016 were included. Longitudinal changes in renal function were analyzed for the entire cohort as well as subgroups stratified by patient and device characteristics. Logistic regression was used to attempt to identify factors associated with lack of improvement in renal function after LVAD placement. Post-LVAD outcomes were assessed using the Kaplan‒Meier method. RESULTS Data from 247 patients from 39 centers were analyzed. Baseline RD (estimated glomerular filtration rate [eGFR]

Purpose Socioeconomic disparities negatively impacts outcomes in heart transplantation (HTx). However, the impact of insurance status and the social construct of race in pediatric patients has not been well studied. Methods The Pediatric Heart Transplant Society registry was queried between January 1, 2000- December 31, 2019. Patients were stratified by insurance status: US government (USG), US private (USP) and Single Payer (SP, UK & Canada) and race (black, white, other). Patients with a selection of more than one race were classified as other. Outcomes after HTx were assessed by Kaplan Meier log rank test including graft survival, time to first cardiac allograft vasculopathy (CAV), rejection, hemodynamic compromised (HC) rejection, and malignancy. Results 5879 children underwent HTx with insurance status as follows: 2800 USG (48%), 2431 USP (41%) and 648 SP (11%). Race breakdown included: 4086 white, 1052 black and 936 other. At 10 years post-transplant, graft survival (65.8% USG, 72.6% USP, 77% SP, p= .0005), time to first CAV (73.5% USG, 77.7% USP, 94.6% SP, p Conclusion In this multinational analysis of pediatric HTx patients, USG was associated with worse post-HTx outcomes. When stratified by race, graft survival was worse in black patients with USG and USP insurance. Both insurance and the social construct of race contribute to worse outcomes post heart transplant and may represent disparity in access to care and other racial bias. These results highlight the importance of further work in this area.

Historically, the "temporary" or short-term ventricular assist device (VAD) was used only as a quick bridge to recovery for children with an acute process. In the current era, the devices that were originally used for temporary support are now being used to support children for longer durations and for a variety of indications. In this study we aimed to describe the overall use, patients' characteristics and outcomes of "temporary" VAD use in children.The Pediatric Interagency Registry for Mechanical Circulatory Support (PediMACS) is a National Institutes of Health-supported national registry for United States Food and Drug Administration-approved VADs in patients19 years of age at the time of VAD implantation (either durable or temporary VAD). Patients undergoing placement of a device classified as a temporary VAD between September 19, 2012 and June 30, 2016 were included.Temporary VADs were implanted in 63 patients at 20 centers, accounting for 19% of all pediatric VAD patients entered into PediMACS. The median age at implantation was 3.7 (range1 day to 18) years. The underlying diseases were: congenital heart disease in 26 (41%), 20 of whom were classified as single ventricle; cardiomyopathy in 25 (40%); and myocarditis/rejection in 12 (19%). Patients were predominately Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Profile 1 (51%), and 10 patients (16%) had previously been supported with extracorporeal membrane oxygenation. Median duration of support was 15 (range1 day to 227) days, with 41 patients (65%) being on support for ≥10 days. The most frequent adverse events were bleeding (29% of patients) and neurologic dysfunction (24% of patients). Overall, 71% (45) achieved a positive outcome (defined as bridge to recovery [30%], transplantation [17%], alive on device [2%] or transition to durable VAD [22%]). Eighty-eight percent (n = 22) of the cardiomyopathy patients and 60% (n = 12) of the single-ventricle patients achieved a favorable outcome.Devices historically classified as "temporary" pumps are being used not only as a short-term mechanical circulatory support strategy but also as a longer term support strategy. In this multi-institutional, high-acuity, complex patient cohort, the use of "temporary" VADs resulted in a positive outcome (bridge to transplant, recovery durable device or alive) in 71% of patients.

Adults with congenital heart disease represent an expanding and unique population of patients with heart failure (HF) in whom the use of mechanical circulatory support (MCS) has not been characterized. We sought to describe overall use, patient characteristics, and outcomes of MCS in adult congenital heart disease (ACHD).All patients entered into the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) between June 23, 2006, and December 31, 2015, were included. Patients with ACHD were identified using pre-operative data and stratified by ventricular morphology. Mortality was compared between ACHD and non-ACHD patients, and multivariate analysis was performed to identify predictors of death after device implantation.Of 16,182 patients, 126 with ACHD stratified as follows: systemic morphologic left ventricle (n = 63), systemic morphologic right ventricle (n = 45), and single ventricle (n = 17). ACHD patients were younger (42 years ± 14 vs 56 years ± 13; p0.0001) and were more likely to undergo device implantation as bridge to transplant (45% vs 29%; p0.0001). A higher proportion of ACHD patients had biventricular assist device (BiVAD)/total artificial heart (TAH) support compared with non-ACHD patients (21% vs 7%; p0.0001). More ACHD patients on BiVAD/TAH support were INTERMACS profile 1 compared with patients on systemic left ventricular assist device (LVAD) support (35% vs 15%; p = 0.002). ACHD and non-ACHD patients with LVADs had similar survival; survival was worse for patients on BIVAD/TAH support. BiVAD/TAH support was the only variable independently associated with mortality (early phase hazard ratio 4.4; 95% confidence interval, 1.8-11.1; p = 0.001). For ACHD patients receiving MCS, ventricular morphology was not associated with mortality.ACHD patients with LVADs have survival similar to non-ACHD patients. Mortality is higher for patients requiring BiVAD/TAH support, potentially owing to higher INTERMACS profile. These outcomes suggest a promising role for LVAD support in ACHD patients as part of the armamentarium of therapies for advanced HF.

Background Expanded use of pediatric ventricular assist devices (VADs) has decreased mortality in children awaiting heart transplantation. Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs), a National Heart, Lung, and Blood Institute–sponsored North American database, provides a platform to understand this emerging population. Methods Between September 2012 and September 2016, patients aged younger than 19 years who underwent VAD implantation were enrolled in Pedimacs. FDA approved durable devices as well as temporary support devices were included. The second annual report updates the current Pedimacs data. Patients implanted with temporary devices are included in Pedimacs and this analysis includes this group of paracorporeal continuous flow VADs. Results Over the 4 years, 42 hospitals implanted 432 devices in 364 patients less than 19 yrs of age. Diagnoses included cardiomyopathy in 223 (61%), myocarditis in 41 (11%), and congenital heart disease in 77 (21%), of which 48 had single-ventricle physiology. At implant, 87% were at Intermacs patient profile 1 or 2. The age distribution of children (59% male) supported on VAD included 69 (19%) aged younger than 1 year, 66 (18%) aged 1 to 6 years, 56 (15%) aged 6 to 10 years, and 173 (48%) aged 11 to 19 years. Median follow-up was 2.2 months (range, 1 day to 41.5 months). Median (interquartile) age at implant was 1.7 (0.3–10.0) years for paracorporeal continuous-flow pumps ( n = 60), 1.7 (0.4–5.3) years for paracorporeal pulsatile pumps ( n = 105), and 15.0 (11.3–16.9) years for implantable continuous-flow pumps ( n = 174). Support strategies included LVAD in 293 (80%), biventricular device in 55 (15%), and total artificial heart in 8 (2%). Nearly 50% of patients underwent transplantation within 6 months, with overall mortality of 19%. Adverse event burden continues to be high. Conclusions Pedimacs constitutes the largest longitudinal pediatric VAD registry. Preimplant data across centers will be helpful at creating shared protocols with which to improve outcomes. Adverse events continue to be the major challenge, especially among the young critically ill children with complex congenital disease.

Purpose Plastic bronchitis is a rare post Fontan complication with limited treatment options. Heart transplantation has evolved as a potential curative option, but outcomes have not been well-defined. This study aims to assess contemporary waitlist and post-transplant outcomes in patients with plastic bronchitis. Methods All Fontan patients were identified in the Pediatric Heart Transplant Society database (2010-2018). Waitlist and post-transplant outcomes were compared between Fontan patients with and without plastic bronchitis. Competing outcomes and Kaplan Meier analyses were used to assess the impact of plastic bronchitis on waitlist and post-transplant survival. A secondary analysis excluded those with protein losing enteropathy (PLE) from the comparison cohort. Results Of 645 Fontan patients listed for heart transplant, 69 (8%) had plastic bronchitis. At listing, patients with plastic bronchitis were younger (9.2 vs 10.6 years, p=0.02), but had no other differences at baseline including hemodynamic data. Fewer Fontan patients with plastic bronchitis were listed in the more recent era (46 [15.4%] in 2010-2014 vs. 23 [6.6%] in 2015-2018, p Conclusion Contrary to prior reports, in this large series plastic bronchitis did not have a negative impact on survival to or after heart transplantation in Fontan patients. A 50% reduction in listing in the most recent era suggests improvement in medical management of this rare and life-threatening condition.

Purpose The obesity epidemic has afflicted children of all ages with heart transplant (HT) recipients at significant risk compared to their pediatric counterpart. This study is the first large scale study to evaluate the prevalence of obesity in pediatric HT recipients and its effects on cardiac allograft vasculopathy (CAV) and graft survival. Methods We evaluated pediatric HT recipients (age 2 years) and weight/length z score >95%ile (WHO guidelines; age Results 4756 pediatric HT patients (pts) met study criteria (mean age at 1 year post-HT = 6.7 ± 6.2 yrs; 44.6% female; 69.5% White). At HT, 56% had a normal weight, 10% were overweight, 11% were obese and 23% were underweight. Overall, ∼60% had normal BMI that remained consistent up to 15 years post-HT (56-69%). For obese pts at HT, there was an increased risk for CAV development (HR 1.5, p = 0.002) and graft loss (HR 1.3, p = 0.001), see Figure. The risk of CAV development remained significant for obese pts at 5 years post-HT (p Conclusion Only 60% of pediatric HT recipients had ideal BMI at 1 year and 5 year follow up. Obesity at HT predicts an increased risk of CAV and graft loss. Exploring metabolic risk factors that lead to CAV development and graft loss are important. Healthy lifestyle interventions pre-HT and during HT follow up may potentially reduce morbidity and mortality.

Heart transplantation from ABO incompatible (ABOi) donors has evolved into a progressively accepted therapy in young children. We assessed the recent practice of ABOi listing impact on waitlist and post-transplant outcomes.Using the Pediatric Heart Transplant Society registry, we compared clinical presentation, waitlist parameters, and post-transplant survival of children2 years of age listed for ABOi vs ABO compatible (ABOc) heart transplant between January 2010 and June 2018 with sub-analysis of blood group O recipients.Among 2,039 patients, ABOi listing increased significantly with time from 49% (2010) to 72% (2017). ABOi-listed patients had lower age and body surface area, and higher proportion of congenital heart disease, mechanical ventilation, and high urgency status (all p0.01). Use of mechanical circulatory support was similar between groups. Of 1,288 patients reaching transplant, 239 (18.6%) received an ABOi organ (15%-40%/year). Death while waiting, removal from the waitlist, and waitlist survival were similar between groups. Time to transplant was significantly shorter for ABOi listing in blood group O patients (p0.02), approaching significance (p = 0.057) for all blood groups. Post-transplant survival was similar except for lower survival of patients listed ABOc but transplanted ABOi. These patients showed increasing need for mechanical circulatory support and high urgency listing while waiting.In the current era, primary listing for ABOi heart transplant has become routine for the majority of children2 years old, resulting in shorter waitlist time, especially in blood group O. Post-transplant survival is similar despite ABOi-listed children still showing a higher risk profile.

Purpose Cardiac allograft vasculopathy (CAV) has limited treatment options and results in significant mortality. Data in adult heart transplant (HTx) recipients suggests that aspirin (ASA) use may reduce the risk of CAV. However, there are limited pediatric data on this topic. This study aimed to assess the use of ASA in pediatric HTx recipients and its association with CAV. Methods All patients in the Pediatric Heart Transplant Society database > 3 years of follow up were included. ASA use during the first 3 years post-transplant was defined as continuous, intermittent, or no ASA use. Time to CAV and graft loss was compared across groups using the Kaplan Meier method. A multivariable survival model was constructed for each outcome to assess the impact of early post-HTx ASA use. Results A total of 3,011 patients were identified for inclusion with 387 (13%) continuous, 676 (22%) intermittent, and 1948 (65%) with no ASA use. ASA use was more common in older patients (p Conclusion ASA use varies widely across pediatric HTx centers. Early ASA use did not reduce the risk of CAV or graft loss.

Purpose Ventricular assist device (VAD) use in patients with congenital heart disease continues to increase. However, the outcomes of supporting a Fontan circulation with a VAD are largely unknown. Methods This is a retrospective review of the Pedimacs and Intermacs databases. 55 patients underwent systemic VAD implant to support the Fontan circulation between September 2012 and December 2019. Results The mean age of patients at implantation was 12.2 ± 8.0 yrs, and mean weight, 38.1 ± 26.8 kgs. Patient demographics are presented in Table 1. 28 more VADs were implanted in 2018-2019 than in 2012-2017 (28 vs 27, P = 0.007, Figure 1). The later era had higher GFR (101.1 ± 48.5 vs 71.2 ± 34.9 P = 0.02) and were more likely being followed for heart failure prior to VAD (96% vs 74% P = 0.02), but there was no difference in INTERMACS profile (P = 0.69). Kaplan-Meier survival on device was 76% at 6 months with no difference by era. Competing outcomes demonstrated a positive outcome of 81% (alive on VAD, transplanted or recovered) at 6 months, with the majority of mortality occurring in month one. Mean length of support was 5.5 ± 8 mos. 5 patients were supported for >1 yr with no added mortality; the longest support time was 4 yrs 7mos. Adverse event rates included pump thrombosis incidence of 4% (3.3/100 pt-mo), GI bleeding of 7% (2.6/100 pt-mo), and non-GI bleeding of 9% (2.3/100 pt-mo). Freedom from stroke and infection were both 95% at 6 months. Conclusion This is the largest reported analysis of systemic VAD support of Fontan patients. Mechanical circulatory support of the Fontan circulation is increasing in prevalence and can be performed with promising outcomes.

Purpose Our study aims to identify the utility of pre-implant MELD-XI score in identifying pediatric patients at higher risk for morbidity and mortality post-VAD implant. Methods We reviewed all patients listed in the PediMACS database from 9/19/12 to 3/31/19. Patients missing bilirubin or creatinine that precluded calculation of MELD-XI score (n=89) were excluded. Patients were divided into three cohorts based on MELD-XI score pre-implant - low (minimum score 9.4, 13.6, 75-100%-tile). Baseline clinical and hemodynamic data were compared; outcomes data on morbidity and mortality were compared across groups. Results Of 596 patients included, 42.5% were in the low, 29.2% in the intermediate and 28.3% in the high MELD-XI cohort. Compared to the low and intermediate cohorts, patients in the high MELD-XI cohort were significantly older (p Conclusion Pediatric patients with an elevated MELD-XI score have higher acuity of illness pre-implant. This easily calculated score based on routinely collected lab values serves as a promising risk assessment tool in identifying pediatric VAD recipients at increased risk for mortality post VAD implant. Trending the MELD-XI score in patients with advanced heart failure may aid clinicians in timing of VAD implantation.

Dyslipidemia in the pediatric heart transplant (HT) population carries significant risk for developing cardiac allograft vasculopathy (CAV), one of the primary reasons for heart retransplantation (retx). This large-scale pediatric study sought to evaluate the prevalence of dyslipidemia and its

BACKGROUND The use of ventricular assist devices (VADs) in children with heart failure may be of particular benefit to those with accompanying renal failure, as improved renal function is seen in some, but not all recipients. We hypothesized that persistent renal dysfunction at 7 days and/or 1 month after VAD implantation would predict chronic kidney disease (CKD) 1 year after heart transplantation (HT). METHODS Linkage analysis of all VAD patients enrolled in both the PEDIMACS and PHTS registries between 2012 and 2016. Persistent acute kidney injury (P-AKI), defined as a serum creatinine ≥1.5× baseline, was assessed at post-implant day 7. Estimated glomerular filtration rate (eGFR) was determined at implant, 30 days thereafter, and 12 months post-HT. Pre-implant eGFR, eGFR normalization (to ≥90 mL/min/1.73 m2 ), and P-AKI were used to predict post-HT CKD (eGFR

BACKGROUND The reported ventricular assist device (VAD) experience in the pediatric congenital heart disease (CHD) population is limited. We sought to describe contemporary use and outcomes of VADs in children with CHD and compare these outcomes to those of non-CHD children. METHODS Patients enrolled in the Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) between September 19, 2012 through June 30, 2017 were included. CHD was classified as biventricular vs single ventricle (Stages 1, 2, or 3). Outcomes were compared between groups and multivariable analysis was used to identify factors associated with mortality on the device. RESULTS Among the 471 patients enrolled, 108 (24%) had CHD (45 biventricular and 63 single ventricle). CHD patients were younger (5.7 ± 5.7 years vs 9.8 ± 6.5 years; p < 0.0001) and smaller (0.8 ± 0.5 m2 vs 1.2 ± 0.7 m2; p < 0.0001) compared with non-CHD patients. CHD patients were more likely to receive a paracorporeal continuous-flow VAD (36.1% vs 12.9%; p < 0.0001) and less likely to receive an implantable continuous-flow VAD (27.8% vs 55.0%; p < 0.0001) compared with non-CHD patients. After 6 months on a VAD, CHD patients had higher mortality (36.4% vs 12.1%) and a lower transplantation rate (29.1% vs 59.9%) than non-CHD patients (p < 0.0001). In the multivariable analysis, CHD was the factor most strongly associated with mortality on VAD (hazard ratio [HR] = 2.9; p < 0.0001), whereas the factors implantable continuous-flow device and high-volume center were protective (HR = 0.3, p < 0.0001, and HR = 0.6, respectively; p = 0.02). CONCLUSIONS VAD use in children with CHD is associated with increased mortality and decreased transplant rates compared to children without CHD. For the subgroup of children with CHD who received implantable continuous-flow VADs, survival rates were higher and comparable to those of children without CHD. Increased experience correlated with better survival in pediatric VADs.

Purpose Future durable MCS devices are designed to be less invasive, delivered via non-central arterial access and provide partial support. They will be true assist devices and require residual cardiac reserve, ie. the “less sick” advanced CHF population. Lacking equipoise to perform randomized trials with approved LVADs, single arm trials with OPC will be needed to get regulatory approval. This study analyzes IM for completeness and validity and to determine its ability to 1) define the real-world “less sick” patient group and 2) establish OPCs for future MCS trials. Methods Inclusion - IM patients > 45 years, profiles 1-5 and implanted between 2014-2016 with durable LVADs. Patients were stratified into IM1-2 and IM3-5 groups. They were also stratified to real-world sick (S) and less sick (LS) groups using pre-implant hemodynamics (CI 20 mmHg) and the amount of inotropic/temporary MSC support. Survival, transplant rates, adverse events, 6 min walk test and KCCQ were obtained for the 4 groups at 6 and 12 months. Results 6509 patients met inclusion criteria. Patients were grouped into IM1-2 (n=3084), IM3-5 (n=3425), S (n=4026), and LS (n=1808). Re-categorization occurred in 11% from IM1-2 to LS and 43% from IM3-5 to S. 675 patients (10%) could not be placed into the S or LS groups due to lack of pre-implant hemodynamic data. Outcomes (survival, transplanted, death) at 6 and 12 months were similar between the S group and IM1-2 group as well as the LS group and IM3-5 group. Outcomes, adverse events and performance status are reported in table 1. Conclusion Patients in the IM database can be classified by hemodynamic assessment and inotrope/temporary MCS support into a better defined LS patient group than using physician assigned profiles. Interestingly, AEs and outcomes were similar across groups reflecting class effects of current LVADs . IM can be used to establish real-world LS group and OPCs for future single armed MCS trials.

Purpose To analyze the clinical characteristics and outcomes of patients who were bridged with ECMO to durable mechanical circulatory support (dMCS). Methods Adult patients who received dMCS between Jan 2008 and Dec 2017, registered in INTERMACS were included. Baseline characteristics, outcomes, risk factors and adverse events were analyzed in patients supported by ECMO (ECMO group) prior to dMCS implantation, and compared with INTERMACS profile 1 patients not supported by ECMO (non-ECMO group). Results Patients bridged to dMCS on ECMO were younger, more likely to have acute heart failure, ischemic etiology, and a bridge to candidacy implantation compared to other INTERMACS profile 1 patients (Table 1). Patients who received dMCS on ECMO had 1, 6, and 12 month survival of 83.8%, 71.2%, and 66.1%, inferior to non-ECMO group patients (91.4% 81.7% and 75.4%, p Conclusion Patients bridged by ECMO to dMCS have lower survival compared with other INTERMACS profile 1 patients. Older age and longer duration of HF are associated with worse outcomes. ECMO implantation was independently associated with poorer outcome.

Purpose Extra-corporeal membrane oxygenation (ECMO) as bridge to ventricular assist device (EB-VAD) therapy is frequently used for initial resuscitation of critically ill pediatric patients (INTERMACS 1 & 2). Data regarding outcomes with this strategy is limited. Methods INTERMACS 1 & 2 patients enrolled in Pediatric Interagency Registry for Mechanical Circulatory Support (PEDIMACS) between September 19th, 2012 & December 31st, 2017 constituted the study group. Of 370 patients, 271 received primary VAD (P-VAD) implantation & EB-VAD was utilized in 99 patients. Patient characteristics, durable VAD outcomes & time to first adverse event with & without preoperative ECMO bridge were compared. Sub-analysis of INTERMACS 1 patients was conducted. Results Lower age (p=0.0001) & critical cardiogenic shock(p tube feeding , mechanical ventilation & paralytics (p Conclusion In INTERMACS 1 & 2 patients EB-VAD strategy is associated with poor early & late post-implant survival. Within INTERMACS 1 early survival is comparable with both strategies. EB-VAD could potentially benefit high risk INTERMACS 1 patients