Cardiac atrial pathology in Duchenne muscular dystrophy

INTRODUCTION/AIMS

Duchenne muscular dystrophy (DMD) is characterized by fibrofatty replacement of muscle. This has been documented in the ventricular myocardium of DMD patients, but there is limited description of atrial involvement. The purpose of this study is to examine the arrhythmia and ectopy burden in patients with DMD and non-DMD dilated cardiomyopathy (DCM) and to characterize the cardiac histopathologic changes in DMD patients across the disease spectrum.

METHODS

This was a retrospective analysis of age-matched patients with DMD and non-DMD DCM who received a Holter monitor and cardiac imaging within 100 days of each other between 2010 and 2020. Twenty-four-hour Holter monitors were classified based on the most recent left ventricular ejection fraction at the time of monitoring. Cardiac histopathologic specimens from whole-heart examinations at the time of autopsy from three DMD patients and one DCM patient were reviewed.

RESULTS

A total of 367 patients with 1299 Holter monitor recordings were included over the study period, with 94% representing DMD patients and 6% non-DMD DCM. Patients with DMD had more atrial ectopy across the cardiac function spectrum (p < 0.05). There was no difference in ventricular ectopy. Four DMD patients developed symptomatic atrial arrhythmias. Autopsy specimens from DMD patients demonstrated fibrofatty infiltration of both atrial and ventricular myocardium.

DISCUSSION

The atrial myocardium in patients with DMD is unique. Autopsy specimens reveal fibofatty replacement of the atrial myocardium, which may be a nidus for both ectopy and arrhythmias in DMD patients.

Differences in life expectancy within and between countries: implications for domestic TAVI guidelines in Australia and Aotearoa New Zealand

The advent of transcatheter aortic valve implantation (TAVI) has caused a paradigm shift in the management of aortic stenosis away from traditional surgical aortic valve replacement (SAVR). However, uncertainty remains about the long-term (>10 year) durability of TAVI valves, especially in younger patients. This viewpoint collates life expectancy data from Australia and Aotearoa New Zealand to propose sex-specific age-based recommendations for choice of SAVR versus TAVI in their respective general populations and among Aboriginal and Torres Strait Islander people in Australia and both Māori and Pacific peoples living in Aotearoa New Zealand.

Role of CAMK2D in neurodevelopment and associated conditions

The calcium/calmodulin-dependent protein kinase type 2 (CAMK2) family consists of four different isozymes, encoded by four different genes-CAMK2A, CAMK2B, CAMK2G, and CAMK2D-of which the first three have been associated recently with neurodevelopmental disorders. CAMK2D is one of the major CAMK2 proteins expressed in the heart and has been associated with cardiac anomalies. Although this CAMK2 isoform is also known to be one of the major CAMK2 subtypes expressed during early brain development, it has never been linked with neurodevelopmental disorders until now. Here we show that CAMK2D plays an important role in neurodevelopment not only in mice but also in humans. We identified eight individuals harboring heterozygous variants in CAMK2D who display symptoms of intellectual disability, delayed speech, behavioral problems, and dilated cardiomyopathy. The majority of the variants tested lead to a gain of function (GoF), which appears to cause both neurological problems and dilated cardiomyopathy. In contrast, loss-of-function (LoF) variants appear to induce only neurological symptoms. Together, we describe a cohort of individuals with neurodevelopmental disorders and cardiac anomalies, harboring pathogenic variants in CAMK2D, confirming an important role for the CAMK2D isozyme in both heart and brain function.

Advancing the care of individuals with cancer through innovation & technology: Proceedings from the cardiology oncology innovation summit 2020 and 2021

As cancer therapies increase in effectiveness and patients' life expectancies improve, balancing oncologic efficacy while reducing acute and long-term cardiovascular toxicities has become of paramount importance. To address this pressing need, the Cardiology Oncology Innovation Network (COIN) was formed to bring together domain experts with the overarching goal of collaboratively investigating, applying, and educating widely on various forms of innovation to improve the quality of life and cardiovascular healthcare of patients undergoing and surviving cancer therapies. The COIN mission pillars of innovation, collaboration, and education have been implemented with cross-collaboration among academic institutions, private and public establishments, and industry and technology companies. In this report, we summarize proceedings from the first two annual COIN summits (inaugural in 2020 and subsequent in 2021) including educational sessions on technological innovations for establishing best practices and aligning resources. Herein, we highlight emerging areas for innovation and defining unmet needs to further improve the outcome for cancer patients and survivors of all ages. Additionally, we provide actionable suggestions for advancing innovation, collaboration, and education in cardio-oncology in the digital era.

Use of volumetric absorptive microsampling and parallel reaction monitoring mass spectrometry for tacrolimus blood trough measurements at home in pediatric heart transplant patients

Background

Measurement of trough levels for calcineurin inhibitors by venipuncture sampling is a mainstay of patient management in solid organ transplant recipients but challenging in pediatric patients. Volumetric Absorptive Microsampling (VAMS) is a patient-friendly, minimally invasive sampling technique to accurately collect blood. An assay for measurement of tacrolimus in blood using VAMS, coupled with parallel reaction monitoring (PRM) mass spectrometry, was validated in pediatric heart transplant patients.

Methods

Tacrolimus was measured by a newly developed high-resolution PRM assay and compared with low-resolution tandem mass spectrometry (MRM). Dried blood samples were collected from pediatric heart transplant patients (n = 35) using VAMS devices and a satisfaction survey was completed by patients/guardians. Tacrolimus concentrations were compared across whole liquid blood, dried blood spots, and capillary blood, and shipping stability determined.

Results

The PRM assay was linear over a range 1-50 ng/mL, similar to MRM but had greater specificity due to reduced background noise. No significant differences in tacrolimus concentrations were observed between VAMS and venous blood. Tacrolimus dried on VAM tips was stable for 14 days and concentrations were unaffected by postal shipping. The variability in two simultaneously collected at-home patient samples was minimal - average concentration difference was 0.12 ± 0.94 ng/mL (p = 0.6) between paired samples.

Conclusion

A high resolution PRM mass spectrometry assay was developed for home-based dried blood collections for therapeutic monitoring of tacrolimus. The advantage of PRM was enhanced specificity and the VAMS devices provided a simple and convenient approach to blood sampling at home in pediatric heart transplant patients.

Balloon atrial septostomy versus left atrial cannulation for left heart decompression in children with dilated cardiomyopathy and myocarditis on extracorporeal membrane oxygenation: An ELSO registry analysis

INTRODUCTION

In children with myocarditis or dilated cardiomyopathy (DCM) on extracorporeal membrane oxygenation (ECMO) for cardiogenic shock, it is often necessary to decompress the left heart to minimize distension and promote myocardial recovery. We compare outcomes in those who underwent balloon atrial septostomy (BAS) versus direct left atrial (LA) drainage for left heart decompression in this population.

METHODS

Retrospective study of the Extracorporeal Life Support Organization (ELSO) multicenter registry of patients ≤ 18 years with myocarditis or DCM on ECMO who underwent LA decompression. Descriptive and univariate statistics assessed association of patient factors with decompression type. Multivariable logistic regression sought independent associations with outcomes.

RESULTS

369 pediatric ECMO runs were identified. 52% myocarditis, 48% DCM, overall survival 74%. 65% underwent BAS and 35% LA drainage. Patient demographics including age, weight, gender, race/ethnicity, diagnosis, pre-ECMO pH, mean airway pressure, and arrest status were similar. 89% in the BAS group were peripherally cannulated onto ECMO, versus 3% in the LA drainage group (p < .001). On multivariable analysis, LA drainage (OR 3.96; 95% CI, 1.47-10.711; p = .007), renal complication (OR 2.37; 95% CI, 1.41-4.01; p = .001), cardiac complication (OR 3.14; 95% CI, 1.70-5.82; p < .001), and non-white race/ethnicity (OR 1.75; 95% CI, 1.04-2.94; p = .035) were associated with greater odds of mortality. There was a trend toward more episodes of pulmonary hemorrhage in BAS (n = 17) versus LA drainage group (n = 3), p = .08. Comparing only those with central cannulation, LA drainage group was more likely to be discontinued from ECMO due to recovery (72%) versus the BAS group (48%), p = .032.

CONCLUSIONS

In children with myocarditis or DCM, there was a three times greater likelihood for mortality with LA drainage versus BAS for LA decompression. When adjusted for central cannulation groups only, there was better recovery in the LA drainage group and no difference in mortality. Further prospective evaluation is warranted.

Left Ventricular Systolic Dysfunction in Patients Diagnosed With Hypertrophic Cardiomyopathy During Childhood: Insights From the SHaRe Registry

BACKGROUND

The development of left ventricular systolic dysfunction (LVSD) in hypertrophic cardiomyopathy (HCM) is rare but serious and associated with poor outcomes in adults. Little is known about the prevalence, predictors, and prognosis of LVSD in patients diagnosed with HCM as children.

METHODS

Data from patients with HCM in the international, multicenter SHaRe (Sarcomeric Human Cardiomyopathy Registry) were analyzed. LVSD was defined as left ventricular ejection fraction <50% on echocardiographic reports. Prognosis was assessed by a composite of death, cardiac transplantation, and left ventricular assist device implantation. Predictors of developing incident LVSD and subsequent prognosis with LVSD were assessed using Cox proportional hazards models.

RESULTS

We studied 1010 patients diagnosed with HCM during childhood (<18 years of age) and compared them with 6741 patients with HCM diagnosed as adults. In the pediatric HCM cohort, median age at HCM diagnosis was 12.7 years (interquartile range, 8.0-15.3), and 393 (36%) patients were female. At initial SHaRe site evaluation, 56 (5.5%) patients with childhood-diagnosed HCM had prevalent LVSD, and 92 (9.1%) developed incident LVSD during a median follow-up of 5.5 years. Overall LVSD prevalence was 14.7% compared with 8.7% in patients with adult-diagnosed HCM. Median age at incident LVSD was 32.6 years (interquartile range, 21.3-41.6) for the pediatric cohort and 57.2 years (interquartile range, 47.3-66.5) for the adult cohort. Predictors of developing incident LVSD in childhood-diagnosed HCM included age <12 years at HCM diagnosis (hazard ratio [HR], 1.72 [CI, 1.13-2.62), male sex (HR, 3.1 [CI, 1.88-5.2), carrying a pathogenic sarcomere variant (HR, 2.19 [CI, 1.08-4.4]), previous septal reduction therapy (HR, 2.34 [CI, 1.42-3.9]), and lower initial left ventricular ejection fraction (HR, 1.53 [CI, 1.38-1.69] per 5% decrease). Forty percent of patients with LVSD and HCM diagnosed during childhood met the composite outcome, with higher rates in female participants (HR, 2.60 [CI, 1.41-4.78]) and patients with a left ventricular ejection fraction <35% (HR, 3.76 [2.16-6.52]).

CONCLUSIONS

Patients with childhood-diagnosed HCM have a significantly higher lifetime risk of developing LVSD, and LVSD emerges earlier than for patients with adult-diagnosed HCM. Regardless of age at diagnosis with HCM or LVSD, the prognosis with LVSD is poor, warranting careful surveillance for LVSD, especially as children with HCM transition to adult care.

Heart-kidney listing is better than isolated heart listing for pediatric heart transplant candidates with significant renal insufficiency

OBJECTIVES

Significant renal insufficiency is identified as a risk factor for post-transplantation mortality in pediatric heart transplant recipients. This study evaluates simultaneous heart-kidney transplantation listing outcomes compared with heart transplant for pediatric candidates with significant renal insufficiency.

METHODS

The United Network for Organ Sharing registry was searched for patients (January 1987 to March 2020) who were simultaneously listed for a heart-kidney transplantation or for heart transplant with significant renal insufficiency at the time of listing. Significant renal insufficiency was defined as needing dialysis or having a low estimated glomerular filtration rate (<40 mL/min). Survival was calculated using Kaplan-Meier analysis.

RESULTS

A total of 427 cases were identified; 109 were listed for heart-kidney transplantation, and 318 were listed for heart transplant alone. Median time on the waitlist was 101 days (interquartile range, 28-238) for heart-kidney transplantation listings compared with 39 days (14-86) and 23.5 days (6-51) for heart transplant recipients with a low estimated glomerular filtration rate (P = .002) or on dialysis (P < .001), respectively. Of all heart-kidney transplantation listings, 66% (n = 71) received a transplant compared with 54% (n = 173) of heart transplantation with significant renal insufficiency (P = .005) with a mean survival of 14.6 years (12.7-16.4 years) for heart transplant without significant renal insufficiency at transplantation and 7.6 years (5.4-9.9 years) for heart transplant with significant renal insufficiency at transplantation. At 1 year after listing, 69% of heart-kidney transplantation listed recipients were alive, compared with 51% of heart transplant listed recipients (P = .029). Heart-kidney transplantation recipients had better 1-year post-transplantation survival (86%) than heart transplantation with significant renal insufficiency at transplant (66%) (P = .001). There was no significant difference in the 1- and 5-year survivals of those undergoing heart transplantation listed with significant renal insufficiency but no significant renal insufficiency at the time of transplant (89% and 78%) and heart-kidney transplantation recipients (86% and 81%; P = .436).

CONCLUSIONS

Pediatric candidates with significant renal insufficiency listed for heart-kidney transplantation have superior waitlist and post-transplantation outcomes compared with those listed for heart transplant alone. Patients with significant renal insufficiency should be listed for heart-kidney transplantation, however; if their renal function improves significantly, heart transplant alone appears judicious.

Stx4 is required to regulate cardiomyocyte Ca2+ handling during vertebrate cardiac development

Requirements for vesicle fusion within the heart remain poorly understood, despite the multitude of processes that necessitate proper intracellular trafficking within cardiomyocytes. Here, we show that Syntaxin 4 (STX4), a target-Soluble N-ethylmaleimide sensitive factor attachment receptor (t-SNARE) protein, is required for normal vertebrate cardiac conduction and vesicular transport. Two patients were identified with damaging variants in STX4. A patient with a homozygous R240W missense variant displayed biventricular dilated cardiomyopathy, ectopy, and runs of non-sustained ventricular tachycardia, sensorineural hearing loss, global developmental delay, and hypotonia, while a second patient displayed severe pleiotropic abnormalities and perinatal lethality. CRISPR/Cas9-generated stx4 mutant zebrafish exhibited defects reminiscent of these patients' clinical presentations, including linearized hearts, bradycardia, otic vesicle dysgenesis, neuronal atrophy, and touch insensitivity by 3 days post fertilization. Imaging of Vamp2+ vesicles within stx4 mutant zebrafish hearts showed reduced docking to the cardiomyocyte sarcolemma. Optical mapping of the embryonic hearts coupled with pharmacological modulation of Ca²⁺ handling together support that zebrafish stx4 mutants have a reduction in L-type Ca²⁺ channel modulation. Transgenic overexpression of zebrafish Stx4^R241W, analogous to the first patient's STX4^R240W variant, indicated that the variant is hypomorphic. Thus, these data show an in vivo requirement for SNAREs in regulating normal embryonic cardiac function and that variants in STX4 are associated with pleiotropic human disease, including cardiomyopathy.

Abnormal maximal and submaximal cardiopulmonary exercise capacity in pediatric stem cell transplant recipients despite normal standard echocardiographic parameters: a pilot study

BACKGROUND

Left ventricular systolic dysfunction is a known complication of stem cell transplant (SCT). There has been minimal research to determine if subclinical cardiac dysfunction exists in SCT patients utilizing tools other than standard echocardiography, such as maximal and submaximal effort cardiopulmonary exercise testing (CPET) and vascular function studies.

OBJECTIVE

The objective of this study was to determine the rate of subclinical cardiac dysfunction in patients with normal ejection fraction after SCT, identified by abnormal values by CPET, tissue-Doppler imaging, and arterial stiffness measurements and to further describe submaximal exercise test measures in this population.

STUDY DESIGN

A prospective cohort study of SCT survivors who were at least three years post-SCT without prior anthracycline or radiation exposure and with preserved systolic function (LV ejection fraction > 50%) was performed to evaluate for abnormalities in exercise, vascular function, and diastolic function in an effort to detect subclinical dysfunction in SCT patients.

RESULTS

There were 11 patients (12.4±3.8-years-old) included in the study. No patients had diastolic dysfunction. All patients completed a maximal effort exercise test, and 73% (8/11) had abnormal peak oxygen consumption (VO₂peak), which is a measure of aerobic fitness. However, during submaximal effort CPET, 45% (5/11) had an abnormal VO₂ at anaerobic threshold (i.e. the point in exercise where aerobic transitions to anaerobic metabolism and fatigue starts), and 64% (7/11) had an abnormal oxygen uptake efficiency slope (a measure that relates VO₂peak to total ventilation). 86% (6/7) of the patients with an abnormal oxygen uptake efficiency slope ultimately had an abnormal VO₂peak. There were no vascular function abnormalities.

CONCLUSION

Pediatric survivors of SCT often have abnormal maximal and submaximal exercise capacity without vascular or cardiac dysfunction.

Current State of Pediatric Cardio-Oncology: A Review

The landscape of pediatric oncology has dramatically changed over the course of the past several decades with five-year survival rates surpassing 80%. Anthracycline therapy has been the cornerstone of many chemotherapy regimens for pediatric patients since its introduction in the 1960s, and recent improved survival has been in large part due to advancements in chemotherapy, refinement of supportive care treatments, and development of novel therapeutics such as small molecule inhibitors, chimeric antigen receptor T-cell therapy, and immune checkpoint inhibitors. Unfortunately, many cancer-targeted therapies can lead to acute and chronic cardiovascular pathologies. The range of cardiotoxicity can vary but includes symptomatic or asymptotic heart failure, arrhythmias, coronary artery disease, valvar disease, pericardial disease, hypertension, and peripheral vascular disease. There is lack of data guiding primary prevention and treatment strategies in the pediatric population, which leads to substantial practice variability. Several important future research directions have been identified, including as they relate to cardiac disease, prevention strategies, management of cardiovascular risk factors, risk prediction, early detection, and the role of genetic susceptibility in development of cardiotoxicity. Continued collaborative research will be key in advancing the field. The ideal model for pediatric cardio-oncology is a proactive partnership between pediatric cardiologists and oncologists in order to better understand, treat, and ideally prevent cardiac disease in pediatric oncology patients.

Pediatric Sepsis Biomarker Risk Model Biomarkers and Estimation of Myocardial Dysfunction in Pediatric Septic Shock

OBJECTIVES

Sepsis-associated myocardial dysfunction is common in pediatric septic shock and negatively impacts outcomes. Early estimation of sepsis-associated myocardial dysfunction risk has the potential to inform clinical care and improve clinical trial design. The Pediatric Sepsis Biomarker Risk Model II is validated as a biomarker-based enrichment algorithm to discriminate children with septic shock with high baseline mortality probability. The objectives were to determine if Pediatric Sepsis Biomarker Risk Model biomarkers are associated with risk for sepsis-associated myocardial dysfunction in pediatric septic shock and to develop a biomarker-based model to reliably estimate sepsis-associated myocardial dysfunction risk.

DESIGN

Secondary analysis of prospective cohort study.

SETTING

Single-center, quaternary-care PICU.

PATIENTS

Children less than 18 years old admitted to the PICU from 2003 to 2018 who had Pediatric Sepsis Biomarker Risk Model biomarkers measured for determination of Pediatric Sepsis Biomarker Risk Model II mortality probability and an echocardiogram performed within 48 hours of septic shock identification.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Pediatric Sepsis Biomarker Risk Model II mortality probability was calculated from serum biomarker concentrations and admission platelet count. Echocardiograms were reread by a single cardiologist blinded to Pediatric Sepsis Biomarker Risk Model II data, and sepsis-associated myocardial dysfunction was defined as left ventricular ejection fraction less than 45% for primary analyses. Multivariable logistic regression analyzed the association of Pediatric Sepsis Biomarker Risk Model II mortality probability with sepsis-associated myocardial dysfunction. Classification and regression tree methodology was employed to derive a Pediatric Sepsis Biomarker Risk Model biomarker-based model for sepsis-associated myocardial dysfunction. Thirty-two of 181 children with septic shock demonstrated sepsis-associated myocardial dysfunction. Pediatric Sepsis Biomarker Risk Model II mortality probability was independently associated with sepsis-associated myocardial dysfunction (odds ratio, 1.45; 95% CI, 1.17-1.81; p = 0.001). Modeling with Pediatric Sepsis Biomarker Risk Model biomarkers estimated sepsis-associated myocardial dysfunction risk with an area under the receiver operating characteristic curve of 0.90 (95% CI, 0.85-0.95). Upon 10-fold cross-validation, the derived model had a summary area under the receiver operating characteristic curve of 0.74. Model characteristics were similar when sepsis-associated myocardial dysfunction was defined by both low left ventricular ejection fraction and abnormal global longitudinal strain.

CONCLUSIONS

A newly derived Pediatric Sepsis Biomarker Risk Model biomarker-based model reliably estimates risk of sepsis-associated myocardial dysfunction in pediatric septic shock, but independent prospective validation is needed.

The Effect of Adiposity on Cardiovascular Function and Myocardial Fibrosis in Patients With Duchenne Muscular Dystrophy

Background

Patients with Duchenne muscular dystrophy (DMD) develop cardiomyopathy because of a dystrophin deficiency causing fibrofatty replacement of the myocardium. Corticosteroid use and mobility limitations place these patients at risk for increased adiposity. We sought to determine the association of adiposity with cardiovascular dysfunction in patients with DMD.

Methods and Results

This was a retrospective review of patients with DMD who underwent both cardiac magnetic resonance imaging and dual‐energy x‐ray absorptiometry within 1 year. The cardiac magnetic resonance imaging parameters included left ventricular ejection fraction and the presence of late gadolinium enhancement (LGE positive [LGE+]). The adiposity indices, measured by dual‐energy x‐ray absorptiometry, included percentage of body fat, whole body fat mass indexed to height, and body mass index. A total of 324 patients were identified. Fifty‐two percent had LGE+, and 36% had cardiac dysfunction (left ventricular ejection fraction <55%). Patients with cardiac dysfunction had higher whole body fat mass indexed to height and body mass index on univariate analysis (mean difference between patients with and without cardiac dysfunction: +2.9 kg/m, P=0.001; and +1.5 kg/m², P=0.03, respectively). whole body fat mass indexed to height remained independently associated with cardiac dysfunction on multivariable analysis after adjusting for age, LGE+, and corticosteroid duration. High whole body fat mass indexed to height and percentage of body fat were associated with LGE+ on univariate analysis (mean difference between patients with and without LGE+: +2.0 kg/m, P=0.02; and +2.4%, P=0.02, respectively). Using multivariable analysis, including age and cardiac dysfunction, high percentage of body fat remained independently associated with LGE+.

Conclusions

This study demonstrates an independent association of adiposity with cardiac dysfunction and LGE+ in patients with DMD. Preventing adiposity may mitigate the later development of ventricular dysfunction in DMD.

The future is now! A supplemental webinar series to the First International Pediatric Cardio-Oncology Meeting

Planning for the First International Pediatric Cardio-Oncology Meeting has been underway since early 2019, with the original date in October 2020 delayed due to the COVID-19 pandemic. But patients continue to need care, research carries on, and the ability to learn from our colleagues remains one of the most important tools in our collective ability to advance the field. Through collaboration with Heart University (www.heartuniversity.org), a free web-based global education resource and training tool with an emphasis on acquired and congenital heart disease, we are able to provide colleagues around the world with focused sessions similar to those that will be expanded at the in-person meeting. The first such two-hour webinar was presented live online on December 16, 2020, and moving forward similar webinars will be offered approximately every other month for the next year leading up to the in-person meeting in 2022, with all sessions available online afterward for on-demand viewing. Although we are excited to get together with our colleagues in person, why wait until then to share what we know? The future is now!

V2 Trial: A phase I study of venetoclax and CPX-351 for young patients with relapsed/refractory acute leukemia

TPS7052

Background: Despite significant advances in therapy for acute myeloid leukemia (AML), 30-40% of young patients will relapse, after which prognosis is poor. In young patients, curative-intent salvage therapy involves intensive re-induction followed by hematopoietic stem cell transplant. Recently, the COG Phase II study of CPX-351 (liposomal cytarabine:daunorubicin, Vyxeos™) in pediatric patients with AML in first relapse (NCT02642965) demonstrated a CR/CRi rate of 81.3%. Separately, our first-in-pediatrics CPX-351 Phase I (NCT01943682) showed 48% in a heavily pre-treated pediatric cohort with multiply relapsed and refractory (R/R) AML. Our integrated pilot study of single cell RNA sequencing (scRNA-seq) done before, during, and after CPX-351 showed p53 targets over time with enrichment for genes regulating apoptosis (ex.: FAS, BAX), suggesting blasts may be primed for apoptosis following CPX-351. Venetoclax is a small molecule inhibitor of the anti-apoptotic protein BCL-2, a regulator of apoptotic balance in some leukemias. Based on our preclinical data, we developed a Phase I study to investigate venetoclax with CPX-351 for the treatment of young patients with R/R acute leukemias. Methods: The V2 Trial (NCT03826992) is a single-institution Phase I study to evaluate the safety and tolerability of venetoclax with CPX-351 in patients ages 1-39 years with R/R acute leukemias. Inclusion diagnoses include AML, mixed phenotype acute leukemia (MPAL), KMT2A-rearranged acute lymphoblastic leukemia (ALL), and T-ALL. Exclusion criteria include CNS status 3, bone marrow failure syndromes, and prior cardiotoxic exposures above acceptable risk thresholds. Subjects receive a single course of CPX-351 at the FDA approved adult dose on Days 1, 3, 5 with concurrent daily venetoclax. In the dose exploration phase, venetoclax dosing is 400 mg daily (or allometrically-scaled equivalent) for 21 (Dose Level 0) or 14 days (Dose Level -1) using a rolling 6 design. Primary endpoints are determination of the recommended phase 2 dose of venetoclax in combination with CPX-351 and description of toxicities. Secondary endpoints include estimations of CR/CRp/CRi +/- MRD negativity in the context of a phase I study and evaluation of therapy-related cardiac dysfunction. Correlative studies include analysis of venetoclax pharmacokinetics with concomitant CPX-351. At the initial dose level, DLT were encountered and the study is now continuing enrollment at Dose Level -1. Clinical trial information: NCT03826992.

Cardiovascular disease and its management in children and adults undergoing hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) is a potentially curative treatment for many malignancies, hemoglobinopathies, metabolic diseases, bone marrow failure syndromes, and primary immune deficiencies. Despite the significant improvement in survival afforded by HSCT, the therapy is associated with major short and long-term morbidity and mortality. Cardiovascular complications such as cardiomyopathy, arrhythmias, pulmonary hypertension, and pericardial effusions are increasingly recognized as potential outcomes following HSCT. The incidence of cardiac complications is related to various factors such as age, co-morbid medical conditions, whether patients received cardiotoxic chemotherapy prior to HSCT, the type of HSCT (autologous versus allogeneic), and the specific conditioning regimen. Thus, the cardiovascular evaluation has become a core component of the pre-transplant assessment, however, the practice differs from center to center as national guidelines and contemporary high-quality studies are lacking. We review the incidence of cardiotoxicity in pediatric and adult HSCT, potential mechanisms of injury, and effects on long-term outcomes. We also discuss the possible therapeutic approaches when disease arises, as well as the indications and need for surveillance before, during, and after transplantation.

Echocardiographic myocardial strain analysis describes subclinical cardiac dysfunction after craniospinal irradiation in pediatric and young adult patients with central nervous system tumors

Background

Craniospinal irradiation (CSI) is part of the treatment of central nervous system (CNS) tumors and is associated with cardiovascular disease in adults. Global myocardial strain analysis including longitudinal peak systolic strain (GLS), circumferential peak systolic strain (GCS), and radial peak systolic strain (GRS) can reveal subclinical cardiac dysfunction.

Methods

Retrospective, single-center study in patients managed with CSI vs. age-matched controls. Clinical data and echocardiography, including myocardial strain analysis, were collected at early (< 12 months) and late (≥ 12 months) time points after completion of CSI.

Results

Echocardiograms were available at 20 early and 34 late time points. Patients at the late time point were older (21.7 ± 10.4 vs. 13.3 ± 9.6 years) and further out from CSI (13.1 ± 8.8 vs. 0.2 ± 0.3 years). Standard echocardiographic parameters were normal for both groups. For early, CSI vs. control: GLS was − 16.8 ± 3.6% vs. -21.3 ± 4.0% (p = 0.0002), GCS was − 22.5 ± 5.2% vs. -21.3 ± 3.4% (p = 0.28), and GRS was 21.8 ± 11.0% vs. 26.9 ± 7.7% (p = 0.07). For late, CSI vs. control: GLS was − 16.2 ± 5.4% vs. -21.6 ± 3.7% (p < 0.0001), GCS was − 20.9 ± 6.8% vs. -21.9 ± 3.5% (p = 0.42), and GRS was 22.5 ± 10.0% vs. 27.3 ± 8.3% (p = 0.03). Radiation type (proton vs. photon), and radiation dose (< 30 Gy vs. ≥ 30 Gy) did not impact any parameter, although numbers were small.

Conclusions

Subclinical cardiac systolic dysfunction by GLS is present both early and late after CSI. These results argue for future studies to determine baseline cardiovascular status and the need for early initiation of longitudinal follow-up post CSI.

Left Ventricular Magnetic Resonance Imaging Strain Predicts the Onset of Duchenne Muscular Dystrophy-Associated Cardiomyopathy

BACKGROUND

Early detection of left ventricular (LV) dysfunction before the onset of overt Duchenne muscular dystrophy-associated cardiomyopathy (DMDAC) may direct clinical management to slow onset of dysfunction. We aimed to assess whether LV strain will predict those who develop DMDAC.

METHODS

We performed a single center retrospective case control study of patients with Duchenne muscular dystrophy who underwent serial cardiac magnetic resonance between 2006 and 2019. Patients with Duchenne muscular dystrophy with an LV ejection fraction ≥55% on ≥1 cardiac magnetic resonance were identified and grouped into age-matched +DMDAC and -DMDAC. Within 3 years, +DMDAC had a subsequent cardiac magnetic resonance with a decline in LV ejection fraction ≥10% and absolute LV ejection fraction ≤50%. -DMDAC maintained an LV ejection fraction ≥55% on serial cardiac magnetic resonances. Two-dimensional and 3-dimensional global radial strain, global circumferential strain (GCS), and global longitudinal strain were measured using tissue tracking software and their ability to predict DMDAC onset was assessed. Multivariable analysis adjusted for late gadolinium enhancement.

RESULTS

Thirty +DMDAC and 30 age-matched -DMDAC patients were included with a total of 164 studies analyzed. Before DMDAC onset, 2-dimensional global radial strain and GCS were significantly worse in +DMDAC compared with -DMDAC (25.1±6.0 versus 29.0±6.3, P=0.011; -15.4%±2.4 versus -17.3%±2.6, P=0.003). Three-dimensional GCS and global radial strain had similar findings. Among strain measures, 3-dimensional GCS had the highest area under the curve to predict DMDAC in our cohort. These findings persisted after adjusting for the presence of late gadolinium enhancement.

CONCLUSIONS

Reduced global radial strain and GCS may predict those at risk for developing DMDAC before onset of LV dysfunction and its clinical utility warrants further exploration.

Variations in native T1 values in patients with Duchenne muscular dystrophy with and without late gadolinium enhancement

Duchenne muscular dystrophy (DMD) is an X-linked genetic disorder leading to progressive skeletal and cardiac myopathy. Elevated myocardial T1 values correlate with fibrosis in most disease processes, but DMD skeletal and cardiac histopathology is defined by fibrofatty replacement that may result in a decrease in T1 values, due to the low T1 of fat. The study goal was to assess myocardial T1 values in DMD patients with and without late gadolinium enhancement (LGE). A retrospective analysis was performed on all patients with DMD referred for CMR at our institution from 7/5/2017 to 10/24/2018. T1 measurements were performed using breath-held modified Look Locker inversion recovery (MOLLI) sequences at the basal and mid-ventricular levels. The cohort was separated into patients without the presence of LGE (LGE-) and patients with current or previous LGE (LGE+). A total of 207 CMR studies were analyzed. The LGE- group comprised 88 patients while 119 patients were in the LGE+ group. The LGE+ group was older, had larger indexed LV end-diastolic volume and lower LV ejection fraction (LVEF) compared to the LGE- group. T1 values in the LGE+ group were lower compared to the LGE- group (mid T1 1012 ms vs. 1035 ms; p = 0.002), with 5 CMR studies demonstrating mid T1 values < 900 ms. There was no correlation between mid T1 and LVEF in the LGE- group. In the LGE+ cohort, lower T1 values correlated with worse LVEF (r = 0.34, p = 0.0002). The association between mid T1 values and LVEF remained statistically significant on multivariable analysis when accounting for number of LGE segments, LVEDVi, and age (p = 0.009). This is the largest study assessing native T1 values in patients with DMD. The results demonstrate that patients with LGE had lower T1 values than patients without LGE. In the LGE+ group, lower T1 values correlated with worse LV systolic function. These results are consistent with the evolving recognition of fibrofatty replacement in advanced stages of DMD myopathy. Furthermore, our study supports that there is not a simple linear relationship between increasing T1 values and advancing disease progression reported in most other cardiomyopathies.

Cardiovascular disease and asymptomatic childhood cancer survivors: Current clinical practice

BACKGROUND

It is poorly understood how cardiovascular screening in asymptomatic childhood cancer survivors (CCS) is applied to and impacts clinical care.

OBJECTIVES

To describe the current role of cardiovascular screening in the clinical care of asymptomatic CCS.

METHODS

At 50 pediatric academic medical centers, a childhood cancer survivorship clinic director, pediatric cardiologist, and adult cardiologist with a focus on CCS were identified and invited to participate in a survey. Surveys were managed electronically. Categorical data were analyzed using nonparametric methods.

RESULTS

Of the 95 (63%) respondents, 39% were survivorship practitioners, and 61% were cardiologists. Eighty-eight percent of survivorship practitioners reported that greater than half of CCS received cardiovascular screening. CCS followed by adult cardiology were more likely to be seen by a cardio-oncologist. Those followed by pediatric cardiology were more likely to be seen by a heart failure/transplant specialist. Common reasons for referral to cardiology were abnormal cardiovascular imaging or concerns a CCS was at high risk for cardiovascular disease. Ninety-two percent of cardiologists initiated angiotensin converting enzyme inhibitor or angiotensin receptor blocker therapy for mild systolic dysfunction. Adult cardiologists initiated beta-blocker therapy for less severe systolic dysfunction compared to pediatric cardiologists (P < .001). Pediatric cardiologists initiated mineralocorticoid therapy for less severe systolic dysfunction compared to adult cardiologists (P = .025). Practitioners (93%) support a multi-institutional collaboration to standardize cardiovascular care for CCS.

CONCLUSIONS

While there is much common ground in the clinical approach to CCS, heterogeneity is evident. This highlights the need for cohesive, multi-institutional, standardized approaches to cardiovascular management in CCS.

Educational and learning morbidity in pediatric heart transplant recipients: A pediatric heart transplant society study

Educational development is an important component of quality of life for children with heart transplant. Aims include determining prevalence of and risk factors for modified education placement in a large representative sample of pediatric heart transplant recipients. Participants included 1495 patients (age 6-18 years) from the PHTS database. Data on education placement and clinical predictors were collected at listing and at 1 and 3 years post-transplant. At listing, 88% of patients were in typical education placement, while 12% were in modified education. Males (P = .02), those with CHD (P < .0001), those with non-private insurance (P < .0001), and those with longer hospital stay (P = .001) were more likely to be in a modified education placement at time of listing. Age, race, listing status, mechanical support, and waitlist time were not significantly associated with placement. The prevalence of typical education placement was similar (87% at 1-year and 86% at 3-year) post-transplant. Predictors of modified education placement at 3-year follow-up included placement at listing (OR = 12.9 [95% CI 7.6-21.9], P < .0001), non-private insurance (OR = 2.0 [95% CI 1.3-3.2], P = .001), CHD (OR = 1.8 [95% CI 1.1-2.7, P = .01), history of post-transplant infection (OR = 1.9 [95% CI 1.2-2.9, P = .007), and number of post-transplant infections (OR = 1.3 [95% CI 1.1-1.5, P = .002). Among pediatric heart transplant recipients, males, those with non-private insurance, those with CHD, and those who experience post-transplant infections are at greatest risk for modified academic placement, which persists for several years post-transplant and deserves targeted intervention.

Heart Transplantation in Muscular Dystrophy Patients: Is it a Viable Option?

BACKGROUND

Cardiomyopathy is a common complication among muscular dystrophy (MD) patients and often results in advanced heart failure and premature death. In spite of this, there is hesitancy to consider heart transplantation (HTx). This study describes the HTx outcomes in patients with MD in the United States.

METHODS AND RESULTS

All HTx in the United Network for Organ Sharing database from October 1, 1987, to March 31, 2016, were identified. Two patient groups were created: MD cohort (n=81), and a cohort of all other cardiomyopathies, called cardiomyopathy-unmatched (n=41 317). Propensity score matching (ratio 1:2) was performed on transplant age, gender transplant year, renal function, and inotropic support at transplant to form a cardiomyopathy-matched cohort (n=162). Patient characteristics and posttransplant outcomes were compared. In the 81 patients with MD, Becker was the most common type (42%-52%). All the analyzed preoperative characteristics did not statistically differ between the MD and cardiomyopathy-matched cohorts except ventricular assist device use (16% versus 30%; P=0.017), ventilator support (0% versus 6%; P=0.031), and donor race mismatch (30% versus 55%; P<0.001). Median time on waitlist was not statistically different between the 2 groups (52 versus 59 days; P=0.12). Posttransplant survival of MD cohort was not statistically different compared with cardiomyopathy-matched cohort (P=0.18; hazard ratio [95% CI], 0.71 [0.42-1.18]) and was better than the cardiomyopathy-unmatched cohort (P=0.004; hazard ratio [95% CI], 0.53 [0.34-0.82]). Among the types of MD, no statistical difference was observed in posttransplant survival of Becker MD versus non-Becker MD (P=0.12; hazard ratio [95% CI], 2.17 [0.79-6.01]).

CONCLUSIONS

Patients with MD undergoing HTx had similar long-term posttransplant survival compared with matched cardiomyopathy-related HTx recipients. HTx appears to be an effective treatment for a select group of muscular dystrophy patients with end-stage heart failure.

Repeated Remote Ischemic Conditioning Reduces Doxorubicin-Induced Cardiotoxicity

Objectives

This study investigated the cardioprotective effect of repeated remote ischemic preconditioning (rRIC) on doxorubicin-induced cardiotoxicity in mice.

Background

Doxorubicin is an effective chemotherapeutic agent for a wide range of tumor types but its use and dosing are limited by acute and chronic cardiotoxicity. Remote ischemic conditioning (RIC) is cardioprotective in multiple cardiovascular injury models, but the effectiveness of rRIC in doxorubicin-induced cardiotoxicity has not been fully elucidated.

Methods

rRIC was performed on mice before and after doxorubicin administration. Cardiac function was assessed by echocardiography and myocardial biology was tested by molecular approaches.

Results

Doxorubicin administration induced acute cardiotoxicity, as indicated by reduced cardiac function, reduced myocyte cross-section area and increased extracellular collagen deposition, increased circulating cardiac muscle damage markers, and decreased heart weight. Doxorubicin also adversely affected other organs, including the kidney, liver, and spleen, as evaluated by circulating markers or organ weight loss. rRIC not only abrogated doxorubicin-induced cardiotoxicity (left ventricular ejection fraction, doxorubicin 47.5 ± 1.1%, doxorubicin + rRIC 51.6 ± 0.7%, p = 0.017), but also was associated with multiorgan protection. Within the myocardium, rRIC attenuated doxorubicin-induced cardiomyocyte apoptosis, reduced inflammation, and increased autophagy signaling.

Conclusions

rRIC may be a promising approach to reduce doxorubicin-induced cardiotoxicity.

Preparing the Cardiovascular Workforce to Care for Oncology Patients: JACC Review Topic of the Week

Cardiovascular disease and cancer are the 2 main causes of death in the United States. They intersect on multiple levels, sharing common causal mechanisms and epidemiological risk factors. The growing prevalence and complexity of cardiovascular disease and cancer have resulted in the development of the discipline of cardio-oncology. Preparing the cardiovascular workforce for the care of a growing population of cancer patients is necessary to enhance the delivery of high-quality cardiovascular care for patients with cancer. The goal of this review is to present the dedicated efforts of the cardio-oncology community to meet the growing need for education and training of cardiovascular practitioners providing care to cancer patients and survivors. Integration in general cardiology training programs and the efforts of the stakeholder organizations serve as an example of how a multidimensional, innovative approach can address provider education and training needs in a relatively new discipline.

Cardiovascular Toxicities in Pediatric Cancer Survivors

Advances in cancer therapies have significantly improved patient outcomes. However, with improvements in survival, the toxicities associated with cancer therapy have become of paramount importance and oncologists are faced with the challenge of establishing therapeutic efficacy while minimizing toxicity. Cardiovascular disease represents a significant risk to survivors of childhood cancer and is a major cause of morbidity and mortality. This article outlines the current state of knowledge regarding cardiotoxicity in children undergoing cancer therapies, including the impact of specific oncologic therapies, recommendations for cardiovascular screening, the management of established cardiac disease, and the evolving field of pediatric cardio-oncology.

Chimeric Antigen Receptor T-Cell Therapy for Cancer and Heart: JACC Council Perspectives

Chimeric antigen receptor (CAR) T-cell therapy has significantly advanced the treatment of patients with relapsed and refractory hematologic malignancies and is increasingly investigated as a therapeutic option of other malignancies. The main adverse effect of CAR T-cell therapy is potentially life-threatening cytokine release syndrome (CRS). Clinical cardiovascular (CV) manifestations of CRS include tachycardia, hypotension, troponin elevation, reduced left ventricular ejection fraction, pulmonary edema, and cardiogenic shock. Although insults related to CRS toxicity might be transient and reversible in most instances in patients with adequate CV reserve, they can be particularly challenging in higher-risk, often elderly patients with pre-existing CV disease. As the use of CAR T-cell therapy expands to include a wider patient population, careful patient selection, pre-treatment cardiac evaluation, and CV risk stratification should be considered within the CAR T-cell treatment protocol. Early diagnosis and management of CV complications in patients with CRS require awareness and multidisciplinary collaboration.

The landscape of cardiovascular care in pediatric cancer patients and survivors: a survey by the ACC Pediatric Cardio-Oncology Work Group

Objective

To enhance the understanding of cardiovascular care delivery in childhood cancer patients and survivors.

Study design

A 20-question survey was created by the Pediatric Cardio-oncology Work Group of the American College of Cardiology (ACC) Cardio-oncology Section to assess the care, management, and surveillance tools utilized to manage pediatric/young adult cardio-oncology patients. The survey distribution was a collaborative effort between Cardio-oncology Section and membership of the Adult Congenital and Pediatric Cardiology Section (ACPC) of the ACC.

Results

Sixty-five individuals, all self-identified as physicians, responded to the survey. Most respondents (n = 58,89%) indicated childhood cancer patients are regularly screened prior to and during cancer therapy at their centers, predominantly by electrocardiogram (75%), standard echocardiogram (58%) and advanced echocardiogram (50%) (i.e. strain, stress echo). Evaluation by a cardiologist prior to/during therapy was reported by only 8(12%) respondents, as compared to post-therapy which was reported by 28 (43%, p < 0.01). The most common indications for referral to cardiology at pediatric centers were abnormal test results (n = 31,48%) and history of chemotherapy exposure (n = 27,42%). Of note, during post-treatment counseling, common cardiovascular risk-factors like blood pressure (31,48%), lipid control (22,34%), obesity & smoking (30,46%) and diet/exercise/weight loss (30,46%) were addressed by fewer respondents than was LV function (72%).

Conclusions

The survey data demonstrates that pediatric cancer patients are being screened by EKG and/or imaging prior to/during therapy at most centers. Our data, however, highlight the potential for greater involvement of a cardiovascular specialist for pre-treatment evaluation process, and for more systematic cardiac risk factor counseling in posttreatment cancer survivors.

Heart transplantation in survivors of childhood cancer

There are approximately 450,000 survivors of childhood cancer due, in large part, to successes of therapeutic regimens. With this success comes an increase in the number of patients developing cardiotoxicity as a result of cancer therapies. In certain cases, this includes heart failure recalcitrant to medical therapy, and consideration for heart transplantation may be necessary. However, this group of patients has unique comorbidities that may affect outcomes. Despite this, available data show that complications and overall survival are similar for patients transplanted for anthracycline-induced cardiomyopathy compared to those with other cardiomyopathies, demonstrating that this is a viable treatment option for this population. As other cancer therapies become more common, new cardiovascular toxicities are recognized. Whether heart transplantation will be appropriate for all patients with cancer-therapy related cardiotoxicity (CTRC) will require demonstration of similarly good outcomes to ensure proper allocation of organs.

Wearable cardioverter-defibrillators in pediatric cardiomyopathy: A cost-utility analysis

BACKGROUND

Dilated cardiomyopathy (DCM) is the most common cardiomyopathy in children. Patients with severe cardiac dysfunction are thought to be at risk of sudden cardiac arrest (SCA). After diagnosis, a period of medical optimization is recommended before permanent implantable cardioverter-defibrillator (ICD) implantation. Wearable cardioverter-defibrillators (WCDs) provide an option for arrhythmia protection as an outpatient during this optimization.

OBJECTIVE

The purpose of this study was to determine the strategy that optimizes cost and survival during medical optimization of a patient with DCM before ICD placement.

METHODS

A Markov state transition model was constructed for the 3 clinical approaches to compare costs, clinical outcomes, and quality of life: (1) "Inpatient," (2) "Home-WCD," and (3) "Home-No WCD." Transitional probabilities, costs, and utility metrics were extracted from the existing literature. Cost-effectiveness was assessed comparing each paradigm's incremental cost-effectiveness ratio against a societal willingness-to-pay threshold of $50,000 per quality-adjusted life year.

RESULTS

The cost-utility analysis illustrated that Home-WCD met the willingness-to-pay threshold with an incremental cost-effectiveness ratio of $20,103 per quality-adjusted life year and 4 mortalities prevented per 100 patients as compared with Home-No WCD. One-way sensitivity analyses demonstrated that Home-No WCD became the most cost-effective solution when the probability of SCA fell below 0.2% per week, the probability of SCA survival with a WCD fell below 9.8%, or the probability of SCA survival with Home-No WCD quadrupled from base-case assumptions.

CONCLUSION

Based on the existing literature probabilities of SCA in pediatric patients with DCM undergoing medical optimization before ICD implantation, sending a patient home with a WCD may be a cost-effective strategy.

New-onset diabetes after pediatric heart transplantation: A review of the Pediatric Heart Transplant Study

NDT is a well-defined complication after solid organ transplantation. Little has been published describing the incidence, risk factors, and effect on outcome after pediatric heart transplantation. We performed a retrospective evaluation of pediatric patients from the PHTS registry from 2004 to 2014. Group comparison, associated factors, incidence using Kaplan-Meier method, and risk factor and outcome analysis for NDT at 1 year post-transplant. Of the 2185 recipients, 1756 were alive and followed at 1 year. Overall freedom from NDT was 98.9%, 94.7%, and 92.6% at 1, 5, and 10 years, respectively. Patients with NDT were more likely to be black (non-Hispanic; P = 0.002), older at time of transplant (P < 0.0001), and have a higher BMI percentile at time of transplant (P < 0.0001). Adjusted risk factors for NDT at 1 year were older age at transplant (years; >12 years, OR: 8.8 and 5-12 years, HR: 8.0), obese BMI percentile at time of transplant (OR: 3.8), and steroid use at 30 days after transplant (OR: 4.7). Though uncommon, NDT occurs with a constant hazard after pediatric heart transplant; it occurs more often in older patients at transplant, those who are of black race, those who are obese, and those who use steroids. Therefore, targeted weight reduction and selective steroid use in at-risk populations could reduce the incidence of early NDT. Further data are needed to determine the risk imparted by transplantation, factors that predict late-onset NDT, and whether NDT alters the outcome after transplant.

Contemporary Outcomes of Pediatric Restrictive Cardiomyopathy: A Single-Center Experience

BACKGROUND

Pediatric restrictive cardiomyopathy (RCM) has high mortality in historical cohorts, and traditional management often involves early referral for heart transplantation (HTx). This study sought to determine outcomes of pediatric RCM at a center that has favored medical management over early listing for HTx.

METHODS

All patients (N = 43) with pure RCM phenotype (RCM, N = 26) and hypertrophic cardiomyopathy with restrictive physiology (RCM/HCM, N = 17) managed at our center over a 15-year period were investigated. Outcomes of those listed for HTx (N = 18) were compared to a benchmark of contemporaneous pediatric RCM patients in the UNOS database (N = 377). Proportional hazards models were used to determine predictors of adverse outcomes.

RESULTS

The mean age was 11 ± 9 years and 49% were male. 14 of 18 patients listed received HTx. Overall mortality (12%) was identical between the phenotypes; however, RCM patients were more likely to be listed (P = 0.001) and receive HTx (P = 0.02) compared to RCM/HCM. Prior to HTx, 60% had documented arrhythmia, 16% had cardiac arrest, and 7% required mechanical circulatory support. 4 of 17 patients with an ICD/PM received device therapies (four of five shocks appropriate for VT/VF, and two effective anti-tachycardia pacing interventions). Outcomes of those listed for HTx at our center were similar to the UNOS benchmark. In multivariate analysis, markers of congestive heart failure were associated with adverse outcomes.

CONCLUSION

Heart failure and arrhythmia treatments can delay or possibly prevent the need for HTx in some cases of pediatric RCM. Survival post-HTx is not compromised using this approach.

Cardiovascular Disease in Survivors of Childhood Cancer: Insights Into Epidemiology, Pathophysiology, and Prevention

Cardiovascular disease (CVD), which includes cardiomyopathy/heart failure, coronary artery disease, stroke, pericardial disease, arrhythmias, and valvular and vascular dysfunction, is a major concern for long-term survivors of childhood cancer. There is clear evidence of increased risk of CVD largely attributable to treatment exposures at a young age, most notably anthracycline chemotherapy and chest-directed radiation therapy, and compounded by traditional cardiovascular risk factors accrued during decades after treatment exposure. Preclinical studies are limited; thus, it is a high priority to understand the pathophysiology of CVD as a result of anticancer treatments, taking into consideration the growing and developing heart. Recently developed personalized risk prediction models can provide decision support before initiation of anticancer therapy or facilitate implementation of screening strategies in at-risk survivors of cancer. Although consensus-based screening guidelines exist for the application of blood and imaging biomarkers of CVD, the most appropriate timing and frequency of these measures in survivors of childhood cancer are not yet fully elucidated. Longitudinal studies are needed to characterize the prognostic importance of subclinical markers of cardiovascular injury on long-term CVD risk. A number of prevention trials across the survivorship spectrum are under way, which include primary prevention (before or during cancer treatment), secondary prevention (after completion of treatment), and integrated approaches to manage modifiable cardiovascular risk factors. Ongoing multidisciplinary collaborations between the oncology, cardiology, primary care, and other subspecialty communities are essential to reduce therapeutic exposures and improve surveillance, prevention, and treatment of CVD in this high-risk population.

Obesity class does not further stratify outcome in overweight and obese pediatric patients after heart transplantation

The effect of obesity stratification on pediatric heart transplant outcomes is unknown. The UNOS database was queried for patients ≥2-<18 years listed for heart transplant and stratified by BMI: normal (BMI>5%-≤85 percentile), overweight (BMI=86%-95 percentile), class 1 (BMI=100%-120% of 95 percentile), class 2 (BMI=121%-140% of 95 percentile), and class 3 obesity (BMI>140% of 95 percentile). A total of 5056 individuals were listed for transplant, with 71% normal, 13% overweight, 10% class 1, 4% class 2, and 2% class 3 obesity. Waitlist survival was not different between groups. Post-transplant survival was decreased in overweight and combined obese groups vs normal, with no further difference between overweight and obese classes. Overweight and obese patients had higher listing status and were more likely to have ventilator, inotrope, and mechanical circulatory support at listing. After transplant, there was an association of overweight-obese patients with diabetes and rejection requiring hospitalization. Stricter definition of normal weight reveals overweight-obese status was an independent risk factor for poorer post-transplant survival, without further effect by stratification of weight class. However, because there is no difference in waitlist survival, this study does not allow the selection of absolute weight-based criteria regarding transplant listing and suggests the need to look further for modifiable risk factors post-transplant.

Cardiotoxicity and cardiomyopathy in children and young adult survivors of hematopoietic stem cell transplant

Cardiomyopathy is common in long-term survivors of pediatric hematopoietic stem cell transplant (HSCT). Events occurring before and after HSCT when combined with specific insults during HSCT likely contribute to long-term risk. Strategies for detecting subclinical cardiomyopathy prior to patients developing overt heart failure are under investigation. Changes in HSCT preparative regimens and cardioprotective medications administered during chemotherapy may alter the risk for cardiomyopathy. Interventions in long-term survivors such as lifestyle modification and cardioactive medications are of increasing importance. Herein we review the causes of cardiac injury, discuss strategies for detection of cardiomyopathy, and evaluate therapeutic options for long-term HSCT survivors.

Airway plaque presenting after alteration of immunosuppression in a pediatric patient remote from heart transplantation

Success after solid organ transplantation is dependent on the proper balance of immunosuppression to prevent rejection of the allograft while limiting the risk of developing infections and malignancy. We present a 9-year-old girl, remote from transplant, who presented with airway plaque after a change in immunosuppression to include the mTOR inhibitor sirolimus. Differential diagnosis included direct medication side effect, infection, and neoplasia.

Team-based approach to identify cardiac toxicity in critically ill hematopoietic stem cell transplant recipients

INTRODUCTION

We observed pulmonary hypertension (PH), pericardial effusions, and left ventricular systolic dysfunction (LVSD) in multiple critically ill hematopoietic stem cell transplant (HSCT) recipients. We implemented routine structured echocardiography screening for HSCT recipients admitted to the pediatric intensive care unit (PICU) using a standardized multidisciplinary process.

METHODS

HSCT recipients admitted to the PICU with respiratory distress, hypoxia, shock, and complications related to transplant-associated thrombotic microangiopathy were screened on admission and every 1-2 weeks thereafter. Echocardiography findings requiring intervention and/or further screening included elevated right ventricular pressure, LVSD, and moderate to large pericardial effusions. All echocardiograms were compared to the patient's routine pretransplant echocardiogram.

RESULTS

Seventy HSCT recipients required echocardiography screening over a 3-year period. Echo abnormalities requiring intervention and/or further screening were found in 35 (50%) patients. Twenty-four (34%) patients were noted to have elevated right ventricular pressure; 14 (20%) were at risk for PH, while 10 (14%) had PH. All patients with PH were treated with pulmonary vasodilators. LVSD was noted in 22 (31%) patients; 15/22 (68%) received inotropic support. Moderate to large pericardial effusions were present in nine (13%) patients, with six needing pericardial drain placement.

DISCUSSION

Echocardiographic abnormalities are common in critically ill HSCT recipients. Utilization of echocardiogram screening may allow for early detection and timely intervention for cardiac complications in this high-risk cohort.

Cardiac Dysfunction and Heart Failure in Hematopoietic Cell Transplantation Survivors: Emerging Paradigms in Pathophysiology, Screening, and Prevention

Hematopoietic cell transplantation (HCT) has been used for curative intent in patients with hematologic and nonhematologic malignancies, resulting in an increasing number of HCT survivors. These survivors are at risk for serious and life-threatening complications, including cardiovascular disease (CVD). This article provides an overview of CVD in HCT survivors, describing the pathophysiology of disease, with a special emphasis on therapeutic exposures and comorbidities unique to this population. This article also discusses novel screening and prevention strategies that have shown promise in non-HCT cancer populations, emphasizing opportunities for collaboration between cardiologists and hematologists to improve the cardiovascular health of HCT survivors.

Central Arterial Function Measured by Non-invasive Pulse Wave Analysis is Abnormal in Patients with Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder caused by mutation of dystrophin. Cardiovascular involvement includes dilated cardiomyopathy. Non-invasive assessment of vascular function has not been evaluated in DMD. We hypothesize arterial wave reflection is abnormal in patients with DMD. Pulse wave analysis was performed on DMD patients with a SphygmoCor SCOR-PVx System to determine central blood pressure and augmentation index (AIx) as an assessment of arterial wave reflection. Results were compared to a control group. A total of 43 patients with DMD were enrolled, and compared to 43 normal controls. Central systolic blood pressure was lower, while both AIx-75 (7.8 ± 9.6% vs. 2.1 ± 10.4%, p 0.01, DMD vs. normal) and AIx-not corrected (16.8 ± 10.1% vs. -3.6 ± 10.9, p < 0.001, DMD vs. normal) were higher in the DMD compared to control. Using multivariable linear regression model, the variables found to have a significant effect on AIx-not corrected included diagnosis of DMD, height, and heart rate (r ² = 0.257). The current data suggest that, despite lower central systolic blood pressure, patients with DMD have higher wave reflection when compared to normal controls, which may represent increased arterial stiffness. Overall there appears to be no effect on ventricular systolic function, however the long-term consequence in this group is unknown. Further study is required to determine the mechanism of these differences, which may be related to the effects of systemic steroids or the role of dystrophin in vascular function.

Pediatric cardiac transplantation

Heart transplantation in pediatric patients generally arises as a treatment option of last resort, that is, the indication is for patients with heart failure of various etiologies, with potential or actual end-organ dysfunction, in whom there are no reasonable, long-term options for life-prolonging therapy. The concept of heart failure is complex in a pediatric population, particularly those with congenital heart disease. While heart failure may refer simply to systolic dysfunction leading to low cardiac output, it can also encompass: diastolic dysfunction in restrictive cardiomyopathy; single ventricle physiology without an option for stable palliation. A good candidate should have a predicted life expectancy less than the median lifetime of a transplanted heart. Significant improvement in survival has been observed over time with 1- and 5-year survival approximately 90% and 80% in the contemporary era.

The injured heart: early cardiac effects of hematopoietic stem cell transplantation in children and young adults

We hypothesized that subclinical cardiac injury in the peri-transplant period is more frequent than currently appreciated in children and young adults. We performed echocardiographic screening on 227 consecutive patients prior to hematopoietic stem cell transplantation (HSCT), and 7, 30 and 100 days after transplant. We measured cardiac biomarkers cardiac troponin-I (cTn-I), and soluble suppressor of tumorigenicity 2 (sST2) prior to transplant, during conditioning, and days +7, +14, +28 and +49 in 26 patients. We subsequently analyzed levels of cTn-I every 48-72 h in 15 consecutive children during conditioning. Thirty-two percent (73/227) of patients had a new abnormality on echocardiogram. New left ventricular systolic dysfunction (LVSD) occurred in 6.2% of subjects and new pericardial effusion in 27.3%. Eight of 227 (3.5%) patients underwent pericardial drain placement, and 5 (2.2%) received medical therapy for clinically occult LVSD. cTn-I was elevated in 53.0% of all samples and sST2 in 38.2%. At least one sample had a detectable cTn-I in 84.6% of patients and an elevated sST2 in 76.9%. Thirteen of fifteen patients monitored frequently during condition had elevation of cTn-I. Echocardiographic and biochemical abnormalities are frequent in the peri-HSCT period. Echocardiogram does not detect all subclinical cardiac injuries that may become clinically relevant over longer periods.