The Prevalence and Association of Exercise Test Abnormalities With Sudden Cardiac Death and Transplant-Free Survival in Childhood Hypertrophic Cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) can be associated with an abnormal exercise response. In adults with HCM, abnormal results on exercise stress testing are predictive of heart failure outcomes. Our goal was to determine whether an abnormal exercise response is associated with adverse outcomes in pediatric patients with HCM. METHODS: In an international cohort study including 20 centers, phenotype-positive patients with primary HCM who were <18 years of age at diagnosis were included. Abnormal exercise response was defined as a blunted blood pressure response and new or worsened ST- or T-wave segment changes or complex ventricular ectopy. Sudden cardiac death (SCD) events were defined as a composite of SCD and aborted sudden cardiac arrest. Using Kaplan-Meier survival, competing outcomes, and Cox regression analyses, we analyzed the association of abnormal exercise test results with transplant and SCD event-free survival. RESULTS: Of 724 eligible patients, 630 underwent at least 1 exercise test. There were no major differences in clinical characteristics between those with or without an exercise test. The median age at exercise testing was 13.8 years (interquartile range, 4.7 years); 78% were male and 39% were receiving beta-blockers. A total of 175 (28%) had abnormal test results. Patients with abnormal test results had more severe septal hypertrophy, higher left atrial diameter z scores, higher resting left ventricular outflow tract gradient, and higher frequency of myectomy compared with participants with normal test results (P<0.05). Compared with normal test results, abnormal test results were independently associated with lower 5-year transplant-free survival (97% versus 88%, respectively; P=0.005). Patients with exercise-induced ischemia were most likely to experience all-cause death or transplant (hazard ratio, 4.86 [95% CI, 1.69-13.99]), followed by those with an abnormal blood pressure response (hazard ratio, 3.19 [95% CI, 1.32-7.71]). Exercise-induced ischemia was also independently associated with lower SCD event-free survival (hazard ratio, 3.32 [95% CI, 1.27-8.70]). Exercise-induced ectopy was not associated with survival. CONCLUSIONS: Exercise abnormalities are common in childhood HCM. An abnormal exercise test result was independently associated with lower transplant-free survival, especially in those with an ischemic or abnormal blood pressure response with exercise. Exercise-induced ischemia was also independently associated with SCD events. These findings argue for routine exercise testing in childhood HCM as part of ongoing risk assessment.

Progress in Noninvasive Surveillance for Acute Rejection in Pediatric Heart Transplant Recipients: A Real-World Analysis of Donor-Derived Cell-Free DNA-Based Surveillance Protocol.

PURPOSE: Acute cellular (ACR) and antibody-mediated (AMR) rejection are risk factors for allograft loss in heart transplant (HT) recipients. Endomyocardial biopsy (EMB), although considered the gold standard for rejection surveillance, is invasive and has high interobserver variability. Noninvasive donor-derived cell-free DNA (dd-cfDNA) sampling has a high negative predictive value (NPV) for rejection in adults and is increasingly used in pediatrics. This single center study aimed to test the performance of dd-cfDNA in screening for acute rejection (AR) and donor-specific antibodies (DSAs) in pediatric HT recipients. METHODS: Blood samples for dd-cfDNA were obtained per clinical protocol for all eligible HT recipients in our center from July 1, 2022 to December 31, 2023. Primary endpoints were episodes of AR, pathology grading of EMBs temporally related to ddcfDNA sampling (0-150 days), and presence of DSAs. RESULTS: There were 471 interpretable samples, in 192 unique patients. Of those, 199 dd-cfDNA tests were paired with EMB ± DSA in 152 patients. Abnormal dd-cfDNA (> 0.2%) was found in 77 samples (median 0.48%, range 0.21%-11%) and led to EMB, where one sample was positive for ACR (grade 2R), 13 for AMR, yielding an NPV of 97% for AMR. After excluding abnormal ddcfDNA testing associated with AR, 65 abnormal dd-cfDNA tests were paired with DSA testing. The NPV of the test for detection of DSAs was 93%. CONCLUSION: Implementation of noninvasive rejection surveillance with dd-cfDNA in a pediatric cohort demonstrates high NPV for AR and high DSAs, making it an ideal screening tool for long-term monitoring of allograft health in pediatrics.

Long-term outcomes for pediatric heart transplant recipients transitioning to adult care teams.

BACKGROUND: There are limited data evaluating the success of a structured transition plan specifically for pediatric heart transplant (HT) recipients following their transfer of care to an adult specialist. We sought to identify risk factors for poor adherence, graft failure, and mortality following the transfer of care to adult HT care teams. METHODS: We retrospectively reviewed all patients who underwent transition from the pediatric to adult HT program at our center between January 2011 and June 2021. Demographic characteristics, comorbid conditions, and psychosocial history were collected at the time of HT, the time of transition, and the most recent follow-up. Adverse events including mortality, graft rejection, infection, and renal function were also captured before and after the transition. RESULTS: Seventy-two patients were identified (54.1% male, 54.2% Caucasian). Mean age at the time of transition was 23 years after a median of 11.6 years in the pediatric program. The use of calcineurin inhibitors was associated with reduced mortality (HR .04, 95% CI .0-.6, p = .015), while prior psychiatric hospitalization (HR 45.3, 95% CI, 6.144-333.9, p = .0001) was associated with increased mortality following transition. Medication nonadherence and young age at the time of transition were markers for high-risk individuals prior to the transition of care. CONCLUSIONS: Transition of HT recipients from a pediatric program to an adult program occurs during a vulnerable time of emerging adulthood, and we have identified risk factors for mortality following transition. Development of a formalized transition plan with a large multidisciplinary team with focused attention on high-risk patients, including those with psychiatric comorbidities, may favorably influence outcomes.

Advances in understanding and managing pediatric heart failure and transplant.

PURPOSE OF REVIEW: This article highlights the most recent advances in a review of the current literature in the field of pediatric heart failure and transplantation. RECENT FINDINGS: Diagnostically, the identification of new genetic factors has contributed to a deeper understanding of cardiomyopathy in children. Novel medications like sacubitril/valsartan and Sodium-Glucose cotransporter-2 (SGLT2) inhibitors, which are now standard in the adult population are being studied in pediatric population and offer new promise of pediatric heart failure treatment. Ventricular assist devices are more commonly used in cardiomyopathy patients and single ventricle patients as a bridge to transplant. Recent pediatric heart transplant society (PHTS) data demonstrated that waitlist survival improved significantly over the past decades (i) and new treatments such as daratumumab and eculizumab have been used in high-risk populations and demonstrate promising results. TEAMMATE trial is the first multicenter randomized clinical trial (RCT) in pediatric heart transplant (HT) to evaluate the safety and efficacy of everolimus (EVL) and low-dose tacrolimus (TAC) compared to standard-dose TAC and mycophenolate mofetil (MMF). It will provide valuable information about the safety and efficacy of EVL, TAC, and MMF (ii).Donor cell-free DNA has been used more in pediatric transplant recipients and has significantly decreased invasive EMB (iii). SUMMARY: This past 5 years have witness dramatic progress in the field of pediatric heart failure and transplantation including more use of mechanical support in heart failure patients with various underlying etiology, especially use of mechanical support in single ventricle patients and the use of sacubitril/valsartan and SGLT2 inhibitors in the pediatric population. The problem of the highly sensitized transplant recipient remains, although novel therapeutics have been added to our toolbox of options to maintain healthy allograft function. Ongoing research aims to further enhance our understanding and management of pediatric heart failure, emphasizing the need for continued innovation in this complex field.

Reducing donor acceptance practice variation - Learnings from a discussion forum.

PURPOSE: Although waitlist mortality is unacceptably high, nearly half of donor heart offers are rejected by pediatric heart transplant centers. The Advanced Cardiac Therapy Improving Outcome Network (ACTION) and Pediatric Heart Transplant Society (PHTS) convened a multi-institutional donor decision discussion forum (DDDF) aimed at assessing donor acceptance practices and reducing practice variation. METHODS: A 1-h-long virtual DDDF for providers across North America, the United Kingdom, and Brazil was held monthly. Each session typically included two case presentations posing a real-world donor decision challenge. Attendees were polled before the presenting center's decision was revealed. Group discussion followed, including a review of relevant literature and PHTS data. Metrics of participation, participant agreement with presenting center decisions, and impact on future decision-making were collected and analyzed. RESULTS: Over 2 years, 41 cases were discussed. Approximately 50 clinicians attended each call. Risk factors influencing decision-making included donor quality (10), size discrepancy (8), and COVID-19 (8). Donor characteristics influenced 63% of decisions, recipient factors 35%. Participants agreed with the decision made by the presenting center only 49% of the time. Post-presentation discussion resulted in 25% of participants changing their original decision. Survey conducted reported that 50% respondents changed their donor acceptance practices. CONCLUSION: DDDF identified significant variation in pediatric donor decision-making among centers. DDDF may be an effective format to reduce practice variation, provide education to decision-makers, and ultimately increase donor utilization.

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

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

Evaluating threshold for donor fraction cell-free DNA using clinically available assay for rejection in pediatric and adult heart transplantation.

BACKGROUND: The aims of the study were to assess the performance of a clinically available cell-free DNA (cfDNA) assay in a large cohort of pediatric and adult heart transplant recipients and to evaluate performance at specific cut points in detection of rejection. METHODS: Observational, non-interventional, prospective study enrolled pediatric and adult heart transplant recipients from seven centers. Biopsy-associated plasma samples were used for cfDNA measurements. Pre-determined cut points were tested for analytic performance. RESULTS: A total of 487 samples from 160 subjects were used for the analysis. There were significant differences for df-cfDNA values between rejection [0.21% (IQR 0.12-0.69)] and healthy samples [0.05% (IQR 0.01-0.14), p < .0001]. The pediatric rejection group had a median df-cfDNA value of 0.93% (IQR 0.28-2.84) compared to 0.09% (IQR 0.04-0.23) for healthy samples, p = .005. Overall negative predictive value was 0.94 while it was 0.99 for pediatric patients. Cut points of 0.13% and 0.15% were tested for various types of rejection profiles and were appropriate to rule out rejection. CONCLUSION: The study suggests that pediatric patients with rejection show higher levels of circulating df-cfDNA compared to adults and supports the specific cut points for clinical use in pediatric and adult patients with overall acceptable performance.

Demonstrating responsiveness of the pediatric cardiac quality of life inventory in children and adolescents undergoing arrhythmia ablation, heart transplantation, and valve surgery.

PURPOSE: Pediatric Cardiac Quality of Life Inventory (PCQLI) is a disease-specific pediatric cardiac health-related quality of life (HRQOL) instrument that is reliable, valid, and generalizable. We aim to demonstrate PCQLI responsiveness in children undergoing arrhythmia ablation, heart transplantation, and valve surgery before and after cardiac intervention. METHODS: Pediatric cardiac patients 8-18 years of age from 11 centers undergoing arrhythmia ablation, heart transplantation, or valve surgery were enrolled. Patient and parent-proxy PCQLI Total, Disease Impact and Psychosocial Impact subscale scores were assessed pre- and 3-12 months follow-up. Patient clinical status was assessed by a clinician post-procedure and dichotomized into markedly improved/improved and no change/worse/much worse. Paired t-tests examined change over time. RESULTS: We included 195 patient/parent-proxies: 12.6 ± 3.0 years of age; median follow-up time 6.7 (IQR = 5.3-8.2) months; procedural groups - 79 (41%) ablation, 28 (14%) heart transplantation, 88 (45%) valve surgery; clinical status - 164 (84%) markedly improved/improved, 31 (16%) no change/worse/much worse. PCQLI patient and parent-proxies Total scores increased (p ≤ 0.013) in each intervention group. All PCQLI scores were higher (p < 0.001) in the markedly improved/improved group and there were no clinically significant differences in the PCQLI scores in the no difference/worse/much worse group. CONCLUSION: The PCQLI is responsive in the pediatric cardiac population. Patients with improved clinical status and their parent-proxies reported increased HRQOL after the procedure. Patients with no improvement in clinical status and their parent-proxies reported no change in HRQOL. PCQLI may be used as a patient-reported outcome measure for longitudinal follow-up and interventional trials to assess HRQOL impact from patient and parent-proxy perspectives.

It is important to have quality of life (QOL) measures that are sensitive to change in QOL before and after procedures and to be sensitive to change over time. The Pediatric Cardiac Quality of Life Inventory (PCQLI) is a QOL measure specifically developed for children with cardiac disease. This study assessed the responsiveness of the PCQLI to detect change in QOL over time. QOL in Children and adolescents who were being treated for abnormal heart rhythms, heart transplantation, and aortic, pulmonary, or mitral valve surgery were assessed before and after their procedure. Children and adolescents with improved clinical status post-procedure, and their parents, reported better QOL after the procedure. Patients with no improvement from a cardiac standpoint and their parents reported no change in QOL after their procedure. The PCQLI may be used to assess QOL before and after cardiac procedures or medical treatment and follow QOL over time.

Association of post-operative ICU requirements with early extubation in the fontan procedure.

OBJECTIVES: This study investigated the association between early extubation (EE) and the degree of postoperative intensive care unit (ICU) support after the Fontan procedure, specifically evaluating the volume of postoperative intravenous fluid (IVF) and vasoactive-inotropic score (VIS). METHODS: Retrospective analysis of patients who underwent Fontan palliation from 2008 to 2018 at a single center was completed. Patients were initially divided into pre-institutional initiative towards EE (control) and post-initiative (modern) cohorts. Differences between the cohorts were assessed using t-test, Wilcoxon, or chi-Square. Following stratification by early or late extubation, four groups were compared via ANOVA or Kruskal-Wallis Test. RESULTS: There was a significant difference in the rate of EE between the control and modern cohorts (mean 42.6 versus 75.7%, p = 0.01). The modern cohort demonstrated lower median VIS (5 versus 8, p = 0.002), but higher total mean IVF (101±42 versus 82 ±27 cc/kg, p < 0.001) versus control cohort. Late extubated (LE) patients in the modern cohort had the highest VIS and IVF requirements. This group received 67% more IVF (140 ± 53 versus 84 ± 26 cc/kg, p < 0.001) and had a higher median VIS at 24 hours (10 (IQR, 5-10) versus 4 (IQR, 2-7), p < 0.001) versus all other groups. In comparison, all EE patients had a 5-point lower median VIS when compared to LE patients (3 versus 8, p= 0.001). CONCLUSIONS: EE following the Fontan procedure is associated with reduced post-operative VIS. LE patients in the modern cohort received more IVF, potentially identifying a high-risk subgroup of Fontan patients deserving of further investigation.

Iron Deficiency in Chronic Pediatric Heart Failure: Overall Assessment and Outcomes in Dilated Cardiomyopathy.

OBJECTIVE: To evaluate the frequency of iron status assessment in pediatric heart failure and the prevalence and adverse effects of absolute iron deficiency in dilated cardiomyopathy-induced heart failure. STUDY DESIGN: We retrospectively reviewed records of children with chronic heart failure at our center between 2010 and 2020. In children with dilated cardiomyopathy, we analyzed baseline cardiac function, hemoglobin level, and subsequent risk of composite adverse events (CAE), including death, heart transplant, ventricular assist device (VAD) placement, and transplant registry listing. Absolute iron deficiency and iron sufficiency were defined as transferrin saturations <20% and ≥30%, respectively; and indeterminant iron status as 20%-29%. RESULTS: Of 799 patients with chronic heart failure, 471 (59%) had no iron-related laboratory measurements. Of 68 children with dilated cardiomyopathy, baseline transferrin saturation, and quantitative left ventricular ejection fraction (LVEF), 33 (49%) and 14 (21%) were iron deficient and sufficient, respectively, and 21 (31%) indeterminant. LVEF was reduced to 23.6 ± 12.1% from 32.9 ± 16.8% in iron deficiency and sufficiency, respectively (P = .04), without a significant difference in hemoglobin. After stratification by New York Heart Association classification, in advanced class IV, hemoglobin was reduced to 10.9 ± 1.3 g/dL vs 12.7 ± 2.0 g/dL in iron deficiency and sufficiency, respectively (P = .01), without a significant difference in LVEF. CONCLUSIONS: In this single-center study, iron deficiency was not monitored in most children with chronic heart failure. In pediatric dilated cardiomyopathy-induced heart failure, absolute iron deficiency was prevalent and associated with clinically consequential and possibly correctable decreases in cardiac function and hemoglobin concentration.

Immune cell function assay and T lymphocyte counts lack association with rejection or infection in pediatric heart transplant recipients.

INTRODUCTION: Immune cell function assay (ICFA) and CD3 lymphocyte counts have been considered to be useful in discerning the overall intensity of immunosuppression in pediatric orthotopic heart transplant (OHT) recipients. METHODS: The aim of this retrospective analysis was to evaluate trends of ICFA and CD3 lymphocyte counts and their association with adverse outcomes post-OHT. RESULTS: A total of 381 ICFA and 493 CD3 laboratory values obtained in 78 patients within six months post-OHT were analyzed. There were 14 patients treated for biopsy-proven acute rejection, four of whom had ISHLT grade 2R/3A rejection. In patients with rejection versus those without, CD3 and ICFA values were 122 (IQR 74.5-308) cells/mm2 and 224.5 (IQR 132-343.5) ng/ml compared to 231.8 (IQR 68-421) cells/m2 and 191 (IQR 81.5-333) ng/mL (p = NS for both). Twenty-six patients had at least one detectable cytomegalovirus or Epstein-Barr virus DNAemia within the study timeframe. In patients with viremia versus those without, CD3 and ICFA values were 278.5 (IQR 68-552) cells/mm2 and 130 (IQR 48-284) ng/ml compared to 195 (IQR 74.5-402.5) cells/mm2 and 212 (IQR 89-342) ng/ml (p = NS for both). CONCLUSIONS: No association was found between these immune markers and adverse outcomes. In the absence of larger pediatric studies justifying the role of these tests in identifying elevated risk profiles post OHT, we do not recommend their routine use.

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

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

The Fontan Udenafil Exercise Longitudinal Trial: Subgroup Analysis.

The Pediatric Heart Network's Fontan Udenafil Exercise Longitudinal (FUEL) Trial (Mezzion Pharma Co. Ltd., NCT02741115) demonstrated improvements in some measures of exercise capacity and in the myocardial performance index following 6 months of treatment with udenafil (87.5 mg twice daily). In this post hoc analysis, we evaluate whether subgroups within the population experienced a differential effect on exercise performance in response to treatment. The effect of udenafil on exercise was evaluated within subgroups defined by baseline characteristics, including peak oxygen consumption (VO2), serum brain-type natriuretic peptide level, weight, race, gender, and ventricular morphology. Differences among subgroups were evaluated using ANCOVA modeling with fixed factors for treatment arm and subgroup and the interaction between treatment arm and subgroup. Within-subgroup analyses demonstrated trends toward quantitative improvements in peak VO2, work rate at the ventilatory anaerobic threshold (VAT), VO2 at VAT, and ventilatory efficiency (VE/VCO2) for those randomized to udenafil compared to placebo in nearly all subgroups. There was no identified differential response to udenafil based on baseline peak VO2, baseline BNP level, weight, race and ethnicity, gender, or ventricular morphology, although participants in the lowest tertile of baseline peak VO2 trended toward larger improvements. The absence of a differential response across subgroups in response to treatment with udenafil suggests that the treatment benefit may not be restricted to specific sub-populations. Further work is warranted to confirm the potential benefit of udenafil and to evaluate the long-term tolerability and safety of treatment and to determine the impact of udenafil on the development of other morbidities related to the Fontan circulation.Trial Registration NCT0274115.

A multi-site survey of providers on the management of heart failure with dilated cardiomyopathy in children.

We conducted a scientific survey of paediatric practitioners who manage heart failure with dilated cardiomyopathy in children. The survey covered management from diagnosis to treatment to monitoring, totalling 63 questions. There were 54 respondents from 40 institutions and 3 countries. There were diverse selections of management options by the respondents in general, but also unanimity in some management options. Variation in practice is likely due to the relative paucity of scientific data in this field and lack of strong evidence-based recommendations from guidelines, which presents an opportunity for future research and quality improvement efforts as the evidence base continues to grow.

Increase in nuclear cell-free DNA is associated with major adverse events in adult and pediatric heart transplant recipients.

BACKGROUND: Cell-free DNA is an emerging biomarker. While donor fraction may detect graft events in heart transplant recipients, the prognostic value of total nuclear cell-free DNA (ncfDNA) itself is largely unexplored. OBJECTIVE: Explore the relationship between ncfDNA and clinical events in heart transplant recipients. METHODS: We conducted a multi-center prospective study to investigate the value of cell-free DNA in non-invasive monitoring following heart transplantation. Over 4000 blood samples were collected from 388 heart transplant patients. Total ncfDNA and donor fraction were quantified. Generalized linear models with maximum likelihood estimation for repeated measures with subjects as clusters were used to explore the relationship of ncfDNA and major adverse events. Receiver operating characteristic curves were used to help choose cutpoints. RESULTS: A ncfDNA threshold (50 ng/ml) was identified that was associated with increased risk of major adverse events. NcfDNA was elevated in patients who suffered cardiac arrest, required mechanical circulatory support or died post heart transplantation as well as in patients undergoing treatment for infection. CONCLUSIONS: Elevated ncfDNA correlates with risk for major adverse events in adult and pediatric heart transplant recipients and may indicate a need for enhanced surveillance after transplant.

Association between homograft tissue exposure and allosensitization prior to heart transplant in patients with congenital heart disease.

BACKGROUND: Surgical repair for patients with congenital heart disease (CHD) often incorporates homograft tissue or other foreign material that can lead to allosensitization. We sought to identify the relationship between pre-sensitization prior to heart transplant and exposure to homograft tissue in CHD patients. METHODS: Retrospective chart review of all CHD patients who underwent heart transplant at a major pediatric transplant center between 1/1/2011-3/31/18. Operative records determined use of homograft tissue or foreign material. Panel reactive antibody (PRA) and LuminexTM single-antigen bead (SAB) testing results were reviewed. Statistical analysis determined odds of pre-sensitization in patients exposed to homograft tissue. RESULTS: Fifty-six CHD patients underwent transplant during the review period. Thirteen patients (23%) were pre-sensitized by PRA>10%. By SAB testing, 33 patients (59%) developed any anti-HLA antibody >0 MFI, 30 patients (54%) >2000 MFI, and 19 patients (34%) >6000 MFI. Patients with homografts were more likely to be pre-sensitized by PRA (OR = 7.31, p = .007), and to have developed any anti-HLA antibody at various levels, >0 (OR = 4.52, p = .034), >2000 (OR = 8.59, p = .003), and >6000 (OR = 8.50, p = .004). Of patients with homografts, those pre-sensitized by PRA had longer exposure times (9.80 vs 4.96 years, p = .025). There was no difference in exposure time with relation to pre-sensitization by SAB testing. CONCLUSIONS: Previous exposure to homograft tissue appears to increase the odds of pre-sensitization by either the PRA or SAB testing. Longer exposure time to homograft tissue prior to transplant is associated with increased pre-sensitization at transplant as determined by PRA, though not by SAB testing.

Quality of life and lifetime achievement in adult survivors of pediatric heart transplant.

BACKGROUND: Survival in pediatric heart transplantation has improved since the first successful transplant over 35 years ago leading to increasing numbers of patients entering adulthood. We sought to examine quality of life and various lifetime achievements in our institutional population of long-term adult survivors of pediatric heart transplant. METHODS: Participants ≥18 years of age who received a heart transplant as a pediatric patient (<18 years old), and who have survived ≥10 years post-transplant, completed two self-report surveys: (1) Ferrans and Powers QLI cardiac version which reports a measure of life satisfaction with a range of 0 (very dissatisfied) to 1 (very satisfied); and (2) CHONY Pediatric Heart Transplant Life Achievement Survey to examine lifetime achievement. RESULTS: Sixty-two and sixty-five participants completed the Ferrans and Powers QLI cardiac version and CHONY Pediatric Heart Transplant Life Achievement Survey. The mean overall QLI was 0.75 ± 0.14 with the most satisfaction in the family domain. QLI scores were analyzed by age at initial transplant, gender, indication for transplant, and whether patients currently followed by pediatric or adult providers, with no statistically significant differences noted. Seventy-two percent of participants demonstrated stable employment or schooling. Around thirty percent of participants showed the ability to reach academic milestones including college and post-graduate education and ten percent to start their own families. CONCLUSIONS: Our cohort of long-term adult survivors of pediatric heart transplant report a quality of life with scores thought to be reflective of a satisfactory quality of life, and many demonstrate achievement of major life milestones.

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

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

Relationship between donor fraction cell-free DNA and clinical rejection in heart transplantation.

BACKGROUND: Clinical rejection (CR) defined as decision to treat clinically suspected rejection with change in immunotherapy based on clinical presentation with or without diagnostic biopsy findings is an important part of care in heart transplantation. We sought to assess the utility of donor fraction cell-free DNA (DF cfDNA) in CR and the utility of serial DF cfDNA in CR patients in predicting outcomes of clinical interest. METHODS: Patients with heart transplantation were enrolled in two sequential, multi-center, prospective observational studies. Blood samples were collected for surveillance or clinical events. Clinicians were blinded to the results of DF cfDNA. RESULTS: A total of 835 samples from 269 subjects (57% pediatric) were included for this analysis, including 28 samples associated with CR were analyzed. Median DF cfDNA was 0.43 (IQR 0.15, 1.36)% for CR and 0.10 (IQR 0.07, 0.16)% for healthy controls (p < .0001). At cutoff value of 0.13%, the area under curve (AUC) was 0.82, sensitivity of 0.86, specificity of 0.67, and negative predictive value of 0.99. There was serial decline in DF cfDNA post-therapy, however, those with cardiovascular events (cardiac arrest, need for mechanical support or death) showed significantly higher levels of DF cfDNA on Day 0 (2.11 vs 0.31%) and Day 14 (0.51 vs 0.22%) compared to those who did not have such an event (p < .0001). CONCLUSION: DF cfDNA has excellent agreement with clinical rejection and, importantly, serial measurement of DF cfDNA predict clinically significant outcomes post treatment for rejection in these patients.

Results of the FUEL Trial.

BACKGROUND: The Fontan operation creates a total cavopulmonary connection, a circulation in which the importance of pulmonary vascular resistance is magnified. Over time, this circulation leads to deterioration of cardiovascular efficiency associated with a decline in exercise performance. Rigorous clinical trials aimed at improving physiology and guiding pharmacotherapy are lacking. METHODS: The FUEL trial (Fontan Udenafil Exercise Longitudinal) was a phase III clinical trial conducted at 30 centers. Participants were randomly assigned udenafil, 87.5 mg twice daily, or placebo in a 1:1 ratio. The primary outcome was the between-group difference in change in oxygen consumption at peak exercise. Secondary outcomes included between-group differences in changes in submaximal exercise at the ventilatory anaerobic threshold, the myocardial performance index, the natural log of the reactive hyperemia index, and serum brain-type natriuretic peptide. RESULTS: Between 2017 and 2019, 30 clinical sites in North America and the Republic of Korea randomly assigned 400 participants with Fontan physiology. The mean age at randomization was 15.5±2 years; 60% of participants were male, and 81% were white. All 400 participants were included in the primary analysis with imputation of the 26-week end point for 21 participants with missing data (11 randomly assigned to udenafil and 10 to placebo). Among randomly assigned participants, peak oxygen consumption increased by 44±245 mL/min (2.8%) in the udenafil group and declined by 3.7±228 mL/min (-0.2%) in the placebo group (P=0.071). Analysis at ventilatory anaerobic threshold demonstrated improvements in the udenafil group versus the placebo group in oxygen consumption (+33±185 [3.2%] versus -9±193 [-0.9%] mL/min, P=0.012), ventilatory equivalents of carbon dioxide (-0.8 versus -0.06, P=0.014), and work rate (+3.8 versus +0.34 W, P=0.021). There was no difference in change of myocardial performance index, the natural log of the reactive hyperemia index, or serum brain-type natriuretic peptide level. CONCLUSIONS: In the FUEL trial, treatment with udenafil (87.5 mg twice daily) was not associated with an improvement in oxygen consumption at peak exercise but was associated with improvements in multiple measures of exercise performance at the ventilatory anaerobic threshold. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02741115.