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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Hypertension: An Important But Reversible Cause of Systolic Dysfunction in a Cohort of Pediatric Patients.

Cardiac dysfunction due to hypertension (CDHTN) in pediatrics is not well described. We aimed to describe the presentation and outcomes of pediatric CDHTN and identify clinical features associated with resolution of dysfunction. A single-center retrospective cohort study of patients ≤ 21 years with CDHTN from January 2005-September 2020 was performed. Patients with systolic dysfunction without another cause, blood pressure > 95th percentile, and physician judgment that dysfunction was secondary to hypertension were included. Demographics, clinical characteristics, echocardiographic findings, and outcomes were examined using Fisher's exact and Mann-Whitney U tests. Multiple correspondence analysis was used to explore the relationship of resolution of dysfunction to clinical features. Thirty-four patients were analyzed at a median age of 10.9 (IQR 0.3-16.9) years. Patients were divided into groups < 1 year (n = 12) and ≥ 1 year (n = 22). Causes of hypertension were varied by age, with renovascular disease most common in infants (42%) and medical renal disease most common in older patients (77%). Echocardiography demonstrated mild LV dilation (median LV end-diastolic z-score 2.6) and mild LV hypertrophy (median LV mass z-score 2.4). Most patients (81%) had resolution of dysfunction, particularly infants (92%). One patient died and one patient was listed for heart transplant. None required mechanical circulatory support (MCS). No clinical features were statistically associated with resolution of dysfunction. Hypertension is an important but reversible cause of systolic dysfunction in children. Patients are likely to recover with low mortality and low utilization of MCS or transplantation. Further studies are needed to confirm features associated with resolution of dysfunction.

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.

Echocardiographic image collection and evaluation in infants with CHD: lessons learned from the imaging core lab for the Residual Lesion Score study.

Many factors affect patient outcome after congenital heart surgery, including the complexity of the heart disease, pre-operative status, patient specific factors (prematurity, nutritional status and/or presence of comorbid conditions or genetic syndromes), and post-operative residual lesions. The Residual Lesion Score is a novel tool for assessing whether specific residual cardiac lesions after surgery have a measurable impact on outcome. The goal is to understand which residual lesions can be tolerated and which should be addressed prior to leaving the operating room. The Residual Lesion Score study is a large multicentre prospective study designed to evaluate the association of Residual Lesion Score to outcomes in infants undergoing surgery for CHD. This Pediatric Heart Network and National Heart, Lung, and Blood Institute-funded study prospectively enrolled 1,149 infants undergoing 5 different congenital cardiac surgical repairs at 17 surgical centres. Given the contribution of echocardiographic measurements in assigning the Residual Lesion Score, the Residual Lesion Score study made use of a centralised core lab in addition to site review of all data. The data collection plan was designed with the added goal of collecting image quality information in a way that would permit us to improve our understanding of the reproducibility, variability, and feasibility of the echocardiographic measurements being made. There were significant challenges along the way, including the coordination, de-identification, storage, and interpretation of very large quantities of imaging data. This necessitated the development of new infrastructure and technology, as well as use of novel statistical methods. The study was successfully completed, but the size and complexity of the population being studied and the data being extracted required more technologic and human resources than expected which impacted the length and cost of conducting the study. This paper outlines the process of designing and executing this complex protocol, some of the barriers to implementation and lessons to be considered in the design of future studies.

THE MANAGEMENT OF LYMPHOPROLIFERATIVE NEOPLASIA IN FOUR NORTHERN SEA OTTERS (ENHYDRA LUTRIS KENYONI).

Lymphoproliferative neoplasia has been reported in both free-ranging sea otters and those in managed care, but little information is available on the management of this neoplastic disease in this species. This case series describes clinical lymphoma in four northern sea otters (Enhydra lutris kenyoni) in managed care. Two otters presented with Stage 5 lymphoma with evidence of hematologic spread resulting in leukemia. Two additional otters presented with Stage 3 disease. Immunophenotypes in these cases included disseminated large B-cell lymphoma and lymphoblastic lymphoma of potential T-cell origin. Cases were managed with multiagent chemotherapy protocols including prednisone, L-asparaginase, cyclophosphamide, vincristine, cytosine arabinoside, lomustine, and doxorubicin. Unique approaches included the use of a vascular access port in one case and development of an autologous vaccine in another. Survival time ranged from 81 to 409 days. Diagnosis, staging, and treatment with multiagent protocols is recommended for the management of lymphoma in sea otters.

Reduced incidence of cardiac rejection in multi-organ transplants: A propensity matched study.

BACKGROUND: Rejection remains a primary cause of graft loss after heart transplant (HT). Recognizing the immunomodulation of multi-organ transplant can enhance our understanding of the mechanisms of cardiac rejection. METHODS: This retrospective cohort study identified patients from the UNOS database with isolated heart (H, N = 37 433), heart-kidney (HKi, N = 1516), heart-liver (HLi, N = 286), and heart-lung (HLu, N = 408) transplants from 2004 to 2019. Propensity score matching reduced baseline differences between groups. Outcomes included risk of rejection prior to transplant hospital discharge and within 1 year, and mortality within 1 year of transplant. RESULTS: In the propensity score matched data, the relative risk of being treated for rejection prior to transplant hospital discharge was 61% lower for HKi (RR .39, 95% CI .29, .53) and 87% lower for HLi (RR .13, 95% CI .05, .37) compared to H. Similarly, the probability of being treated for rejection in the first year after transplant remained lower in HKi (RR .45, 95% CI .35, .57) and HLi (RR .13, 95% CI .06, .28) compared to H. The 1-year survival analysis revealed an equivalent risk of death in HKi (HR .84, 95% CI .68, 1.03) and HLi (HR 1.41, 95% CI .83, 2.41) compared to H, while HLu had a higher risk of death in the first year after transplant (HR 1.65, 95% CI 1.17, 2.33). CONCLUSIONS: Recipients of HKi and HLi experience a reduced risk of rejection when compared to H, but an equivalent risk of 1 yr mortality. These findings have important implications for the future of HT medicine.

Left bundle branch area pacing in congenital heart disease.

AIMS: Left bundle branch area pacing (LBBAP) has been shown to be effective and safe. Limited data are available on LBBAP in the congenital heart disease (CHD) population. This study aims to describe the feasibility and safety of LBBAP in CHD patients compared with non-CHD patients. METHODS AND RESULTS: This is a single-centre, non-randomized observational study recruiting consecutive patients with bradycardia indication. Demographic data, ECGs, imaging, and procedural data including lead parameters were recorded. A total of 39 patients were included: CHD group (n = 13) and non-CHD group (n = 26). Congenital heart disease patients were younger (55 ± 14.5 years vs. 73.2 ± 13.1, P < 0.001). Acute success was achieved in all CHD patients and 96% (25/26) of non-CHD patients. No complications were encountered in either group. The procedural time for CHD patients was comparable (96.4 ± 54 vs. 82.1 ± 37.9 min, P = 0.356). Sheath reshaping was required in 7 of 13 CHD patients but only in 1 of 26 non-CHD patients, reflecting the complex and distorted anatomy of the patients in this group. Lead parameters were similar in both groups; R wave (11 ± 7 mV vs. 11.5 ± 7.5, P = 0.881) and pacing threshold (0.6 ± 0.3 V vs. 0.7 ± 0.3, P = 0.392). Baseline QRS duration was longer in the CHD group (150 ± 28.2 vs. 118.6 ± 26.6 ms, P = 0.002). Despite a numerically greater reduction in QRS and a similar left ventricular activation time (65.9 ± 6.2 vs. 67 ± 16.8 ms, P = 0.840), the QRS remained longer in the CHD group (135.5 ± 22.4 vs. 106.9 ± 24.7 ms, P = 0.005). CONCLUSION: Left bundle branch area pacing is feasible and safe in CHD patients as compared to that in non-CHD patients. Procedural and fluoroscopy times did not differ between both groups. Lead parameters were satisfactory and stable over a short-term follow-up.

Anatomic, histologic, and mechanical features of the right atrium: implications for leadless atrial pacemaker implantation.

BACKGROUND: Leadless pacemakers (LPs) may mitigate the risk of lead failure and pocket infection related to conventional transvenous pacemakers. Atrial LPs are currently being investigated. However, the optimal and safest implant site is not known. OBJECTIVES: We aimed to evaluate the right atrial (RA) anatomy and the adjacent structures using complementary analytic models [gross anatomy, cardiac magnetic resonance imaging (MRI), and computer simulation], to identify the optimal safest location to implant an atrial LP human. METHODS AND RESULTS: Wall thickness and anatomic relationships of the RA were studied in 45 formalin-preserved human hearts. In vivo RA anatomy was assessed in 100 cardiac MRI scans. Finally, 3D collision modelling was undertaken assessing for mechanical device interaction. Three potential locations for an atrial LP were identified; the right atrial appendage (RAA) base, apex, and RA lateral wall. The RAA base had a wall thickness of 2.7 ± 1.6 mm, with a low incidence of collision in virtual implants. The anteromedial recess of the RAA apex had a wall thickness of only 1.3 ± 0.4 mm and minimal interaction in the collision modelling. The RA lateral wall thickness was 2.6 ± 0.9 mm but is in close proximity to the phrenic nerve and sinoatrial artery. CONCLUSIONS: Based on anatomical review and 3D modelling, the best compromise for an atrial LP implantation may be the RAA base (low incidence of collision, relatively thick myocardial tissue, and without proximity to relevant epicardial structures); the anteromedial recess of the RAA apex and lateral wall are alternate sites. The mid-RAA, RA/superior vena cava junction, and septum appear to be sub-optimal fixation locations.

High-power chargers for electric vehicles: are they safe for patients with pacemakers and defibrillators?

AIMS: Battery electric vehicle (BEV) sales and use are rapidly expanding. Battery electric vehicles, along with their charging stations, are a potential source of electromagnetic interference (EMI) for patients with cardiac implantable electronic devices (CIEDs). The new 'high-power' charging stations have the potential to create strong electromagnetic fields and induce EMI in CIEDs, and their safety has not been evaluated. METHODS AND RESULTS: A total of 130 CIED patients performed 561 charges of four BEVs and a test vehicle (350 kW charge capacity) using high-power charging stations under continuous 6-lead electrocardiogram monitoring. The charging cable was placed directly over the CIED, and devices were programmed to maximize the chance of EMI detection. Cardiac implantable electronic devices were re-interrogated after patients charged all BEVs and the test vehicle for evidence of EMI. There were no incidences of EMI, specifically no over-sensing, pacing inhibition, inappropriate tachycardia detection, mode switching, or spontaneous reprogramming. The risk of EMI on a patient-based analysis is 0/130 [95% confidence interval (CI) 0%-2%], and the risk of EMI on a charge-based analysis is 0/561 (95% CI 0%-0.6%). The effective magnetic field along the charging cable was 38.65 µT and at the charging station was 77.9 µT. CONCLUSIONS: The use of electric cars with high-power chargers by patients with cardiac devices appears to be safe with no evidence of clinically relevant EMI. Reasonable caution, by minimizing the time spent in close proximity with the charging cables, is still advised as the occurrence of very rare events cannot be excluded from our results.

Temporal trends in primary payers in pediatric heart transplant and association with long-term survival.

BACKGROUND: Pediatric heart transplantation (HT) is resource intensive. In adults, there has been an increase in the proportion of HTs funded by public insurance, with post-HT outcomes inferior to those funded by private sources. Trends in the funding of pediatric HT and outcomes in children have not been described. METHODS: We queried the United Network for Organ Sharing (UNOS) database for children (<18 years) listed for and undergoing HT between 2004 and 2021. We identified the primary payer at listing, HT, 1 year, and 1-5 years following HT. Trends were analyzed using generalized logit models. Multivariable-extended Cox regression models were used to test the relationship between insurance type at the time of transplant and time to death or re-transplant. RESULTS: There were 6382 pediatric patients who underwent transplants and had either public or private insurance at the time of transplant. The percentage of patients with public insurance at the time of HT increased over time. Public insurance at the time of HT was associated with an increased risk of death or re-transplant beyond 2 months after HT (adjusted HR at 6 months = 1.43, 95% CI: 1.13-1.81, p = .003; adjusted HR at 9 months = 1.67, 95% CI: 1.17-2.37, p = .004). CONCLUSION: There has been a statistically significant trend toward increasing public insurance for children awaiting, at the time of, and after HT. Black patients and those with public insurance at HT have worse long-term outcomes. This study highlights ongoing disparities in pediatric HT and the need to focus efforts on achieving equitable outcomes.

Fontan-associated liver disease after heart transplant.

BACKGROUND: Fontan associated liver disease (FALD) potentially impacts Fontan patients undergoing heart transplant. This multi-center study sought to identify pre-transplant risk factors and characterize any post-transplant liver recovery in those patients undergoing heart-alone transplant. METHODS: Review of Fontan patients at 12 pediatric institutions who underwent heart transplant between 2001-2019. Radiologists reviewed pre and post-transplant liver imaging for fibrosis. Laboratory, pathology and endoscopy studies were reviewed. RESULTS: 156 patients underwent transplant due to decreased ventricular function (49%), protein losing enteropathy (31%) or plastic bronchitis (10%); median age at transplant was 13.6 years (interquartile range IQR 7.8, 17.2) with a median of 9.3 years (IQR 3.2, 13.4) between the Fontan operation and transplant. Few patients had pre-transplant endoscopy (18%), and liver biopsy (19%). There were 31 deaths (20%). The median time from transplant to death was 0.5 years (95% Confidence Interval CI 0.0, 3.6). The five-year survival was 73% (95% CI 64%, 83%). Deaths were related to cardiac causes in 68% (21/31) and infection in 6 (19%). A pre-transplant elevation in bilirubin was a predictor of death. Higher platelet levels were protective. Immediate post-transplant elevations in creatinine, AST, ALT, and INR were predictive of death. Advanced liver fibrosis identified on ultrasound, computed tomography, or magnetic resonance imaging was not predictive of death. Liver imaging suggested some improvement in liver congestion post-transplant. CONCLUSIONS: Elevated bilirubin, but not fibrosis on liver imaging, was associated with post-heart transplant mortality in Fontan patients in this multicenter retrospective study. Additionally, heart transplant may alter the progression of FALD.

Outcomes after initial heart failure consultation in Fontan patients.

BACKGROUND: Patients with Fontan failure are high-risk candidates for heart transplantation and other advanced therapies. Understanding the outcomes following initial heart failure consultation can help define appropriate timing of referral for advanced heart failure care. METHODS: This is a survey study of heart failure providers seeing any Fontan patient for initial heart failure care. Part 1 of the survey captured data on clinical characteristics at the time of heart failure consultation, and Part 2, completed 30 days later, captured outcomes (death, transplant evaluation outcome, and other interventions). Patients were classified as "too late" (death or declined for transplant due to being too sick) and/or "care escalation" (ventricular assist device implanted, inotrope initiated, and/or listed for transplant), within 30 days. "Late referral" was defined as those referred too late and/or had care escalation. RESULTS: Between 7/2020 and 7/2022, 77 Fontan patients (52% inpatient) had an initial heart failure consultation. Ten per cent were referred too late (6 were too sick for heart transplantation with one subsequent death, and two others died without heart transplantation evaluation, within 30 days), and 36% had care escalation (21 listed ± 5 ventricular assist device implanted ± 6 inotrope initiated). Overall, 42% were late referrals. Heart failure consultation < 1 year after Fontan surgery was strongly associated with late referral (OR 6.2, 95% CI 1.8-21.5, p=0.004). CONCLUSIONS: Over 40% of Fontan patients seen for an initial heart failure consultation were late referrals, with 10% dying or being declined for transplant within a month of consultation. Earlier referral, particularly for those with heart failure soon after Fontan surgery, should be encouraged.

CAUSES OF MORTALITY AND COMORBIDITIES IN CAIMAN LIZARDS (DRACAENA GUIANENSIS) AT SIX ZOOLOGICAL INSTITUTIONS.

An understanding of the main causes of mortality in caiman lizards (Dracaena guianensis) under managed care is imperative to promote optimal husbandry, health, and welfare. A retrospective review of morbidity and mortality in caiman lizards from North American zoological institutions between 2005 and 2020 was conducted. Postmortem data, including gross necropsy and histopathology findings, were available for 32 caiman lizards (n = 12 subadults, n = 20 adults) from six zoological institutions. Necropsy reports were evaluated to collect general demographic data, categorize cause of death (accident/trauma, congenital/genetic, degenerative/geriatric, infectious, deposition disease, neoplastic, unknown, and multifactorial), and assess common comorbidities. Infectious disease was the most common cause of mortality in adult lizards (8/20; 40%) with amoebiasis and bacterial etiologies being overrepresented. Demise due to traumatic/accidental injury was the second most common cause of death in adult lizards (3/20;15%) and included blunt force trauma or suspected drowning. Infectious disease (4/12; 33.3%) and trauma/accidental injury (4/12; 33.3%) were also the most common causes of death in subadults. The most common comorbidities or other incidental findings identified during necropsy included trematode parasitism (15/32; 46.9%), arteriosclerosis (11/32; 34.4%), and adrenocortical hyperplasia (6/32; 18.8%). This retrospective review suggests that management practices to prevent and control infectious diseases and mitigate traumatic injury play a pivotal role in the long-term care and survival of caiman lizards in managed care.

mRNA Coronavirus Disease 2019 Vaccine-Associated Myopericarditis in Adolescents: A Survey Study.

In this survey study of institutions across the US, marked variability in evaluation, treatment, and follow-up of adolescents 12 through 18 years of age with mRNA coronavirus disease 2019 (COVID-19) vaccine-associated myopericarditis was noted. Only one adolescent with life-threatening complications was reported, with no deaths at any of the participating institutions.

MYH7 variants cause complex congenital heart disease.

MYH7, encoding the myosin heavy chain sarcomeric ß-myosin heavy chain, is a common cause of both hypertrophic and dilated cardiomyopathy. Additionally, families with left ventricular noncompaction cardiomyopathy (LVNC) and congenital heart disease (CHD), typically septal defects or Ebstein anomaly, have been identified to have heterozygous pathogenic variants in MHY7. One previous case of single ventricle CHD with heart failure due to a MYH7 variant has been identified. Herein, we present a single center's experience of complex CHD due to MYH7 variants. Three probands with a history of CHD, LVNC, and/or arrhythmias were identified to have MYH7 variants through multigene panel testing or exome sequencing. These three patients collectively had 12 affected family members, four with a history of Ebstein anomaly and seven with a history of LVNC. These findings suggest a wider phenotypic spectrum in MYH7-related CHD than previously understood. Further investigation into the possible role of MYH7 in CHD and mechanism of disease is necessary to fully delineate the phenotypic spectrum of MYH7-related cardiac disease. MYH7 should be considered for families with multiple individuals with complex CHD in the setting of a family history of LVNC or arrhythmias.

COVID-19 vaccination in children and adolescents aged 5 years and older undergoing treatment for cancer and non-malignant haematological conditions: Australian and New Zealand Children's Haematology/Oncology Group consensus statement.

INTRODUCTION: The Australian Technical Advisory Group on Immunisation and New Zealand Ministry of Health recommend all children aged ≥ 5 years receive either of the two mRNA COVID-19 vaccines: Comirnaty (Pfizer), available in both Australia and New Zealand, or Spikevax (Moderna), available in Australia only. Both vaccines are efficacious and safe in the general population, including children. Children and adolescents undergoing treatment for cancer and immunosuppressive therapy for non-malignant haematological conditions are particularly vulnerable, with an increased risk of severe or fatal COVID-19. There remains a paucity of data regarding the immune response to COVID-19 vaccines in immunosuppressed paediatric populations, with data suggestive of reduced immunogenicity of the vaccine in immunocompromised adults. RECOMMENDATIONS: Considering the safety profile of mRNA COVID-19 vaccines and the increased risk of severe COVID-19 in immunocompromised children and adolescents, COVID-19 vaccination is strongly recommended for this at-risk population. We provide a number of recommendations regarding COVID-19 vaccination in this population where immunosuppressive, chemotherapeutic and/or targeted biological agents are used. These include the timing of vaccination in patients undergoing active treatment, management of specific situations where vaccination is contraindicated or recommended under special precautions, and additional vaccination recommendations for severely immunocompromised patients. Finally, we stress the importance of upcoming clinical trials to identify the safest and most efficacious vaccination regimen for this population. CHANGES IN MANAGEMENT AS A RESULT OF THIS STATEMENT: This consensus statement provides recommendations for COVID-19 vaccination in children and adolescents aged ≥ 5 years with cancer and immunocompromising non-malignant haematological conditions, based on evidence, national and international guidelines and expert opinion. ENDORSED BY: The Australian and New Zealand Children's Haematology/Oncology Group.

Patient and Device Selection in Pediatric MCS: A Review of Current Consensus and Unsettled Questions.

The field of pediatric ventricular assist device (VAD) support has expanded significantly over the past 20 years, with one third of pediatric heart transplant recipients currently being bridged to transplant with a VAD. Despite increased pediatric VAD utilization, however, there remains little formalized guidance for patient or device selection. The population of children with advanced heart failure is quite heterogeneous, and the available data suggest that VAD outcomes vary significantly based upon patient size, anatomy, level of illness, and type of device implanted. In an effort to better understand current practice patterns and identify populations for whom there does not appear to be a consensus approach to achieving optimal VAD outcomes, the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) has surveyed clinical decision-making among member sites and conducted a review of the available literature regarding patient population-specific VAD outcomes and center-specific practices related to patient and device selection. Rather than aiming to provide clinical guidelines, this document offers an overview of contemporary approaches to patient and device selection, highlighting specific populations for whom there is not a consensus approach to achieving reliably good VAD outcomes, as these populations may benefit most from future research and quality improvement efforts directed toward identifying best practice.

Center Variation in Indication and Short-Term Outcomes after Pediatric Heart Transplantation: Analysis of a Merged United Network for Organ Sharing - Pediatric Health Information System Cohort.

The relationship between center-specific variation in indication for pediatric heart transplantation and short-term outcomes after heart transplantation is not well described. We used merged patient- and hospital-level data from the United Network for Organ Sharing and the Pediatric Health Information Systems to analyze outcomes according to transplant indication for a cohort of children (≤ 21 years old) who underwent heart transplantation between 2004 and 2015. Outcomes included 30-day mortality, transplant hospital admission mortality, and hospital length of stay, with multivariable adjustment performed according to patient and center characteristics. The merged cohort reflected 2169 heart transplants at 20 U.S. centers. The median number of transplants annually at each center was 11.6, but ranged from 3.5 to 22.6 transplants/year. Congenital heart disease was the indication in the plurality of cases (49.2%), with cardiomyopathy (46%) and myocarditis (4.8%) accounting for the remainder. There was significant center-to-center variability in congenital heart disease as the principal indication, ranging from 15% to 66% (P < 0.0001). After adjustment, neither center volume nor proportion of indications for transplantation were associated with 30-day or transplant hospital admission mortality. In this large, merged pediatric cohort, variation was observed at center level in annual transplant volume and prevalence of indications for heart transplantation. Despite this variability, center volume and proportion of indications represented at a given center did not appear to impact short-term outcomes.

Safety and Feasibility of Exercise Rehabilitation in Children with Ventricular Assist Devices.

Children with advanced heart failure may require ventricular assist devices (VAD) while awaiting heart transplantation. Currently, no data exist regarding the safety of exercise rehabilitation (ER) in children on VAD support. The purpose of this study was to determine the safety and feasibility of ER in children on VAD support awaiting heart transplantation. Eligible patients underwent VAD placement between 1998 and 2019; both inpatient and outpatient participants were included. After VAD implantation and when ambulatory, patients were enrolled in ER. Exercise sessions were scheduled three times a week and consisted of aerobic and musculoskeletal conditioning. A total of 29 patients (59% male, mean age 14 ± 3.2 years) were included with a median VAD duration of 120 ± 109 days. Cardiac diagnoses included cardiomyopathy (81%) and congenital heart disease (19%). VAD type included pulsatile (59%) and continuous-flow devices (41%). Eight hundred and sixty-four (85%) ER sessions were successfully completed and began at a mean of 49 days (range 19-108) after VAD implant. No adverse events, including episodes of hypotension, significant complex arrhythmia, or VAD malfunction occurred during exercise testing or ER, and no sessions were discontinued prematurely. Pediatric patients on VAD support can safely participate in ER with relatively high compliance, and sessions can be implemented early after VAD implantation. Given the safety profile, ER in pediatric VAD recipients, which is a modifiable pre-transplant risk factor that may improve functional capacity, warrants further study as a potential modality to improve post-transplant outcomes.

Current Practices in Treating Cardiomyopathy and Heart Failure in Duchenne Muscular Dystrophy (DMD): Understanding Care Practices in Order to Optimize DMD Heart Failure Through ACTION.

Cardiac disease has emerged as a leading cause of mortality in Duchenne muscular dystrophy in the current era. This survey sought to identify the diagnostic and therapeutic approach to DMD among pediatric cardiologists in Advanced Cardiac Therapies Improving Outcomes Network. Pediatric cardiology providers within ACTION (a multi-center pediatric heart failure learning network) were surveyed regarding their approaches to cardiac care in DMD. Thirty-one providers from 23 centers responded. Cardiac MRI and Holter monitoring are routinely obtained, but the frequency of use and indications for ordering these tests varied widely. Angiotensin converting enzyme inhibitor and aldosterone antagonist are generally initiated prior to onset of systolic dysfunction, while the indications for initiating beta-blocker therapy vary more widely. Seventeen (55%) providers report their center has placed an implantable cardioverter defibrillator in at least 1 DMD patient, while 11 providers (35%) would not place an ICD for primary prevention in a DMD patient. Twenty-three providers (74%) would consider placement of a ventricular assist device (VAD) as destination therapy (n = 23, 74%) and three providers (10%) would consider a VAD only as bridge to transplant. Five providers (16%) would not consider VAD at their institution. Cardiac diagnostic and therapeutic approaches vary among ACTION centers, with notable variation present regarding the use of advanced therapies (ICD and VAD). The network is currently working to harmonize medical practices and optimize clinical care in an era of rapidly evolving outcomes and cardiac/skeletal muscle therapies.