New Reference Values for Cardiopulmonary Exercise Testing in Children

Myocardial function, mechanics and work by echocardiography in adolescents with severe obesity

Introduction

Obesity and its metabolic complications can impact the heart's structure and function in childhood, although demonstrating this impact has been challenging. New echocardiographic parameters such as left atrial strain (LAε) and left ventricular strain (LVε), as well as myocardial work (MW), could reveal subclinical alterations in cardiac function.

Objective

The aim is to evaluate the feasibility of these parameters in adolescents with severe obesity and explore their associations with body fat, metabolic comorbidities, and physical capacity.

Methods

This is a cross-sectional study in adolescents with obesity who underwent echocardiography with analysis of LAε, LVε and MW using speckle tracking. Feasibility and association with anthropometry, body fat percentage, comorbidities and cardiopulmonary test were analyzed.

Results

Twenty adolescents were recruited, 13 (65%) were males, median age 14.2 (interquartile range: 12.9-14.9) years old. The median Z-score for BMI (zBMI) was +3.03 (2.87-3.14), 14 (70%) had severe obesity (zBMI ≥+3), 12 (60%) body fat ≥95th percentile, 9 (45%) high blood pressure (HBP) and 8 (40%) metabolic syndrome. The analysis of the echocardiographic parameters was feasible in 95% (LAε) and 100% (LVε and MW). LVε was lower in adolescents with vs. without metabolic syndrome: 17.8% (17.5-19.3%) vs. 19.3% (18.3-20.3%), P = 0.046; and with vs. without HBP 17.8% (17.5-18.6%) vs. 19.7% (18.4-20.3%), P = 0.02. Those with body fat ≥95th percentile had lower LAε and MW parameters, without association with cardiopulmonary test.

Conclusion

Echocardiographic evaluation of LAε, LVε and MW is feasible in adolescents with severe obesity. A higher proportion of body fat and the presence of comorbidities are associated with alterations in these new echocardiographic functional parameters suggesting myocardial impact of higher metabolic compromise.

Reduced exercise capacity for muscle mass in adolescents living with obesity

BACKGROUND

Adolescents living with obesity (AlwO) can have limited exercise capacity. Exercise capacity can be predicted by a 2-factor model comprising lung function and leg muscle function, but no study has looked at cycling leg muscle function and its contribution to cycling exercise capacity in AlwO.

METHODS

Twenty-two nonobese adolescents and 22 AlwO (BMI > 95 percentile) were studied. Anthropometry, body composition (dual-energy X-ray absorptiometry), spirometry, 30-s isokinetic work capacity, and maximal exercise (cycle ergometry) were measured.

RESULTS

AlwO had greater total body mass, lean body mass, and lean leg mass (LLM). Lung function trended higher in AlwO. Leg 30-s work did not differ in absolute terms or per allometrically scaled LLM. Peak oxygen consumption did not differ between the groups in absolute terms or as percent predicted values (79.59 ± 14.6 vs. 82.3 ± 11.2% predicted control versus ALwO) but was lower in AlwO when expressed per kg body mass, kg lean body mass, scaled lean body mass, and LLM. Peak oxygen consumption related to both lung function and 30-s work, with no observed group effect. 30-s leg work related to the scaled LLM, with a small group effect. There was some correlation between leg work and time spent in moderate to vigorous physical activity in AlwO (rs = 0.39, p = .07).

CONCLUSION

AlwO have larger LLM and preserved exercise capacity, when expressed as percentage of predicted, but not per allometrically scaled LLM. Increasing time spent in moderate to vigorous activity may benefit AlwO.

Long-term outcomes of pulmonary embolism in children and adolescents

ABSTRACT

Knowledge regarding the long-term consequences of pulmonary embolism (PE) in children is limited. This cohort study describes the long-term outcomes of PE in children who were followed-up at a single-center institution using a local protocol that included clinical evaluation, chest imaging, echocardiography, pulmonary function tests, and cardiopulmonary exercise tests at follow-up, starting 3 to 6 months after acute PE. Children objectively diagnosed with PE at age 0 to 18 years, who had ≥6 months of follow-up were included. Study outcomes consisted of PE resolution, PE recurrence, death, and functional outcomes (dyspnea, impaired pulmonary or cardiac function, impaired aerobic capacity, and post-PE syndrome). The frequency of outcomes was compared between patients with/without underlying conditions. In total, 150 patients were included; median age at PE was 16 years (25th-75th percentile, 14-17 years); 61% had underlying conditions. PE did not resolve in 29%, recurrence happened in 9%, and death in 5%. One-third of patients had at least 1 documented abnormal functional finding at follow-up (ventilatory impairments, 31%; impaired aerobic capacity, 31%; dyspnea, 26%; and abnormal diffusing capacity of the lungs to carbon monoxide, 22%). Most abnormalities were transient. When alternative explanations for the impairments were considered, the frequency of post-PE syndrome was lower, ranging between 0.7% and 8.5%. Patients with underlying conditions had significantly higher recurrence, more pulmonary function and ventilatory impairments, and poorer exercise capacity. Exercise intolerance was, in turn, most frequently because of deconditioning than to respiratory or cardiac limitation, highlighting the importance of physical activity promotion in children with PE.

Socioeconomic Factors Influencing Pediatric Peak Oxygen Consumption Prediction

OBJECTIVE

To determine if socioeconomic status (SES) has a greater effect than standard demographic values on predicted peak oxygen consumption (pVO2).

STUDY DESIGN

We conducted a single-institution, retrospective analysis of maximal cardiopulmonary exercise test (CPET) data from 2010 to 2020 for healthy patients age <19 years with body mass index (BMI) percentile (BMI%) between 5-95. Data were sorted by self-identified race, BMI%, and adjusted gross income (AGI); AGI served as a surrogate for SES. Mean percent predicted pVO2 (pppVO2) was compared between groups. Linear regression was used to adjust for differences.

RESULTS

A total of 541 CPETs met inclusion criteria. Mean pppVO2 was 97% ± 22.6 predicted (P < .01) with 30% below criterion standard for normal (85% predicted). After excluding unknown AGI and race, 418 CPETs remained. Mean pppVO2 was lower for Blacks (n = 36) and Latinx (n = 26) compared with Whites (n = 333, P < .01). Mean pppVO2 declined as AGI decreased (P < .01). The differences in pppVO2 between racial categories remained significant when adjusted for BMI% (Black r = -7.3, P = .035; Latinx r = -15.4, P < .01). These differences both decreased in magnitude and were no longer significant when adjusted for AGI (Black r = -6.0, P = .150; Latinx r = -9.3, P = .06).

CONCLUSIONS

Lower SES correlates with lower measured cardiovascular fitness and may confound data interpretation. When using normative reference ranges in clinical decision making, providers should recognize that social determinants of health may influence predicted fitness. Social inequities should be considered when assessing pediatric cardiovascular fitness.

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.

Guidance and standard operating procedures for functional exercise testing in cystic fibrosis

Regular exercise testing is recommended for all people with cystic fibrosis (PwCF). A range of validated tests, which integrate both strength and aerobic function, are available and increasingly being used. Together, these tests offer the ability for comprehensive exercise evaluation. Extensive research and expert consensus over recent years has enabled the adaptation and standardisation of a range of exercise tests to aid the understanding of the pathophysiology related to exercise limitation in PwCF and has led to the development of novel exercise tests which may be applied to PwCF. This article provides expert, opinion-based clinical practice guidance, along with test instructions, for a selection of commonly used valid tests which have documented clinimetric properties for PwCF. Importantly, this document also highlights previously used tests that are no longer suggested for PwCF and areas where research is mandated. This collaboration, on behalf of the European Cystic Fibrosis Society Exercise Working Group, represents expert consensus by a multidisciplinary panel of physiotherapists, exercise scientists and clinicians and aims to improve global standardisation of functional exercise testing of PwCF. In short, the standardised use of a small selection of tests performed to a high standard is advocated.

When two Z-scores meet-analysis of exercise capacity of children and adolescents with Kawasaki disease by a new Z-score model of coronary artery and a new Z-score evaluating peak oxygen consumption : Coronary artery Z-score and peakVO2 Z-score in KD

BACKGROUND

Coronary artery (CA) Z-score system is widely used to define CA aneurysm (CAA). Children and adolescents after acute stage of Kawasaki disease (KD-CA) have a higher risk of developing CAAs if their CA Z-score ≥ 2.5. Z-score system of peak oxygen consumption (Peak VO2 Z-score) allows comparisons across ages and sex, regardless of body size and puberty. We aimed to compare the exercise capacity (EC) indicated by peak VO2 Z-score during cardiopulmonary exercise testing (CPET) directly between KD-CA with different CA Z-score.

METHODS

KD-CA after acute stage who received CPET in the last 5 years were retrospectively recruited. CA Z-score was based on Lambda-Mu-Sigma method. Max-Z was the maximum CA Z-score of different CAs. KD children with Max-Z < 2.5 and ≥ 2.5 were defined as KD-1 and KD-2 groups, respectively. Peak VO2 Z-score was calculated using the equation established based on Hong Kong Chinese children and adolescent database.

RESULTS

One hundred two KD-CA were recruited (mean age: 11.71 ± 2.57 years). The mean percent of measured peak VO2 to predicted value (peak PD%) was 90.11 ± 13.33. All basic characteristics and baseline pulmonary function indices were comparable between KD-1 (n = 87) and KD-2 (n = 15). KD-1 had significantly higher peak VO2 Z-score (p = .025), peak PD% (p = .008), peak metabolic equivalent (p = .027), and peak rate pressure product (p = .036) than KD-2.

CONCLUSIONS

KD-CA had slightly reduced EC than healthy peers. KD-CA with Max-Z ≥ 2.5 had significantly lower peak EC than those < 2.5. Max-Z is potentially useful follow-up indicator after acute stage of KD.

Cardiopulmonary Exercise Testing in Children and Young Adolescents after a Multisystem Inflammatory Syndrome: Physical Deconditioning or Residual Pathology?

Multisystem inflammatory syndrome in children (MIS-C) is a serious health condition that imposes a long-term follow-up. The purpose of our pilot study is to evaluate the usefulness of the cardiopulmonary stress test (CPET) in the follow-up after MIS-C. All patients admitted for MIS-C in our hospital in the 12 months preceding the date of observation were considered for inclusion in the study. Pre-existing cardio-respiratory diseases and/or the lack of collaboration were the exclusion criteria. At enrolment, each subject passed a cardiological examination, rest ECG, echocardiogram, 24 h Holter-ECG, blood tests, and a CPET complete of spirometry. A total of 20 patients met the inclusion criteria (11.76 ± 3.29 years, 13 male). In contrast to the normality of all second-level investigations, CPET showed lower-than-expected peakVO₂ and peak-oxygen-pulse values (50% of cases) and higher-than-expected VE/VCO_2-slope values (95% of cases). A statistically significant inverse correlation was observed between P-reactive-protein values at admission and peakVO₂/kg values (p = 0.034), uric acid values at admission, and peakVO₂ (p = 0.011) or peak-oxygen-pulse expressed as a percentage of predicted (p = 0.021), NT-proBNP values at admission and peakVO₂ expressed as a percentage of predicted (p = 0.046). After MIS-C (4-12 months) relevant anomalies can be observed at CPET, which can be a valuable tool in the follow-up after this condition.

Development of a Pediatric Cardiology Cardiopulmonary Exercise Testing Database

Cardiopulmonary exercise testing (CPET) provides clinicians with information vital to the management of pediatric cardiology patients. CPET can also be used to measure cardiorespiratory fitness (CRF) in these patients. CRF is a robust marker of overall health in children. However, a complete understanding of CRF in pediatric cardiology patients is limited by lack of large, standardized CPET databases. Our purpose was to develop a standardized CPET database, describe available data at our institution, and discuss challenges and opportunities associated with this project. CPETs performed from 1993 to present in an urban pediatric hospital were collected and compiled into a research database. Historical data included demographic and clinical variables and CPET outcomes, and additional variables were calculated and coded to facilitate analyses in these cohorts. Patient diagnoses were coded to facilitate sub-analyses of specific cohorts. Quality assurance protocols were established to ensure future database contributions and promote inter-institutional collaborations. This database includes 10,319 CPETs (56.1% male), predominantly using the Bruce Protocol. Patients ranging from ages 6 to 18 years comprise 86.8% of available CPETs. Diagnosis classification scheme includes patients with structurally normal hearts (n = 3,454), congenital heart disease (n = 3,614), electrophysiological abnormalities (n = 2,082), heart transplant or cardiomyopathy (n = 833), and other diagnoses (n = 336). Historically, clinicians were provided with suboptimal interpretive resources for CPET, often generalizing inferences from these resources to non-representative clinical populations. This database supports representative CRF comparisons and establishes a framework for future CRF-based registries in pediatric patients referred for CPET, ultimately improving clinical decision-making regarding fitness in these populations.

Pediatric Cardiopulmonary Exercise Testing: Interoperability Through Domain Analysis Modeling and a National Survey

PURPOSE

The electronic health record, data science advances, and dynamic environmental and infectious threats to child health highlight the need for harmonized and interoperable approaches to pediatric cardiopulmonary exercise testing (CPET). Accordingly, we developed a terminology harmonization in exercise medicine and exercise science domain analysis model (THEMES DAM) to structure CPET data elements.

METHODS

THEMES DAM identified 114 data elements, including participant information, calibration, equipment, protocols, laboratory personnel, encouragement strategies, and analysis procedures. We used the THEMES DAM, vetted by the international data standards organization HL7, to construct a current-state survey of pediatric CPET centers in the United States. Forty-eight of 101 centers responded to a questionnaire covering seven major topic areas (38 items).

RESULTS

Centers predominantly performed between 100 and 500 tests annually. Cardiac disease represented 55% of referrals. Almost all centers calibrated gas concentrations and flow daily, but 42% never calibrated their treadmill or cycle ergometers. All centers measured V̇O2peakbut calculated differently. Centers used a variety of protocols (e.g., for treadmill: 61%, Bruce; 43%, modified Bruce; 59%, other); 44% calculated CPET slopes from submaximal portions of CPET (e.g., V̇O2-HR). All centers verbally encouraged participants, but only 40% used a standardized approach. The interpretation of CPET was done by physicians (60%), exercise physiologists (25%), exercise technicians (10%), nurses (1%), or others (4%). Ninety-one percent would agree to collaborate in multicenter research, 89% to establish dynamic reference values, and 83% to better interpret CPET.

CONCLUSIONS

The survey data and the implementation of THEMES DAM could accelerate interoperability across multiple centers. This would facilitate a nimble approach to create pediatric reference values responsive to the constantly changing health environment and stimulate novel approaches to CPET research and clinical application.

Association between Cardiopulmonary Capacity and Body Mass Composition in Children and Adolescents with High Body Weight: A Cross-Sectional Study

(1) Background: Excessive body weight is a global problem in the 21st century. Children and adolescents, in particular, are at risk. Recently, there has been an increasing interest in the relationship between aerobic capacity and body composition. Therefore, this study aimed to determine the association between the individual parameters of cardiopulmonary capacity obtained in cardiopulmonary exercise testing (CPET) and selected parameters of body mass composition in high-BMI children and children over the 85th percentile according to the WHO growth reference. (2) Materials and Method: The research included 100 children of school-age (7–15 years) with an excessive BMI, i.e., over the 85th percentile as per the WHO Growth Reference (BMI percentile 95.21 ± 4.65; Z-score BMI: 2.07 ± 0.94). The study consisted of three parts: anthropometric measurements, measurement of body mass composition using a body composition analyzer (TANITA MC-780 S MA) using the bioimpedance method, and a cardiopulmonary exercise test on a pediatric cycle ergometer (Corival Pediatric, Lode BV) using the Godfrey protocol; (3) Results: The correlation between BMI and fat mass (FM) was very high (rho = 0.83; p = 0.00) with moderate body fat percentage (BF%) (rho = 0.48; p = 0.00). There was a relevant correlation between the amount of fat-free mass in total body mass and cardiopulmonary capacity expressed as the absolute aerobic capacity (VO_2peak) (rho = 0.55; p = 0.00). (4) Conclusions: In the case of children and youth with higher BMI, there was a correlation between the amount of fat-free mass in total body mass and cardiopulmonary capacity in terms of absolute aerobic capacity.

Differential Influence of Physical Activity on Cardiopulmonary Performance and Stroke Volume Assessed at Cardiopulmonary Exercise Test in Pectus Excavatum: A Pilot Study

Background

Exercise training increases muscle VO₂ by increasing O₂ transport and O₂ uptake while cardiac output increase might be limited by the conformation of the chest in subjects with pectus excavatum (PE).

Aims

The aim of the present study was to investigate the influence of physical activity (PA) on functional parameters of cardiopulmonary performance and stroke volume obtained at Cardiopulmonary Exercise Test (CPET) in PE.

Methods and Procedures

A cohort of adolescents (15 with PE and 15 age- and sex-matched healthy controls, HC) underwent Cardiopulmonary Exercise Test (CPET) and administration of the International Physical Activity Questionnaire – Short Form (IPAQ-SF) with estimation of weekly PA (METs h^–1⋅week^–1). Determinants of CPET parameters were investigated with multivariable linear regression analysis.

Results

As expected, when compared to HC, PE had lower VO₂ max (37.2 ± 6.6 vs. 45.4 ± 6.4 mL⋅kg^–1⋅min^–1, p < 0.05), and VO₂/HR max (O₂ pulse, 12.1 ± 2.4 vs. 16.2 ± 3.6 mL⋅min^–1⋅bpm^–1, p < 0.05). Importantly, physical activity level was a predictor of VO₂ max (adjusted for sex, body mass index, FEV₁%, and presence of PE, β = 0.085; 95% Cl 0.010 to 0.160, p = 0.029) whereas O₂ pulse was independent from PA level (β = 0.035; 95% Cl −0.004 to 0.074).

Conclusion

Physical activity is a determinant of VO₂ max (cardiopulmonary performance), whereas it appears not to affect O₂ pulse (a measure of stroke volume at peak exercise) related to constrained diastolic filling in PE.

New kids on the CPET: age-appropriate outdoor cardiopulmonary exercise testing in preschoolers

Purpose

Cardiopulmonary exercise testing (CPET) in preschoolers (4–6 years) represents a challenge. Most studies investigating CPET have been limited to older children (> 8 year). However, knowledge of the performance of small children is essential for evaluating their cardiorespiratory fitness. This study strives to compare a modified Bruce protocol with a new age-appropriate incremental CPET during natural movement running outdoors, using a mobile device.

Methods

A group of 22 4–6-year-old healthy children was tested indoor on a treadmill (TM) using the modified Bruce protocol. The results were compared with a self-paced incremental running test, using a mobile CPET device in an outdoor park. The speeds were described as (1) slow walking, (2) slow running, (3) regular running, and (4) running with full speed as long as possible.

Results

Mean exercise time outdoors (6,57 min) was significantly shorter than on the treadmill (11,20 min), \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{O}_{2peak}$$\end{document}V˙O2peak (51.1 ml/min/kg vs. 40.1 ml/min/kg), RER (1.1 vs. 0.98) and important CPET parameters such as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}E$$\end{document}V˙E_max, O₂pulse, heart rate and breath rate were significantly higher outdoors. The submaximal parameter OUES was comparable between both the tests.

Conclusions

Testing very young children with a mobile device is a new alternative to treadmill testing. With a significantly shorter test duration, significantly higher values for almost all cardiopulmonary variables can be achieved without losing the ability to determine VT1 and VT2. It avoids common treadmill problems and allows for individualized exercise testing. The aim is to standardize exercise times with individual protocols instead of standardizing protocols with individual exercise times, allowing for better comparability.

Is the six-minute walk test still reliable compared to cardiopulmonary exercise test for exercise capacity in children with congenital heart disease?

OBJECTIVES

We aimed to assess the validity of the six-minute walk test (6MWT) to reflect the functional capacity of children with congenital heart disease (CHD), evaluate a possible correlation between the 6MWT distance with cardiopulmonary exercise test (CPET) variables, as well as to find a cutoff value to stratification the physical fitness in this population.

METHODS

We enrolled 459 children with CHD, 6-18 years old, who performed a complete CPET and 6MWT on the same day in a cross-sectional observational study. Correlations between variables of CPET and six-minute walking distance (6MWD) were analyzed and cutoff values of 6MWD were identified for the classification of the physical fitness in the population.

RESULTS

The mean distance ambulated during the 6MWT was 578 ± 65 m, 590 ± 65 m for boys, and 562 ± 62 m for girls (p < 0.001). Both VO_2max and %predicted VO_2max showed a correlation with the 6MWT distance (r = 0.35, p < 0.001 and r = 0.51, p < 0.001, respectively), and an inverse correlation was found between VE/VCO2 slope and the 6MWT distance (r = -0.31; p < 0.001). There appeared to be a linear association between 6MWD and VO_2max up to a 6MWD of approximately 600 m. We divided the population into 4 subgroups (boys <130 cm; boys ≥130 cm; girls <130 cm; girls ≥130 cm), and get the cutoff values (554 m, 617 m, 549 m, 587 m) respectively equivalent to 80% of predicted VO_2max. The 6MWT distances of another 102 patients were applied for external verification of the cutoff values.

CONCLUSIONS

Our study provided evidence on when a 6MWT should be considered as a convincing complementary test in the pediatric population with CHD and explored the classification of exercise tolerance using a 6MWD value. The cut-off values for 6MWD may be qualified as an intervention target for exercise rehabilitation.

Cardiovascular Health of Youth During Gender-Affirming Testosterone Treatment: A Review

PURPOSE

Many birth-assigned female/transgender male and nonbinary people (identified as masculine spectrum here) begin gender-affirming testosterone therapy by the age of 24 years. Few data inform assessment of cardiovascular health of masculine spectrum youth as a specific subgroup of the 1.5 million transgender people in the United States. The purpose of this review is to help youth-serving practitioners consider, understand, and evaluate cardiovascular health in adolescent and young adult masculine spectrum patients receiving gender-affirming testosterone treatment.

METHODS

This is a narrative review intended to synthesize a broad body of clinical and research literature.

RESULTS

Common cardiovascular health changes associated with testosterone include increased red blood cell mass and likely insignificant changes in high-density lipoprotein and low-density lipoprotein levels. Changes in heart mass, heart electrophysiology, and endothelial reactivity are likely, based on extrapolation of data from adults. Testosterone may have indirect effects on cardiovascular health through influences on depression, anxiety, stress, and anorexia nervosa as well as on behaviors such as tobacco use.

CONCLUSIONS

Testosterone contributes importantly to the cardiovascular health and well-being of masculine spectrum gender-diverse youth. We need to do a better job of supporting these young people with data on cardiovascular health over the life span.

ARTP statement on cardiopulmonary exercise testing 2021

Cardiopulmonary exercise testing (CPET) has become an invaluable tool in healthcare, improving the diagnosis of disease and the quality, efficacy, assessment and safety of treatment across a range of pathologies. CPET's superior ability to measure the global exercise response of the respiratory, cardiovascular and skeletal muscle systems simultaneously in a time and cost-efficient manner has led to the application of CPET in a range of settings from diagnosis of disease to preoperative assessment. The Association for Respiratory Technology and Physiology Statement on Cardiopulmonary Exercise Testing 2021 provides the practitioner and scientist with an outstanding resource to support and enhance practice, from equipment to testing to leadership, helping them deliver a quality assured service for the benefit of all patient groups.

Correlation of anthropometric index and cardiopulmonary exercise testing in children with pectus excavatum

BACKGROUND

Cardiopulmonary exercise testing (CPET) is a method used to evaluate functional impairment of patients with various diseases.

OBJECTIVE

The objective was to use CPET to estimate the usability of anthropometric index (AI) in patients with pectus excavatum (PE) as a marker of functional impairment caused by chest deformity.

METHODS

The study included 32 paediatric patients (28 males) with PE. Patients underwent CPET using a breath-by-breath exhaled gas analysis method and continuous monitoring of cardiac parameters.

RESULTS

In both groups, two (overall four) patients met criteria for cardiogenic limitation (low VO₂ and low O₂Pulse). Mean VO₂/WR was below two standard deviations (2SD) in patients with less severe PE; other observed parameters were within normal limits (Z-score ± 2 SD). The AI had no observed correlation with peak ventilation, VO₂peak and peak workload.

CONCLUSION

The obtained CPET data do not correlate well with the severity of chest deformity expressed with AI. There were similar physical activity limitations in both examined groups of patients and they did not depend on the severity of the deformity.

Normative cardiopulmonary exercise data for endurance athletes: the Cardiopulmonary Health and Endurance Exercise Registry (CHEER)

AIMS

Accurate interpretation of cardiopulmonary exercise testing (CPET) relies on age, gender, and exercise modality-specific reference values. To date, clinically applicable CPET reference values derived from a source population of endurance athletes (EAs) have been lacking. The purpose of this study was to generate CPET reference values for use in the clinical assessment of EA.

METHODS AND RESULTS

Prospective data accrued during the clinical care of healthy EA were used to derive CPET reference values and to develop novel equations for V˙O2peak. The performance of these equations was compared to the contemporary standard of care equations and assessed in a discrete EA validation cohort. A total of 272 EA (age = 42 ± 15 years, female = 31%, V˙O2peak = 3.6 ± 0.83 L/min) met inclusion criteria and comprised the derivation cohort. V˙O2peak prediction equations derived from general population cohorts described a modest amount of V˙O2peak variability [R2 = 0.58-0.70, root mean square error (RMSE) = 0.46-0.54 L/min] but were mis-calibrated (calibration-in-the-large = 0.45-1.18 L/min) among EA leading to significant V˙O2peak underestimation. Newly derived, externally validated V˙O2peak prediction equations for EA that included age, sex, and height for both treadmill (R2 = 0.74, RMSE = 0.42 L/min) and cycle ergometer CPET (Cycle: R2 = 0.69, RMSE = 0.42 L/min) demonstrated improved accuracy.

CONCLUSION

Commonly used V˙O2peak prediction equations derived from general population cohorts perform poorly among competitive EA. Newly derived CPET reference values including novel V˙O2peak prediction equations may improve the clinical utility of CPET in this rapidly growing patient population.

Alternative to body surface area as a solution to correct systematic bias in pediatric echocardiography Z scores

BACKGROUND

Z scores are the method of choice to report dimensions in pediatric echocardiography. Z scores based on body surface area (BSA) have been shown to cause systematic biases in overweight and obese children. Using aortic valve (AoV) diameters as a paradigm, the aims of this study were to assess the magnitude of Z score underestimation in children with increased body mass index Z score (BMI-Z) and to determine if a predicting model with height and weight as independent predictors would minimize this bias.

METHODS

In this multicenter, retrospective, cross-sectional study, 15,006 normal echocardiograms in healthy children 1-18 years old were analyzed. Residual associations with body size were assessed for previously published Z score. BSA-based and alternative prediction models based on height and weight were developed and validated in separate training and validation samples.

RESULTS

Existing BSA-based Z scores incompletely adjusted for weight, BSA and BMI-Z and led to an underestimation of >0.8 Z score units in subjects with higher BMI-Z, compared to lean subjects. BSA-based models led to overestimation of predicted AoV diameters with increasing weight or BMI-Z. Models using height and weight as independent predictors improved adjustment with body size, including in children with higher BMI-Z.

CONCLUSIONS

BSA-based models result in underestimation of Z scores in patients with high BMI-Z. Prediction models using height and weight as independent predictors minimize residual associations with body size and generate well-fitted predicted values that could apply to all children, including those with low or high BMI-Z.

Cardiopulmonary Capacity in Overweight and Obese Children and Adolescents: A Cross-Sectional Study

Background: One of the objective methods of assessing the level of cardiopulmonary capacity in overweight and obese children and adolescents is cardiopulmonary exercise testing (CPET).

Aims: The purpose of present study is an evaluation of aerobic capacity in high body mass index (BMI) children and adolescents by comparing them with a normal weight control group by CPET.

Methods and Procedures: The subjects were recruited from participants of the Program of Treatment for Overweight and Obese Children organized by a local pediatric rehabilitation center in Poland. Based on BMI for age and gender, two validation groups were selected: (1) a group of overweight children (n = 49) and (2) a group of obese children (n = 48). The study included also 53 normal weight participants as a reference group (REF). The study consisted of two parts: anthropometric measurements and CPET. The Godfrey protocol for CPET was applied.

Outcomes and Results: In this study, obese children and adolescents showed similar absolute VO_2peak values in liters per minute (1.64 L/min) compared to overweight children (1.48 L/min), but significantly higher than children with normal body weight (1.39 L/min). The obese children and adolescents presented lower VO_2peak in relation to body weight (25.44 ml/kg/min) compared to their peers with normal body weight (36.5 ml/kg/min), and overweight children (29.18 ml/kg/min).

Conclusion and Implications: The main finding of our study was recognition of significant differences between cardiopulmonary capacity parameters in obese children in comparison not only to normal weight peers, but to overweight, too.

Improved Carotid Elasticity but Altered Central Hemodynamics and Carotid Structure in Young Athletes

Young athletes most often exceed the physical activity recommendations of the World Health Organization. Therefore, they are of special interest for investigating cardiovascular adaptions to exercise. This study aimed to examine the arterial structure and function of young athletes 12-17 years old and compare these parameters to reference values of healthy cohorts. Carotid intima-media thickness (cIMT), carotid diameter, cIMT÷carotid diameter-ratio (cIDR), arterial compliance (AC), elastic modulus (Ep), β stiffness index (β), and carotid pulse wave velocity (PWVβ) were determined using ultrasound in 331 young athletes (77 girls; mean age, 14.6 ± 1.30 years). Central systolic blood pressure (cSBP) and aortic PWV (aPWV) were measured using the oscillometric device Mobil-O-Graph. Standard deviation scores (SDS) of all parameters were calculated according to German reference values. The 75th and 90th percentiles were defined as the threshold for elevated cIMT and arterial stiffness, respectively. Activity behavior was assessed with the MoMo physical activity questionnaire, and maximum power output with a standard cardiopulmonary exercise test. One-sample t-tests were performed to investigate the significant deviations in SDS values compared to the value "0". All subjects participated in competitive sports for at least 6 h per week (565.6 ± 206.0 min/week). Of the 331 young athletes, 135 (40.2%) had cIMT >75th percentile, 71 (21.5%) had cSBP >90th percentile, and 94 (28.4%) had aPWV>90th percentile. We observed higher cIMT SDS (p < 0.001), cIDR SDS (p = 0.009), and AC SDS (p < 0.001) but lower β SDS (p < 0.001), Ep SDS (p < 0.001), and PWVβ SDS (p < 0.001) compared to the reference cohort. The cSBP SDS (p < 0.001) and aPWV SDS (p < 0.001) were elevated. In conclusion, cIMT and cIDR were higher in young athletes than in a reference cohort. Furthermore, young athletes presented better carotid elasticity and lower arterial stiffness of the carotid artery. However, central arterial stiffness was higher compared to the reference cohort. The thickening of the carotid intima-media complex in combination with a reduction in arterial stiffness indicates a physiological adaptation to exercise in youth.

Insights from Cardiopulmonary Exercise Testing in Pediatric Patients with Hypertrophic Cardiomyopathy

The usefulness of cardiopulmonary exercise test (CPET) in adult hypertrophic cardiomyopathy (HCM) patients is well-known, whereas its role in pediatric HCM patients has not yet been explored. The present study investigates possible insights from a CPET assessment in a cohort of pediatric HCM outpatients in terms of functional and prognostic assessment. Sixty consecutive pediatric HCM outpatients aged <18 years old were enrolled, each of them undergoing a full clinical assessment including a CPET; a group of 60 healthy subjects served as controls. A unique composite end-point of heart failure (HF) related and sudden cardiac death (SCD) or SCD-equivalent events was also explored. During a median follow-up of 53 months (25th–75th: 13–84 months), a total of 13 HF- and 7 SCD-related first events were collected. Compared to controls, HCM patients showed an impaired functional capacity with most of them showing peak oxygen uptake (pVO₂) values of <80% of the predicted, clearly discrepant with functional New York Heart Association class assessment. The composite end-point occurred more frequently in patients with the worst CPETs’ profiles. At the univariate analysis, pVO₂% was the variable with the strongest association with adverse events at follow-up (C-index = 0.72, p = 0.025) and a cut-off value equal to 60% was the most accurate in identifying those patients at the highest risk. In a pediatric HCM subset, the CPET assessment allows a true functional capacity estimation and it might be helpful in identifying early those patients at high risk of events.

Normative Values for Cardiopulmonary Exercise Stress Testing Using Ramp Cycle Ergometry in Children and Adolescents

OBJECTIVES

To provide sex, age, and race specific reference values for ramp cycle ergometer cardiopulmonary exercise test (CPET) in children in the US.

STUDY DESIGN

Retrospective review was conducted of all cardiopulmonary CPET data from our Exercise Physiology Laboratory on healthy children and adolescents (6-18 years) with body mass index between the 5th and 95th percentiles and structurally normal hearts who performed a ramp cycle ergometry stress test between 1999 and 2015. Twenty-eight exercise variables were included: peak oxygen consumption, oxygen consumption at ventilatory anaerobic threshold, peak work rate, resting and peak heart rate and blood pressure, resting pulmonary function testing, and ventilatory responses to progressive exercise using breath-by-breath gas exchange. Owing to the nonlinear association between CPET results and age, fractional polynomials were used in the mixed-effects regression models to describe the sex- and age-specific normative values with 95% CIs, after adjusting for race and body mass index.

RESULTS

We analyzed data on 1829 children (average age, 13.6 ± 2.6 years; 52% male). After 12 years of age, males generally had higher peak values for aerobic capacity and work rate. There were progressive increases with age for both sexes in resting pulmonary function and ventilatory response to exercise, peak aerobic and work rate, and oxygen pulse. Notably, there was an age-related decrease in ventilatory equivalents of oxygen and carbon dioxide at the ventilatory anaerobic threshold.

CONCLUSIONS

Future research using prospective, inclusive, and statistically planned cohorts with standardized laboratory approaches and confirmed interoperability should be considered as a focus for validating normative pediatric CPET values in the future.

ERS International Congress 2020 Virtual: highlights from the Allied Respiratory Professionals Assembly

This article provides an overview of outstanding sessions that were (co)organised by the Allied Respiratory Professionals Assembly during the European Respiratory Society International Congress 2020, which this year assumed a virtual format. The content of the sessions was mainly targeted at allied respiratory professionals, including respiratory function technologists and scientists, physiotherapists, and nurses. Short take-home messages related to spirometry and exercise testing are provided, highlighting the importance of quality control. The need for quality improvement in sleep interventions is underlined as it may enhance patient outcomes and the working capacity of healthcare services. The promising role of digital health in chronic disease management is discussed, with emphasis on the value of end-user participation in the development of these technologies. Evidence on the effectiveness of airway clearance techniques in chronic respiratory conditions is provided along with the rationale for its use and challenges to be addressed in future research. The importance of assessing, preventing and reversing frailty in respiratory patients is discussed, with a clear focus on exercise-based interventions. Research on the impact of disease-specific fear and anxiety on patient outcomes draws attention to the need for early assessment and intervention. Finally, advances in nursing care related to treatment adherence, self-management and patients' perspectives in asthma and chronic obstructive pulmonary disease are provided, highlighting the need for patient engagement and shared decision making. This highlights article provides readers with valuable insight into the latest scientific data and emerging areas affecting clinical practice of allied respiratory professionals.

The V̇e/V̇co2 slope: a useful tool to evaluate the physiological status of children with congenital heart disease

Cardiopulmonary exercise test (CPET) is becoming a key examination to assess physical capacity and disease severity in pediatric cardiology. The V̇e/V̇co₂ slope has been increasingly used as a surrogate marker for morbidity and mortality in adult heart failure, pulmonary arterial hypertension, and for adult patients with congenital heart disease (CHD). Nevertheless, the use of the V̇e/V̇co₂ slope in children remains limited in the absence of reference values and clearly identified clinical determinants. This study aimed to compare the V̇e/V̇co₂ slope in a pediatric cohort with CHD to that of age- and gender-adjusted healthy controls. We also intended to identify the clinical and CPET variables associated with V̇e/V̇co₂ slope in this population. This cross-sectional study was carried out between November 2010 and September 2015 in two tertiary care pediatric cardiology reference centers. A total of 700 children were enrolled (399 CHD and 301 healthy controls). The mean V̇e/V̇co₂ slope was significantly higher in the CHD subjects than in healthy subjects (31.6 ± 4.8 vs. 29.3 ± 4.8; P < 0.001). The V̇e/V̇co₂ slope was higher in children with significant pulmonary regurgitation, tricuspid regurgitation, right ventricular hypertension, and right ventricle outflow tract (RVOT) obstacle. In the CHD group, V̇e/V̇co₂ slope increase was associated with body mass index, the presence of a RVOT obstacle, the number of cardiac catheter procedures, as well as low age, forced vital capacity, tidal volume, and [Formula: see text]. Increased V̇e/V̇co₂ slope was predominantly in children with single ventricle and/or residual right heart abnormalities, suggesting that maldistribution of pulmonary blood flow during exercise is an important CHD-unique determinant of V̇e/V̇co₂ slope.NEW & NOTEWORTHY Using V̇e/V̇co₂ slope is useful for children with congenital heart disease. V̇e/V̇co₂ slope is sensitive to pulmonary blood flow maldistribution during exercise, this concerns congenital heart disease with pulmonary regurgitation, tricuspid regurgitation, right ventricular hypertension, and right ventricle outflow tract obstacle. V̇e/V̇co₂ slope is a good parameter to follow single ventricles and right heart residual lesions (tetralogy of Fallot; pulmonary atresia; truncus arteriosus…).

Reference values and secular trends for cardiorespiratory fitness in children and adolescents with obesity

AIM

To present specific reference values for cardiorespiratory fitness (CRF) in children with obesity and to analyse secular trends of CRF in the studied population.

METHODS

Cardiorespiratory fitness, the maximal oxygen uptake (VO₂ max), was estimated with the Åstrand-Rhyming submaximal bicycle test, in 705 Swedish children (356 girls, 8-20 years) with obesity according to the International Obesity Task Force (IOTF). Data were collected from 1999 to 2013. Secular trends, analysed with multiple linear regression, were adjusted for age, height and body mass index standard deviation score (BMI SDS).

RESULTS

All children had low CRF compared with normal weight standards but there was a marked variability of CRF in children with obesity, which was possible to quantify with the developed obesity specific CRF reference values. The mean value of absolute VO₂ max (L/min) increased with age and relative VO₂ max (mL/kg/min) decreased with age in both boys and girls. There was a negative secular trend in both sexes (P < .001).

CONCLUSION

These are the first obesity specific reference values of CRF in children enabling clinical evaluation in childhood obesity treatment. Cardiorespiratory fitness in children with obesity has declined the last decades, indicating that also within this vulnerable group physical activity has gone down.

Novel Z Scores to Correct Biases Due to Ventricular Volume Indexing to Body Surface Area in Adolescents and Young Adults

BACKGROUND

Reference values for cardiac magnetic resonance imaging (cMRI) in children and young adults are scarce. This leads to risk stratification of patients with congenital heart diseases being based on volumes indexed to body surface area (BSA). We aimed to produce cMRI Z score equations for ventricular volumes in children and young adults and to test whether indexing to BSA resulted in an incorrect assessment of ventricular dilation according to sex, body composition, and growth.

METHODS

We retrospectively included 372 subjects aged < 26 years with either normal hearts or conditions with no impact on ventricular volumes (reference group), and 205 subjects with repaired tetralogy of Fallot (TOF) aged < 26 years. We generated Z score equations by means of multivariable regression modelling. Right ventricular dilation was assessed with the use of Z scores and compared with indexing to BSA in TOF subjects.

RESULTS

Ventricular volume Z scores were independent from age, sex, and anthropometric measurements, although volumes indexed to BSA showed significant residual association with sex and body size. In TOF subjects, indexing overestimated dilation in growing children and underestimated dilation in female compared with male subjects, and in overweight compared with lean subjects.

CONCLUSIONS

Indexed ventricular volumes measured with cMRI did not completely adjust for body size and resulted in a differential error in the assessment of ventricular dilation according to sex and body size. Our proposed Z score equations solved this problem. Future studies should evaluate if ventricular volumes expressed as Z scores have a better prognostic value than volumes indexed to BSA.

Quantification of Cardiorespiratory Fitness in Children with Obesity

PURPOSE

Without consideration for the effects of fat mass, there could be an underestimation of cardiorespiratory fitness in children with obesity leading to a clinical diagnosis of deconditioning and resulting in unrealistic training goals and limitation of physical activities. The purpose of this study was to identify methods of quantifying cardiorespiratory fitness that were less influenced by fat mass.

METHODS

Fifty-three children, 27 with obesity (10.9 ± 1.0 yr) and 26 without obesity (11.0 ± 1.0 yr), volunteered for this study. Maximal oxygen uptake, an indicator of cardiorespiratory fitness, was referenced to lean body mass, body mass, and predicted body mass at the 50th and 85th body mass index percentiles.

RESULTS

Children with obesity carried 18 kg more fat mass and 7 kg more lean body mass compared with children without obesity. Cardiorespiratory fitness based on lean body mass, body mass, and predicted body mass at the 85th percentile was lower in children with obesity compared with children without obesity (P < 0.001). Differences in cardiorespiratory fitness based on predicted body mass at the 50th percentile between children with and without obesity did not reach statistical significance (P = 0.84). Fat mass influenced cardiorespiratory fitness least when referenced to lean body mass or predicted body mass at the 50th percentile (R < 0.26) in contrast to when it was referenced to body mass or predicted body mass at the 85th percentile (R > 0.37).

CONCLUSION

Quantifying cardiorespiratory fitness based on lean body mass or predicted body mass at the 50th percentile could be useful for estimating fitness levels in children with obesity.

Cardiopulmonary Capacity in Children During Exercise Testing: The Differences Between Treadmill and Upright and Supine Cycle Ergometry

Background/Hypothesis: Cardiopulmonary exercise testing (CPET) is used in the assessment of function and prognosis of cardiopulmonary health in children with cardiac and pulmonary diseases. Techniques, such as cardiac MRi, and PET-scan, can be performed simultaneously with exercise testing. Thus, it is desirable to have a broader knowledge about children’s normal cardiopulmonary function in different body postures and exercise modalities. The aim of this study was to investigate the effect of different body positions on cardiopulmonary function in healthy subjects performing CPETs.

Materials and Methods: Thirty-one healthy children aged 9, 12, and 15 years did four CPETs: one treadmill test with a modified Bruce protocol and three different bicycle tests with different body postures, sitting, tilted 45°, and lying flat (0°). For the bicycle tests, a 20-watt ramp protocol with a pedal frequency of 60 ± 5 rotations per minute was used. Continous ECG and breath-by-breath V.O2 measurements was done throughout the tests. Cardiac structure and function including aortic diameter were evaluated by transthoracic echocardiography prior to the tests. Doppler measurements of the blood velocity in the ascending aorta were measured prior to and during the test. Prior to every test, the participants performed pulmonary function tests with maximum voluntary ventilation test.

Results: There is a significantly (p < 0.05) lower peak V.O2 in all bicycle tests compared with the treadmill test. There is lower corrected peak V.O2 (ml kg^−0.67 min⁻¹), but not relative peak V.O2 (ml kg⁻¹ min⁻¹), in the supine compared with the upright bicycle test. There are no differences in peak stroke volume or cardiac output between the bicycle modalities when calculated from aortic blood flow. Peak heart rate decreases from both treadmill to upright bicycle and from upright bicycle to the supine test (0°).

Conclusion: There are no differences in peak cardiac output between the upright bicycle test and supine bicycle tests. Heart rate and corrected peak V.O2 are lower in the supine test (0°) than the upright bicycle test. In the treadmill test, it is a higher absolute and relative peak V.O2. Despite the latter differences, we are convinced that both upright and supine bicycle tests are apt in the clinical setting when needed.

A Systematic Approach to Interpreting the Cardiopulmonary Exercise Test in Pediatrics

The use of cardiopulmonary exercise testing in pediatrics provides critical insights into potential physiological causes of unexplained exercise-related complaints or symptoms, as well as specific pathophysiological patterns based on physiological responses or abnormalities. Clinical interpretation of the results of a cardiopulmonary exercise test in pediatrics requires specific knowledge with regard to pathophysiological responses and interpretative strategies that can be adapted to address concerns specific to the child's medical condition or disability. In this review, the authors outline the 7-step interpretative approach that they apply in their outpatient clinic for diagnostic, prognostic, and evaluative purposes. This approach allows the pediatric clinician to interpret cardiopulmonary exercise testing results in a systematic order to support their physiological reasoning and clinical decision making.

Measurement and Interpretation of Maximal Aerobic Power in Children

The assessment of maximal aerobic power ( V˙O2max ) in both children and adults is an invaluable tool for the evaluation of exercise performance capacity and general physical fitness in clinical, athletic, public health, and research applications. The complexity of means and considerations, as well as varying specific aims of V˙O2max testing, has prevented the formulation of a universally applicable, standard testing protocol, in general, and for children in particular. Numerous tester-controllable factors, such as exercise modality, metabolic measurement system, testing protocol, or data reduction strategies, can affect both the measurement and interpretation of V˙O2max data. Although the general guiding principles are similar, children differ from adults in several aspects. One notable difference is the frequent absence of a discernible V˙O2 plateau in children. Thus, the proper choice of equipment and procedures may be different for children than for adults. It is therefore the aim of this article to highlight the general and pediatric-specific considerations that may affect V˙O2max measurement and interpretation of results.

Appropriate scaling approach for evaluating peak VO2 development in Southern Chinese 8 to 16 years old

Objective

To investigate scaling approaches for evaluating the development of peak VO₂ and improving the identification of low cardiopulmonary fitness in Southern Chinese children and adolescents.

Methods

Nine hundred and twenty Chinese children and adolescents (8 to 16 years) underwent graded cardiopulmonary exercise test on a treadmill until volitional exhaustion. Peak VO₂ was corrected for the effects of body mass by ratio or allometric scaling. Z score equations for predicting peak VO₂ were developed. Correlations between scaled peak VO₂, z scores, body size and age were tested to examine the effectiveness of the approach.

Results

Eight hundred and fifty-two participants (48% male) were included in the analyses. Absolute peak VO₂ significantly increased with age in both sexes (both P<0.05), while ratio-scaled peak VO₂ increased only in males (P<0.05). Allometrically scaled peak VO₂ increased from 11 years in both sexes, plateauing by 12 years in girls and continuing to rise until 15 years in boys. Allometically scaled peak VO₂ was not correlated with body mass, but remained correlated with height and age in all but the older girls. Peak VO₂ z score was not correlated with body mass, height or age.

Conclusions

Absolute and allometric scaled peak VO₂ values are provided for Hong Kong Chinese children and adolescents by age and sex. Peak VO₂ z scores improve the evaluation of cardiopulmonary fitness, allowing comparisons across ages and sex and will likely provide a better metric for tracking change over time in children and adolescents, regardless of body size and age.