Measures of exercise capacity in adults with congenital heart disease

The oxygen uptake efficiency slope in adults with CHD: group validity

The maximal oxygen uptake (V02 max) is a well-validated measure of cardiorespiratory function that is calculated during a maximal cardiopulmonary exercise test. V02 max enables physicians to objectively assess cardiopulmonary function to aid in decision-making for patients with CHD. A significant proportion of these patients however are unable to achieve a maximal exercise test, and as such, there is a need for reliable submaximal predictors of cardiorespiratory reserve.The oxygen uptake efficiency slope represents a measure of how effectively oxygen is extracted from the lungs and taken into the body and can be calculated from a submaximal exercise test. Its reliability as a predictor of cardiorespiratory reserve has been validated in various patient populations, but there is limited evidence for its validity in adult patients with CHD.Retrospective analysis of cardiopulmonary exercise test data in 238 consecutive patients with CHD who completed a maximal cardiopulmonary exercise test at our tertiary cardiology centre demonstrated a strong correlation between peak V02 and the oxygen uptake efficiency slope (0.936). A strong correlation with peak V02 was also demonstrated when oxygen uptake efficiency slope was calculated at ventilatory anaerobic threshold (OUESVAT), 75% (OUES75), and 90% (OUES90) of the test (0.833, 0.905, 0.927 respectively).In adult patients with CHD who are unable to complete a maximal cardiopulmonary exercise test, the oxygen uptake efficiency slope is a reliable indicator of cardiopulmonary fitness which correlates strongly with peak V02 at or beyond the ventilatory anaerobic threshold. Further research is required to validate the findings in patients with less common anatomies and to assess the relationship between the oxygen uptake efficiency slope and mortality.

The Role of Cardiopulmonary Testing to Risk Stratify Tetralogy of Fallot Patients

Neonatal repair has completely changed the clinical history of patients with tetralogy of Fallot (ToF); however, these patients carry a significant risk of severe arrhythmias and sudden cardiac death in the long term. The exact mechanism for late sudden cardiac death is multifactorial and still not well defined, and the risk stratification for primary prophylaxis in these patients remains challenging. Cardiopulmonary exercise testing (CPET) is a well-established and safe method to assess cardiopulmonary function in children and adults with congenital heart disease. Several parameters obtained with CPET have been identified as potential prognostic of major adverse cardiovascular events in congenital heart disease. CPET is routinely used to assess functional capacity also in patients with ToF, and there is some evidence showing its usefulness in predicting the cardiac adverse events in patients with repaired ToF. Current guidelines recognize the importance of CPET in the evaluation and management of patients with ToF, but there is no clear consensus on which the CPET parameter or level of exercise intolerance, as measured by CPET, is truly predictive of an increased risk of arrhythmia and major adverse cardiovascular events in this population. Therefore, the aim of this narrative review is to describe the current evidence on the potential use of CPET in the risk stratification of patients with repaired ToF.

Anatomical/Physiological Correlates of Functional Capacity in Adults With Repaired and Nonsevere Coarctation of the Aorta

Background

There is limited data regarding the interplay of anatomic and physiologic parameters with exercise capacity in adults with native or recurrent nonsevere coarctation of the aorta (CoA).

Objectives

The objective of this study was to use exercise stress echocardiography and cardiac magnetic resonance imaging to identify anatomic and physiologic correlates of exercise capacity in these patients.

Methods

We conducted a single-center retrospective analysis of 54 adults with nonsevere CoA (repaired or unrepaired) followed at our institution between 2015 and 2020. Resting coarctation gradients were obtained using echocardiography. Exercise gradients and functional capacity were assessed using exercise stress echocardiography. Aorta anatomy was obtained using magnetic resonance imaging.

Results

Coarctation-to-diaphragm ratio correlated with minutes of exercise (r = 0.56, P < 0.01) and metabolic equivalents (r = 0.49, P < 0.01). These relationships remained significant after controlling for use of beta-blockers, valvular disease, and type of coarctation repair. Minutes of exercise correlated with mean resting gradients (r = -0.39, P < 0.05). Coarctation-to-diaphragm ratio correlated with peak and mean resting gradients (r = -0.34, P < 0.05; r = -0.48, P < 0.01). Patients with coarctation-to-diaphragm ratio ≤0.7 achieved fewer metabolic equivalents (11.1 ± 1.9 vs 12.8 ± 2.2, P < 0.05) and minutes of exercise (10.3 ± 2.0 vs 12.6 ± 2.7, P < 0.05).

Conclusions

In patients with nonsevere native or recurrent CoA, reduced exercise capacity is correlated with coarctation severity by anatomic size and gradients. Those with a coarctation-to-diaphragm ratio ≤0.7 may represent a subset of patients with nonsevere CoA whose clinical symptoms are only elicited with exercise stress testing. Exercise stress testing and cross-sectional imaging may help identify those who could be considered for earlier coarctation intervention.

Short-term results of serial cardiopulmonary exercise testing in adults with repaired coarctation of the aorta

BACKGROUND

Data on the evolution of exercise capacity in adults with repaired coarctation of the aorta (CoA) are scarce. We aimed to investigate the evolution and change of measures of exercise capacity obtained by cardiopulmonary exercise testing (CPET) in adults with repaired CoA.

METHODS

Patients 16 years of age and older with CoA, who performed at least two maximal CPETs in our institution, were included in the study. The first and last available tests were used for comparative statistical analysis of common exercise variables.

RESULTS

Sixty patients (43 men) performed serial maximal CPET. Mean age at first assessment was 30 ± 10 years (range 17-68). Mean time between first and last assessment was 3.5 years (range 1-7). Mean peak VO2 was 85.6 ± 20.4% of the predicted value at the initial test, and 87.0 ± 20.5% at the final test (p = 0.294). There were no significant differences in the mean values of oxygen pulse, VO2 at anaerobic threshold, systolic and diastolic blood pressures and peak heart rate between the two assessments. There was a slightly higher VE/VCO2 slope at the final test (p = 0.047). Higher age and Borg scale were found to be related with a decline in percent-predicted peak VO2 from initial to final assessment.

CONCLUSION

In adults with repaired CoA, we found no significant change in peak VO2 during a mean follow-up of 3.5 years, yet a small increase in VE/VCO2 slope was observed. Higher age was predictive for a decline in percent-predicted peak VO2, starting in the third decade of life.

The cardiorespiratory optimal point as a discriminator of lesion severity in adults with congenital heart disease

BACKGROUND

Peak oxygen consumption (VO2peak), which depends on maximal exertion and is reduced in adults with congenital heart disease (ACHD), is associated with lesion severity. The lowest ventilatory equivalent for oxygen (the minimum value of VE/VO2) reflects the cardiorespiratory optimal point (COP) as best possible respiration-circulatory interaction and may discriminate between lesion types without the need for maximal exertion. However, data on COP in ACHD is scarce.

METHODS

We retrospectively analyzed stable ACHD with moderate (N.=13) and severe lesions (N.=17) reporting to our outpatient clinic undergoing cardiopulmonary exercise testing. The primary outcome of the study was the difference of COP between moderate and severe lesions. Secondary outcomes were between group differences of the submaximal variable exercise oxygen uptake efficiency slope (OUES) and peak O2 pulse (O2pulsemax) as a surrogate for peripheral oxygen extraction and stroke volume increase during exercise.

RESULTS

The group of severe lesions displayed higher COP (29.5±7.0 vs. 25.2±6.2, P=0.028) as well as lower O2pulsemax (13.3±8.4 vs. 14.9±3.4 mL/beat/kg 102, P=0.038). VO2peak (17.4±6.5 vs. 20.8±8.5 mL/kg/min, P=0.286) and OUES (1.5±0.7 vs. 1.8±0.9, P=0.613) showed a trend towards lower values in severe lesions. COP was a better between group discriminator than O2pulsemax (area under the curve 73.8% vs. 72.4%).

CONCLUSIONS

As a submaximal variable, COP discriminated between moderate and severe lesions and may prove beneficial in a highly vulnerable population that is often unable to undergo exertional testing.

Impaired Exercise Capacity and Mortality Risk in Adults With Congenital Heart Disease

Background

An association between impaired exercise capacity and risk of mortality has been reported among adults with congenital heart disease (CHD). Over the years, treatment methods have improved and may influence outcome. Hence, we report data from a national cohort reflecting a contemporary population.

Objectives

The purpose of this study was to investigate the association between exercise capacity (workload) and mortality in a large registry-based cohort.

Methods

Data on exercise capacity using cycle ergometer were retrieved from the national registry of CHD. The association between predicted exercise capacity (%ECpred) and mortality was analyzed using Cox regression.

Results

In total, 3,721 adults (>18 years, 44.6% women) with CHD were included. The median age was 27.0 years (IQR: 20.8-41.0 years) and mean %ECpred was 77% ± 20%. Over a mean follow-up of 9.4 ± 6.0 years, there were 214 (5.8%) deaths. The Multivariable Cox regression model showed that moderately and severely impaired exercise capacity (50-<70 %ECpred: HR: 2.1, 95% CI: 1.4-3.2, P < 0.001, and <50 %ECpred: HR: 3.5, 95% CI: 2.1-6.0, P < 0.001) and CHD complexity were associated with higher mortality (moderate complexity: HR: 1.9 95% CI: 1.2-3.0, P = 0.003, great complexity: HR: 2.3 95% CI: 1.3-4.2, P = 0.008) when adjusted for New York Heart Association class, physical activity, cardiovascular medication, sex, impaired systemic ventricular function, and age.

Conclusions

Impaired exercise capacity and CHD complexity are independently associated with all-cause mortality in patients with CHD. Exercise capacity is an easily accessible variable that may be a useful tool for risk assessment in adult patients with CHD, but this needs confirmation in prospective studies.

Exercise in patients with repaired tetralogy of Fallot: a systematic review and meta-analysis

OBJECTIVE

Children and adults with repaired tetralogy of Fallot (rTOF) have an impaired exercise capacity, a less active lifestyle and an increased long-term risk of adverse outcomes compared with healthy peers. This study aimed to summarise the current evidence for the effectiveness and safety of exercise training interventions in patients with rTOF.

METHODS

PubMed/MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, Scopus and reference lists of relevant articles were searched for prospective studies published by November 2021. Random-effects meta-analysis and descriptive synthesis were performed to assess the effectiveness and safety of exercise training in patients with rTOF.

RESULTS

Of the 9677 citations identified, 12 articles were included that reported on 10 unique studies and covered 208 patients with rTOF (range of mean/median age: 7.4-43.3 years). All studies implemented 2 to 7 aerobic or respiratory training sessions per week with durations ranging from 6 to 26 weeks. Meta-analysis of the included randomised controlled trials showed that exercise training was associated with a significant improvement in peak VO₂ (pooled mean difference: +3.1 mL/min/kg; 95% CI: 0.76 to 5.36 mL/min/kg, p=0.019). Cardiac imaging studies revealed no subclinical adverse remodelling after the exercise interventions. No serious adverse events including arrhythmias were reported in these studies.

CONCLUSION

Current evidence suggests that exercise training can improve exercise capacity in patients with rTOF with a low risk for adverse events. Exercise prescription may be a safe and effective tool to help improving outcomes in patients with rTOF.

PROSPERO REGISTRATION NUMBER

CRD42021292809.

Coronary Microvascular Dysfunction in Patients with Congenital Heart Disease

Congenital heart diseases represent a wide range of cardiac malformations. Medical and surgical advances have dramatically increased the survival of patients with congenital heart disease, leading to a continuously growing number of children, adolescents, and adults with congenital heart disease. Nevertheless, congenital heart disease patients have a worse prognosis compared to healthy individuals of similar age. There is substantial overlap in the pathophysiology of congenital heart disease and heart failure induced by other etiologies. Among the pathophysiological changes in heart failure, coronary microvascular dysfunction has recently emerged as a crucial modulator of disease initiation and progression. Similarly, coronary microvascular dysfunction could be important in the pathophysiology of congenital heart diseases as well. For this systematic review, studies on maximal vasodilatory capacity in the coronary microvascular bed in patients with congenital heart disease were searched using the PubMed database. To date, coronary microvascular dysfunction in congenital heart disease patients is incompletely understood because studies on this topic are rare and heterogeneous. The prevalence, extent, and pathophysiological relevance of coronary microvascular dysfunction in congenital heart diseases remain to be elucidated. Herein, we discuss what is currently known about coronary microvascular dysfunction in congenital heart disease and future directions.

Circulating Reactive Oxygen Species in Adults with Congenital Heart Disease

Oxidative stress is an important pathophysiological mechanism in the development of numerous cardiovascular disorders, but few studies have examined the levels of oxidative stress in adults with congenital heart disease (CHD). The objective of this study was to investigate oxidative stress levels in adults with CHD and the association with inflammation, exercise capacity and endothelial function. To this end, 36 adults with different types of CHD and 36 age- and gender-matched healthy controls were enrolled. Blood cell counts, hs-CRP, NT-proBNP, fasting glucose, cholesterol levels, iron saturation and folic acid concentrations were determined in venous blood samples. Levels of superoxide anion radical in whole blood were determined using electron paramagnetic resonance spectroscopy in combination with the spin probe CMH. Physical activity was assessed with the IPAQ-SF questionnaire. Vascular function assessment (EndoPAT) and cardiopulmonary exercise testing were performed in the patient group. Superoxide anion radical levels were not statistically significantly different between adults with CHD and the matched controls. Moreover, oxidative stress did not correlate with inflammation, or with endothelial function or cardiorespiratory fitness in CHD; however, a significant negative correlation with iron saturation was observed. Overall, whole blood superoxide anion radical levels in adults with CHD were not elevated, but iron levels seem to play a more important role in oxidative stress mechanisms in CHD than in healthy controls. More research will be needed to improve our understanding of the underlying pathophysiology of CHD.

Safety and efficacy of exercise training in children and adolescents with congenital heart disease: A systematic review and descriptive analysis

BACKGROUND

While exercise training is beneficial in the prevention and management of many chronic diseases, the role of exercise training in children and adolescents with congenital heart disease is less understood. We sought to determine the safety and efficacy of exercise training in children and adolescents with congenital heart disease.

METHODS

We conducted a systematic search of the following databases: PubMed, CINAHL, EMBASE, Web of Science and SportDiscus. We included randomised controlled trials that incorporated an exercise intervention compared with a non-exercising comparator group and examined safety and efficacy in children and adolescents with congenital heart disease. A descriptive analysis of the included trials was then conducted.

RESULTS

A total of 9 articles from 6 trials (642 participants with varying conditions and disease severity) were included. Significant variability of study participants and outcomes were observed across the trials. No adverse events linked to the exercise interventions were stated. The articles reported numerous positive changes to clinically relevant fitness measures. Exercise capacity improved with exercise training in 3 of 4 trials in which it was measured. Cardiorespiratory fitness showed improvements in 3 of 4 trials. Neuromuscular fitness increased in 1 of 2 trials. Physiological and metabolic parameters were improved, and negative changes were not observed to several clinically important measures (e.g. muscular oxygenation, cardiac measures) in 2 of 2 trials. Physical activity increased in 1 of 3 trials. No articles reported on changes in measures of body composition. Outcomes are varied with little consensus on measurements or assessment methods.

CONCLUSIONS

Exercise training appears to be safe and efficacious for improving physical fitness in children and adolescents with congenital heart disease who have been appropriately screened by their medical team. However, the certainty of the evidence for these findings is low to moderate.

Exercise Capacity and Cardiorespiratory Fitness in Children with Congenital Heart Diseases: A Proposal for an Adapted NYHA Classification

OBJECTIVE

To propose and evaluate an adapted NYHA classification for children with congenital heart disease (CHD) as a feasible clinical tool for classifying patients' fitness, cardiorespiratory efficiency and functional limitations during their ordinary daily activities, which are also characterized by vigorous and competitive physical exercise among peers.

METHODS

This cross-sectional investigation analyzed 332 patients (13.1 ± 3.01 y/o) who underwent surgical repair of CHD and performed Cardiopulmonary Exercise Testing (CPET). Patients were divided into NYHA class I, IIA and IIB by specific questioning regarding functional limitation and performance compared to peers and at strenuous intensity. Class IIA was characterized by slight exercise limitation only for strenuous/competitive activities, whereas IIB for already ordinary physical activities. These NYHA classes were compared with maximal CPET on treadmill.

RESULTS

Patients' exercise capacity (exercise time, METs), aerobic capacity (VO2peak) and chronotropic response were found progressively impaired when NYHA class I was compared with IIA and IIB. Indeed, ventilatory-perfusion mismatch (PETCO2, VE/VCO2) significantly worsened from NYHA class I to IIA, while no difference was found between IIA and IIB.

CONCLUSION

This adapted NYHA-CHD classification could allow regular functional evaluations and accurate assessments by clinicians, leading to facilitated clinical management and timely medical interventions.

Heart Failure Risk Predictions and Prognostic Factors in Adults With Congenital Heart Diseases

In recent decades the number of adults with congenital heart diseases (ACHD) has increased significantly. This entails the need for scrupulous evaluation of the current condition of these patients. The ACHD population is one of the most challenging in contemporary medicine, especially as well-known scales such as the NYHA classification have very limited application. At the moment, there is a lack of universal parameters or scales on the basis of which we can easily capture the moment of deterioration of our ACHD patients' condition. Hence it is crucial to identify factors that are widely available, cheap and easy to use. There are studies showing more and more potential prognostic factors that may be of use in clinical practice: thorough assessment with echocardiography and magnetic resonance imaging (e.g., anatomy, ventricular function, longitudinal strain, shunt lesions, valvular defects, pericardial effusion, and pulmonary hypertension), cardiopulmonary exercise testing (e.g., peak oxygen uptake, ventilatory efficiency, chronotropic incompetence, and saturation) and biomarkers (e.g., N-terminal pro-brain type natriuretic peptide, growth-differentiation factor 15, high-sensitivity troponin T, red cell distribution width, galectin-3, angiopoietin-2, asymmetrical dimethylarginine, and high-sensitivity C-reactive protein). Some of them are very promising, but more research is needed to create a specific panel on the basis of which we will be able to assess patients with specific congenital heart diseases.

Reduced Forced Vital Capacity and the Number of Chest Wall Surgeries are Associated with Decreased Exercise Capacity in Children with Congenital Heart Disease

Low forced vital capacity (FVC) is associated with decreased exercise capacity in CHD. Multiple prior cardiac surgeries have been associated with low FVC. We seek to understand the relationship between low FVC, number of cardiac surgeries and cardiopulmonary response leading to decreased exercise capacity. Retrospective chart review of demographics, surgical history and exercise testing including spirometry was performed in patients with CHD. Single ventricle patients were excluded. Low FVC was defined as a Z-score below the lower limit of normal. Exercise parameters were expressed as a percent of predicted. There were 93 patients with 2 ventricle CHD identified over 34 months with cardiopulmonary exercise testing. The FVC Z-score directly correlated with peak V̇O₂% (R² = 0.07, p < 0.05), and the O₂ pulse% (R² = 0.25, p < 0.0001). The VE/VCO₂ was inversely related to the FVC Z-score (R² = 0.11, p < 0.01). Patients with minimum three prior surgeries had decreased peak VO₂% (63.7 vs. 72.8, p < 0.05), decreased peak O₂ pulse% (80.8 vs. 97.9, p < 0.01) and a lower mean FVC Z-score (- 1.9 vs - 0.38, p < 0.01). The FVC Z-score and number of surgeries both predicted peak V̇O₂% in multivariate analysis. Our study demonstrated that low FVC and three or more prior cardiac surgeries were associated with lower exercise capacity and lower stroke volume response. More cardiac surgeries were also associated with low FVC. However, both low FVC and the number of surgeries were independent predictors of exercise capacity.

Effect of oxygen therapy on exercise performance in patients with cyanotic congenital heart disease: Randomized-controlled trial

BACKGROUND

Patients with unrepaired cyanotic congenital heart disease (CHD) suffer from aggravated hypoxemia during exercise. We tested the hypothesis that supplemental oxygen improves exercise performance in these patients.

METHODS

In this randomized, sham-controlled, single-blind, cross-over trial cyanotic CHD-patients underwent four cycle exercise tests to exhaustion, while breathing either oxygen-enriched (FiO₂ 0.50, oxygen) or ambient air (FiO₂ 0.21, air) using incremental (IET) or constant work-rate (CWRET) exercise test protocols (75% of maximal work rate achieved under FiO₂ 0.21). Pulmonary gas-exchange, electrocardiogram, arterial blood gases, oxygen saturation (SpO₂), cerebral and quadriceps muscle tissue oxygenation (CTO and QMTO) by near-infrared spectroscopy were measured.

RESULTS

We included seven patients with cyanotic CHD (4 Eisenmenger syndrome, 3 unrepaired cyanotic defects, 4 women) median (quartiles) age 36 (32;50) years, BMI 23 (20;26) kg/m² and SpO₂ at rest 87 (83;89) %. When comparing supplemental oxygen with air during exercise, maximal work-rate in IET increased from 76 (58;114) Watts to 83 (67;136) Watts, median difference 9 (0;22) W (p = 0.046) and CWRET-time increased from 412 s (325;490) to 468 s (415;553), median increase 56 (39;126) s (p = 0.018). In both IET and CWRET SpO₂ was significantly higher and ventilatory equivalent for carbon dioxide significantly lower at end-exercise with oxygen compared to air, whereas CTO and QMTO did not significantly differ.

CONCLUSIONS

Patients with cyanotic CHD significantly improved their exercise performance, in terms of maximal work-rate and endurance time along with an improved arterial oxygenation and ventilatory efficiency with supplemental oxygen compared to air.

Maximal versus sub-maximal effort during cardiopulmonary exercise testing in adults with congenital heart disease: outcome analysis of short-term cardiac-related events

Peak respiratory exchange ratio is an objective marker of patient effort during cardiopulmonary exercise testing. We evaluated exercise variables in 175 adult congenital heart disease patients and the impact of respiratory exchange ratio on the prognostic value of exercise variables for short-term cardiac-related events. Of 175 patients, 110 completed the exercise test with a peak respiratory exchange ratio of ≥1.10 and the remaining 65 had a peak respiratory exchange ratio of <1.10. Peak oxygen consumption, the percentage of oxygen consumption at the ventilatory threshold, peak heart rate, percentage predicted peak heart rate, double product, oxygen uptake efficiency slope, and the number of patients with exercise oscillatory ventilation were reduced significantly in patients with a respiratory exchange ratio of <1.10 compared to those with a respiratory exchange ratio of ≥1.10. After a median follow-up of 21 months, total cardiac-related events occurred in 37 (21%) patients. Multivariate Cox proportional hazard analysis showed that the percentage predicted peak oxygen consumption, and oxygen uptake efficiency slope were independent predictors of cardiac-related events only in patients with a peak respiratory exchange ratio of ≥1.10. Sub-maximal exercise performance can be preserved in adult congenital heart disease patients. The percentage predicted oxygen consumption and the oxygen uptake efficiency slope are two independent predictors for short-term cardiac-related events in adult congenital heart disease patients.

Diagnosis and treatment of right ventricular dysfunction in congenital heart disease

Right ventricular (RV) function is important for clinical status and outcomes in children and adults with congenital heart disease (CHD). In the normal RV, longitudinal systolic function is the major contributor to global RV systolic function. A variety of factors contribute to RV failure including increased pressure- or volume-loading, electromechanical dyssynchrony, increased myocardial fibrosis, abnormal coronary perfusion, restricted filling capacity and adverse interactions between left ventricle (LV) and RV. We discuss the different imaging techniques both at rest and during exercise to define and detect RV failure. We identify the most important biomarkers for risk stratification in RV dysfunction, including abnormal NYHA class, decreased exercise capacity, low blood pressure, and increased levels of NTproBNP, troponin T, galectin-3 and growth differentiation factor 15. In adults with CHD (ACHD), fragmented QRS is independently associated with heart failure (HF) symptoms and impaired ventricular function. Furthermore, we discuss the different HF therapies in CHD but given the broad clinical spectrum of CHD, it is important to treat RV failure in a disease-specific manner and based on the specific alterations in hemodynamics. Here, we discuss how to detect and treat RV dysfunction in CHD in order to prevent or postpone RV failure.

Impaired pulmonary function and its association with clinical outcomes, exercise capacity and quality of life in children with congenital heart disease

BACKGROUND

Impaired pulmonary function is an independent predictor of mortality in adult congenital heart disease (CHD), but has been scarcely studied in the paediatric CHD population.

AIMS

To compare the pulmonary function of children with CHD to healthy controls, and evaluate its association with clinical outcomes, exercise capacity, and quality of life.

METHODS

Cross-sectional multicentre study among 834 children (555 CHD and 279 control subjects) who underwent a complete spirometry and a cardiopulmonary exercise test (CPET). The 5th centile (Z-score = -1.64) was used to define the lower limit of normal. The association of clinical and CPET variables with spirometry was studied using a multivariate analysis. Children and their parents filled in the Kidscreen health-related quality of life questionnaire.

RESULTS

Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) Z-scores values were lower in children with CHD than controls (-0.4 ± 1.5 vs. 0.4 ± 1.3, P < 0.001 and -0.5 ± 1.4 vs. 0.4 ± 1.2, P < 0.001, respectively), without any obstructive airway disorder. Restrictive pattern was more frequent in CHD patients than in controls (20% vs. 4%, P < 0.0001). FVC Z-scores were predominantly impaired in complex CHD, such as heterotaxy (-1.1 ± 0.6), single ventricle (-1.0 ± 0.2), and complex anomalies of the ventricular outflow tracts (-0.9 ± 0.1). In multivariate analysis, FVC was associated with age, body mass index, peak oxygen uptake, genetic anomalies, the number of cardiac surgery and cardiac catheter procedures. FVC and FEV1 correlated with self and proxy-related quality of life scores.

CONCLUSION

These results suggest that pulmonary function should be monitored early in life, from childhood, in the CHD population.

TRIAL REGISTRATION NUMBER

NCT01202916, post-results.

Exercise physiology in pulmonary hypertension patients with and without congenital heart disease

Background

Cardiopulmonary exercise testing allows the assessment of integrative cardiopulmonary response to exercise.

Aims

The aim of the study was to better understand the exercise physiology in pulmonary arterial hypertension related to adult congenital heart disease compared to non-adult congenital heart disease patients by means of cardiopulmonary exercise testing parameters.

Methods

The present is a multicentre retrospective study which includes pulmonary hypertension group 1 and group 4 patients. All subjects underwent full clinical and instrumental evaluation, including cardiopulmonary exercise testing and right heart catheterization.

Results

One hundred and sixty-seven pulmonary hypertension patients (93 women and 74 men, 57 adult congenital heart disease and 110 non-adult congenital heart disease) were enrolled. Adult congenital heart disease patients had higher pulmonary pressure (mean pulmonary arterial pressure: 59.8 ± 19.5 mmHg vs 44.6 ± 16.5 mmHg, p < 0.001) and lower pulmonary blood flow (pulmonary blood flow: 3.3 (2.1–4.3) l/min vs 4.5 (3.8–5.4) l/min, p < 0.001). At cardiopulmonary exercise testing they had lower peak oxygen uptake/kg (12.8 ± 3.8 ml/kg/min vs 15.5 ± 4.2 ml/kg/min, p < 0.001) and higher ventilation/carbon dioxide elimination slope (53.2 (43.3–64.8) vs 44.0 (34.6–51.6), p < 0.001). When patients were paired for gender and peak oxygen uptake ( ± 1 ml/kg/min), obtaining 44 pairs, adult congenital heart disease patients had higher pulmonary pressure (mean pulmonary arterial pressure: 58.4 ± 20.2 mmHg vs 42.8 ± 16.8 mmHg, p < 0.001) and ventilation/carbon dioxide elimination slope (51.2 (43.4–63.6) vs 44.9 (35.4–55.1), p = 0.033).

Conclusions

In pulmonary arterial hypertension-adult congenital heart disease patients, pulmonary pressure and ventilation/carbon dioxide elimination slope are higher compared to non-adult congenital heart disease pulmonary hypertension patients, while pulmonary blood flow and peak oxygen uptake are lower. After matching patients for gender and peak oxygen uptake, pulmonary pressure and ventilation/carbon dioxide elimination remain higher in adult congenital heart disease patients suggesting that the long-term adaptation to high pulmonary pressure, hypoxia and low pulmonary blood flow, as well as a persisting shunt has, at least partially, preserved exercise performance of pulmonary arterial hypertension-adult congenital heart disease patients.

[Cardiac rehabilitation in adults with congenital heart diseases]

The great advances in the medical and surgical management of congenital heart diseases have allowed many children to reach adulthood with often a good hemodynamic result. Nevertheless most of these adults have a limitation of their functional capacity. This limitation is more or less important, penalizes them in their daily life and alters their quality of life. The origin of this limitation is generally multifactorial. It is linked, of course, to the severity of the heart disease and the quality of the operative result. But there is very often a physical deconditioning. It can be secondary to the heart disease but is often secondary to a lack of physical activity. It is the parents, sometimes overprotective, but frequently the doctors who imposed, often wrongly, this restriction. It is essential to take this dimension into account in view of the important benefits expected for health and quality of life. Cardiac rehabilitation is a privileged tool for providing advice in a suitable environment. This requires close collaboration between cardiac rehabilitators and congenital cardiologists to offer appropriate care. We bring here some reflections and the basic elements to guide the re-training of these patients.

Design and rationale of the Fontan Udenafil Exercise Longitudinal (FUEL) trial

The Fontan operation creates a circulation characterized by elevated central venous pressure and low cardiac output. Over time, these characteristics result in a predictable and persistent decline in exercise performance that is associated with an increase in morbidity and mortality. A medical therapy that targets the abnormalities of the Fontan circulation might, therefore, be associated with improved outcomes. Udenafil, a phosphodiesterase type 5 inhibitor, has undergone phase I/II testing in adolescents who have had the Fontan operation and has been shown to be safe and well tolerated in the short term. However, there are no data regarding the long-term efficacy of udenafil in this population. The Fontan Udenafil Exercise Longitudinal (FUEL) Trial is a randomized, double-blind, placebo-controlled phase III clinical trial being conducted by the Pediatric Heart Network in collaboration with Mezzion Pharma Co, Ltd. This trial is designed to test the hypothesis that treatment with udenafil will lead to an improvement in exercise capacity in adolescents who have undergone the Fontan operation. A safety extension trial, the FUEL Open-Label Extension Trial (FUEL OLE), offers the opportunity for all FUEL subjects to obtain open-label udenafil for an additional 12 months following completion of FUEL, and evaluates the long-term safety and tolerability of this medication. This manuscript describes the rationale and study design for FUEL and FUEL OLE. Together, these trials provide an opportunity to better understand the role of medical management in the care of those who have undergone the Fontan operation.

Risk of Dementia in Adults With Congenital Heart Disease: Population-Based Cohort Study

BACKGROUND

More children with congenital heart disease (CHD) are surviving to adulthood, and CHD is associated with risk factors for dementia. We compared the risk of dementia in CHD adults to that of the general population.

METHODS

In this cohort study, we used medical registries and a medical record review covering all Danish hospitals to identify adults with CHD diagnosed between 1963 and 2012. These individuals with CHD were followed from January 1, 1981, 30 years of age, or date of first CHD registration (index date for matched members of the general population cohort) until hospital diagnosis of dementia, death, emigration, or end of study (December 31, 2012). For each individual with CHD, we identified 10 members of the general population utilizing the Danish Civil Registration System matched on sex and birth year. We computed cumulative incidences and hazard ratios (HRs) of dementia, adjusting for sex and birth year.

RESULTS

The cumulative incidence of dementia was 4% by 80 years of age in 10 632 adults with CHD (46% male). The overall HR comparing adults with CHD with the general population cohort was 1.6 (95% confidence interval [CI], 1.3-2.0). The HR among individuals with CHD without extracardiac defects was 1.4 (95% CI, 1.1-1.8). Adults with mild-to-moderate CHD had an HR of 1.5 (95% CI, 1.1-2.0), whereas the HR was 2.0 (95% CI, 1.2-3.3) for severe CHD, including univentricular hearts. The HR for early onset dementia (<65 years of age) was 2.6 (95% CI, 1.8-3.8), whereas the late-onset HR was 1.3 (95% CI, 1.0-1.8).

CONCLUSIONS

CHD was associated with an increased risk of dementia compared with the general population, in particular for early onset dementia. Further understanding of dementia risk in the population with CHD is a potential target for future investigation.

The Role of Cardiopulmonary Exercise Testing for Decision Making in Patients with Repaired Tetralogy of Fallot

Tetralogy of Fallot is the most common form of cyanotic congenital heart disease. As a result of the surgical strategies employed at the time of initial repair, chronic pulmonary regurgitation (PR) is prevalent in this population. Despite sustained research efforts, patient selection and timing of pulmonary valve replacement (PVR) to address PR in young asymptomatic patients with repaired tetralogy of Fallot (rToF) remain a fundamental but as yet unanswered question in the field of congenital heart disease. The ability of the heart to compensate for the chronic volume overload imposed by PR is critical in the evaluation of the risks and benefits of PVR. The difficulty in clarifying the functional impact of PR on the cardiovascular capacity may be in part responsible for the uncertainty surrounding the timing of PVR. Cardiopulmonary exercise testing (CPET) may be used to assess abnormal cardiovascular response to increased physiologic demands. However, its use as a tool for risk stratification in asymptomatic adolescents and young adults with rToF is still ill-defined. In this paper, we review the role of CPET as a potentially valuable adjunct to current risk stratification strategies with a focus on asymptomatic rToF adolescents and young adults being considered for PVR. The role of maximal and submaximal exercise measurements to identify young patients with a decreased or borderline low peak VO₂ resulting from impaired ventricular function is explored. Current knowledge gaps and research perspectives are highlighted.

An evaluation of the validity of the pre-operative oxygen uptake efficiency slope as an indicator of cardiorespiratory fitness in elderly patients scheduled for major colorectal surgery

This study aimed to investigate the validity of the oxygen uptake efficiency slope as an objective and submaximal indicator of cardiorespiratory fitness in elderly patients scheduled for major colorectal surgery. Patients ≥ 60 years of age, with a metabolic equivalent score using the Veterans Activity Questionnaire ≤ 7 and scheduled for major colorectal surgery participated in a pre-operative cardiopulmonary exercise test. The oxygen uptake efficiency slope was calculated up to different exercise intensities, using 100%, 90% and 80% of the exercise data. Data from 71 patients (47 men, mean (SD) age 75.2 (6.7) years) were analysed. The efficiency slope obtained from all the data was statistically significantly different from the values when 90% (p = 0.027) and 80% (p = 0.023) of the data were used. The 90% and 80% values did not differ significantly from each other (p = 0.152). Correlations between the oxygen uptake efficiency slope and the peak oxygen uptake ranged from 0.816 to 0.825 (all p < 0.001), and correlations between oxygen uptake efficiency slope and the ventilatory anaerobic threshold ranged from 0.793 to 0.805 (all p < 0.001). Receiver operating characteristic curves showed that the oxygen uptake efficiency slope is a sensitive and specific predictor of a peak oxygen uptake ≤ 18.2 ml.kg^-1 .min^-1 , with an area under the curve (95%CI) of 0.876 (0.780-0.972, p < 0.001) and a ventilatory anaerobic threshold ≤ 11.1 ml.kg^-1 .min^-1 , with an area under the curve (95%CI) of 0.828 (0.726-0.929, p < 0.001). These correlations suggest that the oxygen uptake efficiency slope provides a valid (sub)maximal measure of cardiorespiratory fitness in these patients, and the predictive ability described indicates that it might help discriminate patients at higher risk of postoperative morbidity. However, future research should investigate the prognostic value of the oxygen uptake efficiency slope for postoperative outcomes.

[Cardiac rehabilitation for children and adults with congenital heart disease]

Advances in heart surgery over the past 30 years have significantly improved the prognosis of congenital heart diseases (CHD). Therefore, the epidemiology of CHD has changed dramatically with a shift of mortality from pediatrics to adulthood and an increased prevalence of complex CHD. Today, caregivers and patients focus their interests to new perspectives: improving the quality of life, practicing sports, improving psychosocial care. Cardiac rehabilitation is completely integrated in these new therapeutic strategies. The starting point is the cardiopulmonary exercise test (CPET), with the measurement of oxygen uptake, or "VO2". CPET is now recommended in the follow-up of the adults with CHD. Maximum oxygen uptake correlates to the quality of life of children and adults with CHD. The principles of the rehabilitation in patients with heart failure may usually be applied to CHD patients. Some studies in complex CHD showed improvement of VO2 and quality of life after rehabilitation, without any adverse events. However few physicians have the experience in rehabilitation among CHD patients, especially children. Randomized trials on cardiac rehabilitation in adult and pediatric CHD patients are essential to increase the level of evidence and lead to specific guidelines in this population.

Assessing Late Cardiopulmonary Function in Patients with Repaired Tetralogy of Fallot Using Exercise Cardiopulmonary Function Test and Cardiac Magnetic Resonance

BACKGROUND

Patients with repaired tetralogy of Fallot (TOF) usually experience progressive right ventricle (RV) dysfunction due to pulmonary regurgitation (PR). This could further worsen the cardiopulmonary function. This study aimed to compare the changes in patient exercise cardiopulmonary test and cardiac magnetic resonance imaging, and consider the implication of these changes.

METHODS

Our study examined repaired TOF patients who underwent cardiopulmonary exercise test (CPET) to obtain maximal (peak oxygen consumption, peak VO2) and submaximal parameters (oxygen uptake efficiency plateau, oxygen uptake efficiency plateau (OUEP), and ratio of minute ventilation to carbon dioxide production, VE/VCO2 slope). Additionally, the hemodynamic status was assessed by using cardiac magnetic resonance. Criteria for exclusion included TOF patients with pulmonary atresia, atrioventricular septal defect, or absence of pulmonary valve syndrome.

RESULTS

We enrolled 158 patients whose mean age at repair was 7.8 ± 9.1 years (range 0.1-49.2 years) and the mean patient age at CPET was 29.5 ± 12.2 years (range 7.0-57.0 years). Severe PR (PR fraction ≥ 40%) in 53 patients, moderate in 55, and mild (PR fraction < 20%) in 50 patients were noted. The mean RV end-diastolic volume index (RVEDVi) was 113 ± 35 ml/m(2), with 7 patients observed to have a RVEDVi > 163 ml/m(2). The mean left ventricular ejection fraction (LVEF) was 63 ± 8%, left ventricular end-diastolic volume index (LVEDVi) was 65 ± 12 ml/m(2), and LVESVi was 25 ± 14 ml/m(2). CPET revealed significantly decreased peak VO2 (68.5 ± 14.4% of predicted), and fair OUEP (90.3 ± 14.1% of predicted) and VE/VCO2 slope (27.1 ± 5.3). PR fraction and age at repair were negatively correlated with maximal and submaximal exercise indicators (peak VO2 and OUEP). Left ventricular (LV) function and size were positively correlated with peak VO2 and OUEP.

CONCLUSIONS

The results of CPET showed that patients with repaired TOF had a low maximal exercise capacity (peak VO2), but a fair submaximal exercise capacity (OUEP and VE/VCO2 slope), suggesting limited exercise capability in high intensity circumstances. PR, LV function and age at total repair were the most important determinants of CPET performance.

KEY WORDS

Cardiac magnetic resonance; Cardiopulmonary exercise function; Pulmonary regurgitation; Surgical age; Tetralogy of Fallot.

Prognostic value of the post-training oxygen uptake efficiency slope in patients with coronary artery disease

BACKGROUND

Peak oxygen uptake is an independent predictor of mortality in patients with coronary artery disease (CAD). However, patients with CAD are not always capable of reaching peak effort, and therefore submaximal gas exchange variables such as the oxygen uptake efficiency slope (OUES) have been introduced. Baseline exercise capacity as expressed by OUES provides prognostic information and this parameter responds to training. Therefore, we aimed to assess the prognostic value of post-training OUES in patients with CAD.

METHODS

We included 960 patients with CAD (age 60.6 ± 9.5 years; 853 males) who completed a cardiac rehabilitation program between 2000 and 2011. The OUES was calculated before and after cardiac rehabilitation and information on mortality was obtained. The relationships of post-training OUES with all-cause and cardiovascular (CV) mortality was assessed by Cox proportional hazards regression analyses. Receiver operator characteristic curve analysis was performed in order to obtain the optimal cut-off value.

RESULTS

During 7.37 ± 3.20 years of follow-up (range: 0.45-13.75 years), 108 patients died, among whom 47 died due to CV reasons. The post-training OUES was related to all-cause (hazard ratio: 0.50, p < 0.001) and CV (hazard ratio: 0.40, p < 0.001) mortality. When significant covariates, including baseline OUES, were entered into the Cox regression analysis, post-training OUES remained related to all-cause and CV mortality (hazard ratio: 0.40, p < 0.01 and 0.26, p < 0.01, respectively). In addition, the change in OUES due to exercise training was positively related to mortality (hazard ratio: 0.49, p < 0.01).

CONCLUSION

Post-training OUES has stronger prognostic value compared to baseline OUES. The lack of improvement in exercise capacity expressed by OUES after an exercise training program relates to a worse prognosis and can help distinguish patients with favorable and unfavorable prognoses.

Comparison of the Degree of Exercise Tolerance in Children After Surgical Treatment of Complex Cardiac Defects, Assessed Using Ergospirometry and the Level of Brain Natriuretic Peptide

Children who underwent surgery for complex congenital heart defects present worse exercise capacity than their healthy peers. In adults and adolescents, heart failure is assessed on the basis of clinical symptoms using the New York Heart Association (NYHA) score, while in an infant Ross scale; heart failure can also be evaluated by other parameters. The purpose of this study was to compare the degree of exercise tolerance in children after surgery for complex heart defects, assessed by the ratio of maximum oxygen uptake (VO2max) and the brain natriuretic peptide (N-terminal fragment of the prohormone brain-type natriuretic peptide [NT-proBNP]) concentration.The study group consisted of 42 children, ages 9 to 17 years (mean 14.00 ± 2.72). Among them there were 22 children with tetralogy of Fallot (ToF) after total correction, 18 children with transposition of the great arteries (d-TGA) after the arterial switch operation, and 2 children with single ventricle (SV) after the Fontan operation. All but 1 child were in NYHA class I. The control group consisted of 20 healthy children. Outcomes of interest were the ratio of VO2max, determined during ergospirometry, and the level of NT-proBNP. The statistical analysis was performed and the groups were considered significantly different for P < 0.05.There was no statistically significant correlation between NT-proBNP and maximum oxygen uptake (VO2) kg min in the study group compared with the control group.The VO2max in the test group had a mean value less (34.6 ± 8.0) than controls (38.4 ± 7.7), and the differences were statistically significant (P = 0.041). In contrast, the average concentration of NT-proBNP in the study group was higher than controls (117.9 ± 74.3 vs 18.0 ± 24.5), and these differences were statistically significant (P < 0.001).After operations for complex heart defects (ToF, TGA, and SV), children have worse heart function parameters and exercise capacity than the healthy population. To control this, we recommend postoperative ergospirometry and determination of NT-proBNP concentrations.

[Assessment of exercise capacity in congenital heart disease]

For many years, the treatment of congenital heart diseases has been a field in which, based on the seriousness of these conditions, treatment options were viewed with the greatest deference. This has conditioned, in many cases, the interventions to be undertaken in each. In this sense, exercise was thought to have a negative impact and thus the practise of almost any physical activity was limited. Although there has recently been a change in the paradigm with respect to exercise, this idea continues to hold sway. For many cardiopathies, the information obtained through a stress test is essential in order to implement and supervise an exercise program. The aim of this study is to analyze the parameters within the stress test which allow for an adequate stratification of the risk to subjects with congenital heart diseases who undertake exercise, as well as their values in accordance with the type of pathology, the gravity of such, and the age of the patients. Furthermore, these parameters will be analyzed for both their survival markers and the protocols that can best be adjusted for patients with these characteristic.