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.

Lower Airway Nitrogen Oxide Levels in Children with Primary Ciliary Dyskinesia Is Linked to Neutrophilic Inflammation.

Treatment of primary ciliary dyskinesia pulmonary exacerbations resulted in an increase in sputum nitric oxide (NO) metabolites and decrease in neutrophilic inflammation. The association between the 2 suggests that neutrophilic inflammation contributes to airway NO deficiency in primary ciliary dyskinesia and that reducing inflammation may lead to improved airway NO homeostasis. TRIAL REGISTRY: ClinicalTrials.gov: NCT01155115.

Lung Clearance Index to Track Acute Respiratory Events in School-Age Children with Cystic Fibrosis.

Rationale: The lung clearance index (LCI) is responsive to acute respiratory events in preschool children with cystic fibrosis (CF), but its utility to identify and manage these events in school-age children with CF is not well defined.Objectives: To describe changes in LCI with acute respiratory events in school-age children with CF.Methods: In a multisite prospective observational study, the LCI and FEV1 were measured quarterly and during acute respiratory events. Linear regression was used to compare relative changes in LCI and FEV1% predicted at acute respiratory events. Logistic regression was used to compare the odds of a significant worsening in LCI and FEV1% predicted at acute respiratory events. Generalized estimating equation models were used to account for repeated events in the same subject.Measurements and Main Results: A total of 98 children with CF were followed for 2 years. There were 265 acute respiratory events. Relative to a stable baseline measure, LCI (+8.9%; 95% confidence interval, 6.5 to 11.3) and FEV1% predicted (-6.6%; 95% confidence interval, -8.3 to -5.0) worsened with acute respiratory events. A greater proportion of events had a worsening in LCI compared with a decline in FEV1% predicted (41.7% vs. 30.0%; P = 0.012); 53.9% of events were associated with worsening in LCI or FEV1. Neither LCI nor FEV1 recovered to baseline values at the next follow-up visit.Conclusions: In school-age children with CF, the LCI is a sensitive measure to assess lung function worsening with acute respiratory events and incomplete recovery at follow-up. In combination, the LCI and FEV1 capture a higher proportion of events with functional impairment.

Determinants of lung disease progression measured by lung clearance index in children with cystic fibrosis.

The lung clearance index (LCI) measured by the multiple breath washout (MBW) test is sensitive to early lung disease in children with cystic fibrosis. While LCI worsens during the preschool years in cystic fibrosis, there is limited evidence to clarify whether this continues during the early school age years, and whether the trajectory of disease progression as measured by LCI is modifiable.A cohort of children (healthy and cystic fibrosis) previously studied for 12 months as preschoolers were followed during school age (5-10 years). LCI was measured every 3 months for a period of 24 months using the Exhalyzer D MBW nitrogen washout device. Linear mixed effects regression was used to model changes in LCI over time.A total of 582 MBW measurements in 48 healthy subjects and 845 measurements in 64 cystic fibrosis subjects were available. The majority of children with cystic fibrosis had elevated LCI at the first preschool and first school age visits (57.8% (37 out of 64)), whereas all but six had normal forced expiratory volume in 1 s (FEV1) values at the first school age visit. During school age years, the course of disease was stable (-0.02 units·year-1 (95% CI -0.14-0.10). LCI measured during preschool years, as well as the rate of LCI change during this time period, were important determinants of LCI and FEV1, at school age.Preschool LCI was a major determinant of school age LCI; these findings further support that the preschool years are critical for early intervention strategies.

Hyperpolarised 129Xe magnetic resonance imaging to monitor treatment response in children with cystic fibrosis.

Pulmonary magnetic resonance imaging using hyperpolarised 129Xe gas (XeMRI) can quantify ventilation inhomogeneity by measuring the percentage of unventilated lung volume (ventilation defect per cent (VDP)). While previous studies have demonstrated its sensitivity for detecting early cystic fibrosis (CF) lung disease, the utility of XeMRI to monitor response to therapy in CF is unknown. The aim of this study was to assess the ability of XeMRI to capture treatment response in paediatric CF patients undergoing inpatient antibiotic treatment for a pulmonary exacerbation.15 CF patients aged 8-18 years underwent XeMRI, spirometry, plethysmography and multiple-breath nitrogen washout at the beginning and end of inpatient treatment of a pulmonary exacerbation. VDP was calculated from XeMRI images obtained during a static breath hold using semi-automated k-means clustering and linear binning approaches.XeMRI was well tolerated. VDP, lung clearance index and the forced expiratory volume in 1 s all improved with treatment; however, response was not uniform in individual patients. Of all outcome measures, VDP showed the largest relative improvement (-42.1%, 95% CI -52.1--31.9%, p<0.0001).These data support further investigation of XeMRI as a tool to capture treatment response in CF lung disease.

Renal injury and recovery in pediatric patients after ventricular assist device implantation and cardiac transplant.

BACKGROUND: The use of ventricular assist devices (VADs) in children with heart failure may be of particular benefit to those with accompanying renal failure, as improved renal function is seen in some, but not all recipients. We hypothesized that persistent renal dysfunction at 7 days and/or 1 month after VAD implantation would predict chronic kidney disease (CKD) 1 year after heart transplantation (HT). METHODS: Linkage analysis of all VAD patients enrolled in both the PEDIMACS and PHTS registries between 2012 and 2016. Persistent acute kidney injury (P-AKI), defined as a serum creatinine ≥1.5× baseline, was assessed at post-implant day 7. Estimated glomerular filtration rate (eGFR) was determined at implant, 30 days thereafter, and 12 months post-HT. Pre-implant eGFR, eGFR normalization (to ≥90 mL/min/1.73 m2 ), and P-AKI were used to predict post-HT CKD (eGFR <90 mL/min/1.73 m2 ). RESULTS: The mean implant eGFR was 85.4 ± 46.5 mL/min/1.73 m2 . P-AKI was present in 19/188 (10%). Mean eGFR at 1 month post-VAD implant was 131.1 ± 62.1 mL/min/1.73 m2 , significantly increased above baseline (P < 0.001). At 1 year post-HT (n = 133), 60 (45%) had CKD. Lower pre-implant eGFR was associated with post-HT CKD (OR 0.99, CI: 0.97-0.99, P = 0.005); P-AKI was not (OR 0.96, CI: 0.3-3.0, P = 0.9). Failure to normalize renal function 30 days after implant was highly associated with CKD at 1 year post-transplant (OR 12.5, CI 2.8-55, P = 0.003). CONCLUSIONS: Renal function improves after VAD implantation. Lower pre-implant eGFR and failure to normalize renal function during the support period are risk factors for CKD development after HT.

Healthy hearts in pediatric heart transplant patients with an exercise and diet intervention via live video conferencing-Design and rationale.

BACKGROUND: Pediatric heart transplant (PedHtx) patients have increased cardiovascular risk profiles that affect their long-term outcomes and quality of life. We designed a 12- to 16-week diet and exercise intervention delivered via live video conferencing to improve cardiovascular health. Our methodology and baseline assessment of the first 13 enrolled patients are reported. METHODS: Inclusion criteria are as follows: (a) 8-19 years old; (b) heart transplant >12 months; (c) ability to fast overnight; (d) cardiac clearance by cardiologist; and (e) presence of an adult at home during exercise sessions for patients <14 years old. Exclusion criteria are as follows: (a) acute illness; (b) latex allergy; (c) transplant rejection <3 months ago; and (d) multi-organ transplantation. The intervention consists of one diet and three exercise sessions weekly via live video conferencing. Study visits are conducted at baseline, intervention completion, and end of maintenance period. RESULTS: A total of 13 participants (15.2 [2.3] years) have been enrolled. Median percent-predicted VO2 max was 56.8 [20.7]% (10 patients <70%). Ten patients had abnormal endothelial function (reactive hyperemia index <1.9; 1.4 [0.325]) and 11 patients had stiff arteries (pulse wave velocity ≧5.5 m/s for 15-19 years, ≧4.5 m/s for 8-14 years; 5.6 [0.7] m/s). Patients had suboptimal diets (saturated fat: 22.7 [23.8] g/d, sodium: 2771 [1557] mg/d) and were sedentary at a median of 67.5 [13.8]% of their time. CONCLUSIONS: Baseline assessment confirms that PedHtx patients have abnormal cardiac, vascular, and functional health indices, poor dietary habits, and are sedentary. These results support the rationale to test the feasibility and impact of a non-pharmacologic lifestyle intervention in this patient population.

Impact of Heart Transplantation on the Functional Status of US Children With End-Stage Heart Failure.

BACKGROUND: There are limited data describing the functional status (FS) of children after heart transplant (HT). We sought to describe the FS of children surviving at least 1 year after HT, to evaluate the impact of HT on FS, and to identify factors associated with abnormal FS post-HT. METHODS: Organ Procurement and Transplantation Network data were used to identify all US children <21 years of age surviving ≥1 year post-HT from 2005 to 2014 with a functional status score (FSS) available at 3 time points (listing, transplant, ≥1 year post-HT). Logistic regression and generalized estimating equations were used to identify factors associated with abnormal FS (FSS≤8) post-HT. RESULTS: A total of 1633 children met study criteria. At the 1-year assessment, 64% were "fully active/no limitations" (FSS=10), 21% had "minor limitations with strenuous activity" (FSS=9); and 15% scored ≤8. In comparison with listing FS, FS at 1 year post-HT increased in 91% and declined/remained unchanged in 9%. A stepwise regression procedure selected the following variables for association with abnormal FS at 1 year post-HT: ≥18 years of age (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.2-2.7), black race (OR, 1.5; 95% CI, 1.1-2.0), support with ≥inotropes at HT (OR, 1.7; 95% CI, 1.2-2.5), hospitalization status at HT (OR, 1.5; 95% CI, 1.0-2.19), chronic steroid use at HT (OR, 1.5; 95% CI, 1.0-2.2), and treatment for early rejection (OR, 2.0; 95% CI, 1.5-2.7). CONCLUSION: Among US children who survive at least 1 year after HT, FS is excellent for the majority of patients. HT is associated with substantial improvement in FS for most children. Early rejection, older age, black race, chronic steroid use, hemodynamic support at HT, and being hospitalized at HT are associated with abnormal FS post-HT.

Rehospitalization after pediatric heart transplantation: Incidence, indications, and outcomes.

We report the patterns of rehospitalization after pediatric heart transplant (Htx) at a single center. Retrospective review of 107 consecutive pediatric Htx recipients between January 22, 2007, and August 28, 2014, who survived their initial transplant hospitalization. The frequency, duration, and indications for all hospitalizations between transplant hospitalization discharge and September 30, 2015, were analyzed. A total of 444 hospitalization episodes occurred in 90 of 107 (84%) patients. The median time to first rehospitalization was 59.5 (range 1-1526) days, and the median length of stay was 2.5 (range 0-81) days. There were an average of two hospitalizations per patient in the first year following transplant hospitalization, declining to about 0.8 per patient per year starting at 3 years post-transplant. Admissions for viral infections were most common, occurring in 93 of 386 (24%), followed by rule out sepsis in 61 of 386 (16%). Admissions for suspected or confirmed rejection were less frequent, accounting for 41 of 386 (11%) and 31 of 386 (8%) of all admissions, respectively. Survival to discharge after rehospitalization was 97%. Hospitalization is common after pediatric Htx, particularly in the first post-transplant year, with the most frequent indications for hospitalization being viral illness and rule out sepsis. After the first post-transplant year, the risk for readmission falls significantly but remains constant for several years.

Changes in airway inflammation during pulmonary exacerbations in patients with cystic fibrosis and primary ciliary dyskinesia.

Lung disease in patients with both primary ciliary dyskinesia (PCD) or cystic fibrosis (CF) is associated with impaired mucociliary clearance; however, clinical outcomes are typically worse in CF patients. We assessed whether CF and PCD patients differ in inflammatory response in the airways during pulmonary exacerbation.We first studied clinically stable PCD patients with a spectrum of bacterial pathogens to assess inflammatory response to different pathogens. Subsequently, PCD and CF patients with similar bacterial pathogens were studied at the time of a pulmonary exacerbation and after 21 days of antibiotics treatment. Qualitative and quantitative microbiology, cell counts, interleukin-8 concentrations, and neutrophil elastase activity were assessed in sputum samples obtained before and after treatment.In stable PCD patients, no significant differences were found in sputum inflammatory markers between individuals colonised with different bacterial pathogens. Pulmonary exacerbation severity assessed by a pulmonary exacerbation score and lung function decline from their previous baseline did not differ between CF and PCD patients. Bacterial density for Staphylococcus aureus and Haemophilus influenzae was higher in CF versus PCD (p<0.05), but absolute neutrophil counts were higher in PCD patients (p=0.02). While sputum elastase activity was similar in PCD and CF at the time of exacerbation, it decreased with antibiotic therapy in PCD (p<0.05) but not CF patients.PCD patients differ from those with CF in their responses to treatment of pulmonary exacerbations, with higher neutrophil elastase activity persisting in the CF airways at the end of treatment.

Group visits in the pediatric heart transplant outpatient clinic.

The "GVM" has emerged as an alternative to traditional individualized appointments in the ambulatory care setting. We hypothesized that group visits could successfully be utilized in a PHtx clinic. Seven patients, ages 1-18 yr old, and their families participated in a total of 11 group visits in lieu of individualized appointments. Patients were divided into two groups based on whether they were greater or less than one yr post-transplant. Patient/provider satisfaction, medication adherence, and content retention were ascertained via questionnaires and free-response tests. Total clinic throughput time, including per-patient clinic utilization time, was compared to historical data. Six of seven patients completed the study with one dropout. Overall satisfaction ratings were 3.98 of 4 with all patients reporting that they would "strongly recommend" group visits to others. Health information retention tests demonstrated improvement between pre- and post-tests in eight of nine (89%) of the group visits. Overall clinic utilization decreased by nearly 50% while providing 70 min of face-to-face time with the provider. Medication adherence neared 100% for all patients. The GVM can be successfully applied to the PHtx population with high patient and provider satisfaction, more face-to-face time, excellent content retention, and greatly improved clinic efficiency.

Feasibility of Assessing Adolescent and Young Adult Heart Transplant Recipient Mental Health and Resilience Using Patient-Reported Outcome Measures.

BACKGROUND: Although adolescents and young adults may be particularly prone to mental health symptoms after heart transplant, screening practices are variable. OBJECTIVE: To assess the feasibility of using patient-reported outcome (PRO) measures to assess mental health, functional status, and resiliency in posttransplant adolescents and young adult patients. METHODS: Patients transplanted between ages 15 and 25 years at 3 centers completed 6 PRO instruments via web-based platforms: PROMIS instruments for anxiety, depression, satisfaction with social roles, and physical functioning; the Posttraumatic Stress Diagnostic Scale for Diagnostic and Statistical Manual of Mental Disorders, version 5; and the Connor-Davidson Resilience Scale-10. Feasibility (completion, time to completion, and measure missingness) and PRO results were described and compared between patients with congenital heart disease and cardiomyopathy. RESULTS: Nineteen patients (median age at transplant 17.7 y [interquartile range 16.3, 19.2 y], 84% male) were enrolled at an average of 3 ± 1.8 years after transplant. Enrollment was 90% among eligible patients. Measure missingness was zero. The average completion time was 12 ± 15 minutes for all instruments. Timely PRO completion was facilitated by in-clinic application. The PRO results indicated that 9 patients (47%) had at least mild posttraumatic stress disorder symptoms (≥11 points on Posttraumatic Stress Diagnostic Scale for Diagnostic and Statistical Manual of Mental Disorders, version 5). Among them, 4 patients had scores >28 suggestive of probable posttraumatic stress disorder. Two (11%) and 6 (32%) patients had anxious and depressive symptoms, respectively. The cardiomyopathy cohort had a higher median Posttraumatic Stress Diagnostic Scale for Diagnostic and Statistical Manual of Mental Disorders, version 5 score than that of the congenital heart disease subgroup (11.0 vs 6.0; P = 0.015). Twelve (63%) had resiliency scores that were lower than the population average. No significant differences were found in PRO results between patients with cardiomyopathy and congenital heart disease apart from the posttraumatic stress disorder assessment. CONCLUSIONS: This novel PRO-based approach to psychiatric screening of adolescents and young adult patients after transplant appears feasible for assessing mental health, functional status, and resiliency, with excellent enrollment and completion rates. These instruments characterized the burden of mental health symptoms within this adolescents and young adult heart transplant cohort, with a high prevalence of posttraumatic stress disorder symptoms. Resiliency scores were lower than in a comparison population. Electronically-administered PRO administration could facilitate more consistent mental health screening in this at-risk group.

Pseudomonas aeruginosa aggregation and Psl expression in sputum is associated with antibiotic eradication failure in children with cystic fibrosis.

We previously demonstrated that P. aeruginosa isolates that persisted in children with cystic fibrosis (CF) despite inhaled tobramycin treatment had increased anti-Psl antibody binding in vitro compared to those successfully eradicated. We aimed to validate these findings by directly visualizing P. aeruginosa in CF sputum. This was a prospective observational study of children with CF with new-onset P. aeruginosa infection who underwent inhaled tobramycin eradication treatment. Using microbial identification passive clarity technique (MiPACT), P. aeruginosa was visualized in sputum samples obtained before treatment and classified as persistent or eradicated based on outcomes. Pre-treatment isolates were also grown as biofilms in vitro. Of 11 patients enrolled, 4 developed persistent infection and 7 eradicated infection. P. aeruginosa biovolume and the number as well as size of P. aeruginosa aggregates were greater in the sputum of those with persistent compared with eradicated infections (p < 0.01). The amount of Psl antibody binding in sputum was also greater overall (p < 0.05) in samples with increased P. aeruginosa biovolume. When visualized in sputum, P. aeruginosa had a greater biovolume, with more expressed Psl, and formed more numerous, larger aggregates in CF children who failed eradication therapy compared to those who successfully cleared their infection.

Comparison of combined heart‒liver vs heart-only transplantation in pediatric and young adult Fontan recipients.

BACKGROUND: Indications for a heart‒liver transplantation (HLT) for Fontan recipients are not well defined. We compared listing characteristics, post-operative complications, and post-transplant outcomes of Fontan recipients who underwent HLT with those of patients who underwent heart-only transplantation (HT). We hypothesized that patients who underwent HLT have increased post-operative complications but superior survival outcomes compared with patients who underwent HT. METHODS: We performed a retrospective review of Fontan recipients who underwent HLT or HT at a single institution. Characteristics at the time of listing, including the extent of liver disease determined by laboratory, imaging, and biopsy data, were compared. Post-operative complications were assessed, and the Kaplan‒Meier survival method was used to compare post-transplant survival. Univariate regression analyses were performed to identify the risk factors for increased mortality and morbidity among patients who underwent HT. RESULTS: A total of 47 patients (9 for HLT, 38 for HT) were included. Patients who underwent HLT were older, were more likely to be on dual inotrope therapy, and had evidence of worse liver disease. Whereas ischemic time was longer for the group who underwent HLT, post-operative complications were similar. Over a median post-transplant follow-up of 17 (interquartile range: 5-52) months, overall mortality for the cohort was 17%; only 1 patient who underwent HLT died (11%) vs 7 patients who underwent HT (18%) (p = 0.64). Among patients who underwent HT, cirrhosis on pre-transplant imaging was associated with worse outcomes. CONCLUSIONS: Despite greater inotrope need and more severe liver disease at the time of listing, Fontan recipients undergoing HLT have post-transplant outcomes comparable with those of patients undergoing HT. HLT may offer a survival benefit for Fontan recipients with liver disease.

Healthy Hearts via Live Videoconferencing: An Exercise and Diet Intervention in Pediatric Heart Transplant Recipients.

Background Pediatric heart transplant recipients have high-risk cardiovascular profiles that can affect their long-term outcomes; however, promoting exercise and healthy diet has not been a major focus in the field. The objective of this study was to test the feasibility and impact of a supervised exercise and diet intervention delivered via live videoconferencing in this population. Methods and Results Patients 8 to 19 years of age at least 1 year post heart transplantation were enrolled. The 12- to 16-week intervention phase included live video-supervised exercise (×3/week) and nutrition (×1/week) sessions. The 12- to 16-week maintenance phase included ×1/week live video-supervised exercise and nutrition sessions and ×2/week self-directed exercise sessions. Cardiac, vascular, nutritional, and functional health indices were obtained at baseline, after intervention, and after maintenance. Fourteen patients (median age, 15.2; interquartile range, 14.3-16.7 years) at a median of 3.3 (interquartile range, 1.5-9.7) years after heart transplant completed the intervention. Patients attended 89.6±11% of exercise and 88.4±10% of nutrition sessions during the intervention and 93.4±11% of exercise and 92.3±11% of nutrition sessions during maintenance. After intervention, body mass index percentile (median, -27%; P=0.02), endothelial function (median, +0.29; P=0.04), maximum oxygen consumption (median, +2 mL/kg per minute; P=0.002). Functional Movement Screening total score (median, +2.5; P=0.002) and daily consumption of saturated fat (median, -6 g; P=0.02) improved significantly. After maintenance, improvements in maximum oxygen consumption (median, +3.2 mL/kg per minute; P=0.02) and Functional Movement Screening total score (median, +5; P=0.002) were sustained. Conclusions In pediatric heart transplant recipients, a live video-supervised exercise and diet intervention is feasible. Our results demonstrate excellent adherence with significant improvements in cardiovascular and functional health. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT02519946.

Pilot trial of tobramycin inhalation powder in cystic fibrosis patients with chronic Burkholderia cepacia complex infection.

There is no effective chronic suppressive therapy Burkholderia cepacia complex infection in cystic fibrosis (CF) patients. This was a pilot, open-label clinical trial of tobramycin inhalation powder (TIP) delivered via Podhaler twice daily for 28days in adults and children with CF and chronic B. cepacia complex infection in Toronto, Canada. A total of 10 subjects (4 pediatric, 6 adult patients) were treated. There was a mean drop of 1.4 log (CFU/ml) in sputum bacterial density (p=0.01) and sputum IL-8 levels decreased significantly after 28days of TIP (p=0.04). The mean relative change in FEV1 (L) from Day 0 to Day 28 of TIP administration was a 4.6% increase but this was not statistically significant. The majority of patients (70%) had no or mild adverse events.