The Child Opportunity Index 2.0 and Disparities in Pediatric Cardiorespiratory Fitness.

OBJECTIVE: To evaluate the effect of neighborhood-level characteristics on cardiorespiratory fitness (CRF) via peak oxygen consumption (VO2peak) for healthy pediatric patients. STUDY DESIGN: The institutional cardiopulmonary exercise testing (CPET) database was analyzed retrospectively. All patients aged ≤ 18 years without a diagnosis of cardiac disease and with a maximal effort CPET were included. Patients were divided into three self-identified racial categories: White, Black, and Latinx. The Child Opportunity Index (COI) 2.0 was used to analyze social determinants of health. CRF was evaluated based on COI quintiles and race. Assessment of the effect of COI on racial disparities in CRF was performed using ANCOVA. RESULTS: A total of 1753 CPETs met inclusion criteria. The mean VO2peak was 42.1 ± 9.8 mL/kg/min. The VO2peak increased from 39.1 ± 9.6 mL/kg/min for patients in the very low opportunity cohort to 43.9 ± 9.4 mL/kg/min for patients in the very high opportunity cohort. White patients had higher percent predicted VO2peak compared with both Black and Latinx patients (P < .01 for both comparisons). The racial differences in CRF were no longer significant when adjusting for COI. CONCLUSION: In a large pediatric cohort, COI was associated with CRF. Racial disparities in CRF are reduced when accounting for modifiable risk factors.

Reference Values for Cardiorespiratory Fitness in Patients Aged 6 to 18 Years.

OBJECTIVE: To develop reference values for cardiorespiratory fitness, as quantified by peak oxygen uptake (VO2peak) and treadmill time, in patients aged 6 through 18 years referred for cardiopulmonary exercise testing (CPET). STUDY DESIGN: We reviewed a clinical pediatric CPET database for fitness data in children aged 6-18 years with no underlying heart disease. CPET was obtained via the Bruce protocol utilizing objectively confirmed maximal effort via respiratory exchange ratio. Fitness data (VO2peak and treadmill test duration) were analyzed to determine age- and sex-specific reference values for this pediatric cohort. RESULTS: Data from 2025 pediatric CPETs (53.2% female) were included in the analyses. VO2peak increased with age in males, but not females. Treadmill test duration increased with age in both males and females. Fitness was generally higher in males when compared with females in the same age groups. CONCLUSIONS: Our study provides extensive reference values for both VO2peak and total treadmill test time via the Bruce protocol for a pediatric population without known cardiac disease. Furthermore, the inclusion of objectively confirmed maximal exercise effort increases confidence in these findings compared with prior studies in this area. Clinicians performing CPET in pediatric populations can utilize these reference values to characterize test results according to representative peer data.

Effect of body mass index on exercise capacity following pediatric heart transplantation.

BACKGROUND: Obesity and impaired exercise tolerance following heart transplantation increase the risk of post-transplant morbidity and mortality. The aim of this study was to evaluate the effect of body mass index on markers of exercise capacity in pediatric heart transplant recipients and compare this effect with a healthy pediatric cohort. METHODS: A retrospective analysis of cardiopulmonary exercise test data between 2004 and 2022 was performed. All patients exercised on a treadmill using the Bruce protocol. Inclusion criteria included patients aged 6-21 years, history of heart transplantation (transplant cohort) or no cardiac diagnosis (control cohort) at the time of testing, and a maximal effort test. Patients were further stratified within these two cohorts as underweight, normal, overweight, and obese based on body mass index groups. Two-way analyses of variance were performed with diagnosis and body mass index category as the independent variables. RESULTS: A total of 250 exercise tests following heart transplant and 1963 exercise tests of healthy patients were included. Heart transplant patients across all body mass index groups had higher resting heart rate and lower maximal heart rate, heart rate recovery at 1 min, exercise duration, and peak aerobic capacity (VO2peak). Heart transplant patients in the normal and overweight body mass index categories had higher VO2peak and exercise duration when compared to underweight and obese patients. CONCLUSION: Underweight status and obesity are strongly associated with lower VO2peak and exercise duration in heart transplant patients. Normal and overweight heart transplant patients had the best markers of exercise capacity.

Chronotropic Response to Exercise is Decreased in Patients With Congenital Heart Disease Compared to Cardiomyopathy Following Pediatric Heart Transplantation.

BACKGROUND: Two common indications for pediatric heart transplantation are congenital heart disease and cardiomyopathy. Prior studies suggest differences in chronotropy on cardiopulmonary exercise testing outcomes depending on indication for heart transplantation. We aimed to determine whether the number of pretransplant sternotomies is associated with differences in heart rate response during exercise testing. METHODS: A retrospective analysis of our institutional pediatric heart transplant data between 2004 and 2022 was performed. Patients were categorized by indication for transplantation into a cardiomyopathy (CM) group if they had a congenital or acquired cardiomyopathy or a congenital heart disease (CHD) group including all other forms of congenital cardiac anatomic abnormalities. RESULTS: CHD patients (n = 40) differed from CM patients (n = 53) by mean number of sternotomies prior to transplant (2.4 ± 1.8 vs. 0.5 ± 0.9, p < 0.001). There were no significant differences in echocardiographic function or catheterization hemodynamics. In cardiopulmonary exercise testing performance, the congenital heart disease group had a significantly higher resting heart rate (91.8 ± 11.2 vs. 86.4 ± 10.2 bpm, p = 0.019), lower percent predicted age-predicted maximal heart rate achieved (78.3 ± 8.5% vs. 83.2 ± 11.4%, p = 0.032), and lower heart rate reserve (68.6 ± 19.8 vs. 84.4 ± 24.0 bpm, p = 0.001) despite a similar age and average time from transplantation. Regression analysis confirmed number of pretransplant sternotomies as a main predictor of heart rate metrics. CONCLUSIONS: There is greater chronotropic incompetence in patients who underwent transplantation due to congenital heart disease compared to cardiomyopathy. The groups differ significantly by number of sternotomies, potentially supporting the hypothesis that prior surgical disruption of cardiac innervation may cause decreased chronotropic response to exercise following transplantation.

Common atrial reservoir strain during the interstage period is a predictor of poor outcomes prior to Fontan completion in hypoplastic left heart syndrome.

BACKGROUND: The atrium augments ventricular function, but the significance of atrial function in hypoplastic left heart syndrome (HLHS) has not been well evaluated. OBJECTIVE: We investigated the association of atrial reservoir strain (common atrial strain [CAS]) to death or need for transplantation in patients with HLHS. METHODS: In this retrospective single-center study, echocardiograms from three timepoints (pre-stage 1 palliation [S1P], 4-8 weeks post-S1P, and pre-Glenn) were analyzed in infants with classic HLHS. Patients were separated based on transplant-free survival to Fontan (survivors) versus death or heart transplant prior to Fontan (composite outcome). Echocardiographic parameters evaluated included CAS, right ventricle (RV) global longitudinal strain (RVGLS), RV fractional area change (FAC), and tricuspid annular plane systolic excursion (TAPSE). An equal variance t-test, regression, and receiver operating characteristic (ROC) analyses were performed. RESULTS: A total of 45 HLHS patients (25 survivors, 20 patients meeting endpoint) were included in this study. There were no significant differences in any of the functional parameters during the pre-stage 1 or post-stage 1 timepoints. Pre-Glenn CAS and RVGLS were significantly worse in those meeting composite endpoint compared to survivors. CAS was significantly correlated to RVGLS during the pre-S1P and pre-Glenn timepoints. A pre-Glenn CAS < 19.5 had an area under the curve of  .78 and a 75% sensitivity and 83% specificity for death or need for transplantation. CONCLUSION: Pre-Glenn CAS is significantly lower in patients with mortality or need for the transplantation prior to Fontan completion and may carry prognostic significance in patients with HLHS.

Indication for Pediatric Heart Transplant Affects Longitudinal Chronotropy on Cardiopulmonary Exercise Testing.

Studies have suggested that pediatric patients with heart transplants (HT) due to congenital heart disease (CHD) perform differently on cardiopulmonary exercise testing compared to pediatric patients with HT due to cardiomyopathy (CM). However, it is not known if this relationship changes over time. The aim of this study was to examine the differences in cardiopulmonary exercise test (CPET) parameters over time between patients with HT due to CHD versus CM. A large single-institution CPET database was used for this study. We conducted a retrospective cohort study of 250 total CPETs from 93 unique patients, examining how patients with HT due to CHD (109 CPETs, 40 unique patients) differed in CPET performance from patients with HT due to CM (141 CPETs, 53 unique patients) from < 2 years post-HT, 2 to < 6 years post-HT, and ≥ 6 years post-HT. There were no differences between patients with HT due to CHD compared to CM in CPETs performed < 2 years post-HT. In CPETs performed 2 to < 6 years post-HT, the CM group had higher maximal HR and percentage of age-predicted maximal heart rate (APMHR) achieved. At ≥ 6 years post-HT, the CM group continued to have higher maximal HR and percentage of APMHR achieved, but also improved HR recovery at one minute. Initial indication for transplant may affect performance on CPETs post-transplant. Patients with HT due to CM have improved chronotropic measures compared to patients with HT due to CHD and these differences are more pronounced with increased time post-HT.

Prognostic Value of RV Function Analysis During the Interstage Period in Patients with Hypoplastic Left Heart Syndrome.

Cardiac dysfunction is associated with mortality in children with hypoplastic left heart syndrome (HLHS). We evaluated the ability of qualitative and quantitative RV functional parameters to predict outcomes in HLHS patients. In this retrospective, single-center study, echocardiograms from 3 timepoints (pre-stage 1 palliation, 4-8 weeks post-stage 1 palliation, and pre-Glenn) were analyzed in infants with HLHS. Patients were stratified into two groups based on outcome of transplant-free survival post-Glenn (survivors) versus mortality or transplantation prior to Fontan (non-survivors). Images were retrospectively reviewed to obtain RV global longitudinal strain (RVGLS), RV-free wall strain (RVFWS), fractional area change (FAC), tricuspid annular systolic plane excursion (TAPSE), tissue motion annular displacement of the tricuspid valve (TMAD-TV) and qualitative systolic function assessment during the predetermined timepoints. An equal variance t-test and chi-square were used to determine significant differences and ROC curve analysis was performed to derive optimal cutoff values to predict mortality/transplant. A total of 47 patients met inclusion criteria, of which, 21 patients met composite endpoint. There were no significant differences in any RV functional parameter during the pre- or post-stage 1 palliation timepoints. The absolute values of RVFWS, RVGLS, and TMAD-TV were significantly greater in survivors than non-survivors during the pre-Glenn timepoint. A pre-Glenn RVGLS > -15.6 (AUC 0.79), RVFWS > -18.6 (AUC 0.75), and TMAD-TV < 12.6% (AUC 0.82) were sensitive and specific for predicting death or need for transplantation prior to Fontan completion. RVGLS, RVFWS, and TMAD-TV may help identify higher-risk HLHS patients during the interstage period.

High-Sensitivity Troponin T Testing for Pediatric Patients in the Emergency Department.

Debate exists on the usefulness of high-sensitivity cardiac troponin (hs-cTn) testing in pediatric patients due to the perceived low incidence of myocardial injury and lack of data concerning its efficacy. We evaluated the contribution of an increased hs-cTnT above the 99th percentile upper-reference limit (URL) to clinical diagnoses made in pediatric patients presenting to the emergency department (ED). Retrospective cohort study including patients aged 0-18 years presenting to the ED from 2018 to 2020 where hs-cTnT was measured. Sex-specific 99th percentile URLs of 15 and 10 ng/L for males and females, respectively, were used, with concentrations above these thresholds considered indicative of myocardial injury. Overall, 356 patients were identified in whom hs-cTnT concentrations were measured during ED clinical evaluation. Hs-cTnT was increased above the 99th percentile on presentation in 36 patients (10.1%). Twelve patients (3.4%) had a clinical cardiac diagnosis made. Hs-cTnT was increased in 6 of these (50.0%). Serial hs-cTnT from 106 patients with an initial hs-cTnT < 99th percentile was subsequently elevated in 5 (4.6%); none of whom had a final clinical cardiac diagnosis. Hs-cTnT has high specificity, but low sensitivity when used as a screening tool for myocardial injury when the gold standard is mostly clinical assessment. In present practice, however, they do not appear to track well with clinical diagnoses. Further studies are needed to more clearly define the role of hs-cTnT in this patient population.

Ventriculotomy Decreases Agreement Between Assessment of Right Ventricular Function by Echocardiography and Cardiac Magnetic Resonance Imaging in Patients with Hypoplastic Left Heart Syndrome.

Accurate assessment of the right ventricular (RV) volume and function is important in patients with hypoplastic left heart syndrome (HLHS). We sought to investigate the effect of ventriculotomy on the correlation of RV functional assessments by two-dimensional echocardiography (2DE) to cardiac magnetic resonance (CMR)-derived RV ejection fraction (EF) in patients with HLHS. A retrospective re-analysis of CMR imaging with matched 2DE was performed from the institutional HLHS registry. Echocardiographic RV functional parameters were analyzed and correlated with CMR-derived EF. Intraclass correlation coefficient was used to determine interobserver reliability. A total of 58 matched echocardiograms and CMR imaging studies from 46 patients was evaluated. Median duration between CMR imaging and echocardiogram was 1 day (range 0-6 days). No significant difference was seen in CMR RV EF between patients with and without a ventriculotomy (EF - 43.6% vs 44.7%, p = 0.85). The presence of a ventriculotomy significantly decreased the correlation of biplane FAC (r = 0.86 vs 0.52; p = 0.02), triplane FAC (r = 0.84 vs 0.49; p = 0.03), and 2DE visually estimated EF (r = 0.83 vs 0.49; p = 0.02). The correlation of circumferential and longitudinal strains to CMR-derived EF was not significantly affected by the presence of a ventriculotomy. A prior ventriculotomy significantly affected correlation between 2DE FAC and visually estimated EF with CMR-derived EF. The dyskinetic myocardial segment due to ventriculotomy, which is often not visualized by 2DE, may be the reason for this discrepancy.

Negative Impact of the Left Ventricular Remnant Morphology on Systemic Right Ventricular Myocardial Deformation in Hypoplastic Left Heart Syndrome.

Left ventricular (LV) morphology may affect right ventricular (RV) function before and after Fontan palliation in patients with hypoplastic left heart syndrome (HLHS). We sought to assess the potential impact of LV morphology on RV function in patients with HLHS using cardiac magnetic resonance (CMR) imaging. A retrospective analysis of available CMR scans from all patients with HLHS was performed. LV morphology was categorized as absent/slit-like or globular/miniaturized. Volumetric analysis was performed using manual disc-summation method on steady-state free precession (SSFP) stack obtained in short-axis orientation of the ventricles. 4-chamber and short-axis SSFP images were used to measure strain on a semi-automated feature-tracking (FT) module. Two sample t-test was used to compare the groups. A total of 48 CMR scans were analyzed. Of those, 12 patients had absent/slit-like and 36 had globular/miniaturized LV morphology. Averaged 4-chamber longitudinal RV strain was significantly higher for absent/slit-like (- 17.6 ± 4.7%) than globular/miniaturized (- 13.4 ± 3.5; P = 0.002). Averaged 4-chamber radial RV strain was also significantly higher for absent/slit-like (33.1 ± 14.9%) than globular/miniaturized (21.6 ± 7.1; P = 0.001). For globular/miniaturized LV morphology, the decreases of 4-chamber longitudinal and radial strains were mainly attributable to the septal basilar and septal mid-ventricular segments. No differences were found in short-axis RV global circumferential strain between the morphologic subtypes (absent/slit-like - 15.0 ± 6.5, globular/miniaturized - 15.7 ± 4.7; P = 0.68). Larger LV remnants, with globular/miniaturized LV morphology, demonstrated diminished strain in the septal base and mid-ventricle segments. Patients with globular/miniaturized LV morphology may benefit with closer monitoring and lower threshold to start heart failure medications. These results exemplify the utility of including both septal and regional deformation in systemic RV strain analysis.

A Reference Equation for Peak Oxygen Uptake for Pediatric Patients Who Undergo Treadmill Cardiopulmonary Exercise Testing.

Pediatric patients are often referred to cardiopulmonary exercise testing (CPET) laboratories for assessment of exercise-related symptoms. For clinicians to understand results in the context of performance relative to peers, adequate fitness-based prediction equations must be available. However, reference equations for prediction of peak oxygen uptake (VO2peak) in pediatrics are largely developed from field-based testing, and equations derived from CPET are primarily developed using adult data. Our objective was to develop a pediatric reference equation for VO2peak. Clinical CPET data from a validation cohort of 1,383 pediatric patients aged 6 to 18 years who achieved a peak respiratory exchange ratio ≥1.00 were analyzed to identify clinical and exercise testing factors that contributed to the prediction of VO2peak from tests performed using the Bruce protocol. The resultant prediction equation was applied to a cross-validation cohort of 1,367 pediatric patients. Exercise duration, gender, weight, and age contributed to the prediction of VO2peak, generating the following prediction equation: (R2 = 0.645, p <0.001, standard error of the estimate = 6.19 ml/kg/min): VO2peak (ml/kg/min) =16.411+ 3.423 (exercise duration [minutes]) - 5.145 (gender [0 = male, 1 = female]) - 0.121 (weight [kg]) + 0.179 (age [years]). This equation was stable across the age range included in the present study, with differences ≤0.5 ml/kg/min between mean measured and predicted VO2peak in all age groups. In conclusion, this study represents what we believe is the largest pediatric CPET-derived VO2peak prediction effort to date, and this VO2peak prediction equation provides clinicians who perform and interpret exercise tests in pediatric patients with a resource with which to better quantify fitness when CPET is not available.

Primary Adjunctive Corticosteroids in the Acute Management of High-Risk Kawasaki Disease in a North American Cohort.

BACKGROUND: Primary adjunctive therapy with corticosteroids have been shown to reduce coronary artery abnormalities in high-risk Kawasaki Disease (KD) patients in Japan (RAISE study). We evaluated their effect on outcomes in North American patients with high-risk KD. METHODS: We performed a single-center retrospective review of high-risk KD patients between 2010 - 2023. From 2017-2023, adjunctive corticosteroids in a modified RAISE regimen (mRAISE) were given to high-risk patients as primary adjunctive therapy with intravenous gammaglobulin (IVIG) and aspirin. We compared CA outcomes in these patients and those presenting from 2010-2016, when mRAISE therapy was not administered. RESULTS: A total of 221 high-risk KD patients were treated at our institution between 2010-2023. Among these, 83 received the mRAISE regimen and 138 did not (no corticosteroid, n=82, corticosteroid in a non-mRAISE regimen, n=56). There were no significant differences in coronary artery outcomes in the mRAISE and non-mRAISE groups. Patients receiving the mRAISE regimen were significantly less likely to receive more than one dose of IVIG when compared to those who did not receive this regimen (11% vs 33%, p<0.001). CONCLUSION: Use of adjunctive primary therapy with corticosteroids in a mRAISE regimen in high-risk KD patients resulted in significantly decreased IVIG retreatment.