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

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.

Overshoot of the Respiratory Exchange Ratio during Recovery from Maximal Exercise Testing in Young Patients with Congenital Heart Disease

Introduction: The overshoot of the respiratory exchange ratio (RER) after exercise is reduced in patients with heart failure. Aim: The present study aimed to investigate the presence of this phenomenon in young patients with congenital heart disease (CHD), who generally present reduced cardiorespiratory fitness. Methods: In this retrospective study, patients with CHD underwent a maximal cardiopulmonary exercise testing (CPET) assessing the RER recovery parameters: the RER at peak exercise, the maximum RER value reached during recovery, the magnitude of the RER overshoot and the linear slope of the RER increase after the end of the exercise. Results: In total, 117 patients were included in this study. Of these, there were 24 healthy age-matched control subjects and 93 young patients with CHD (transposition of great arteries, Fontan procedure, aortic coarctation and tetralogy of Fallot). All patients presented a RER overshoot during recovery. Patients with CHD showed reduced aerobic capacity and cardiorespiratory efficiency during exercise, as well as a lower RER overshoot when compared to controls. RER magnitude was higher in the controls and patients with aortic coarctation when compared to those with transposition of great arteries, previous Fontan procedure, and tetralogy of Fallot. The RER magnitude was found to be correlated with the most relevant cardiorespiratory fitness and efficiency indices. Conclusions: The present study proposes new recovery indices for functional evaluation in patients with CHD. Thus, the RER recovery overshoots analysis should be part of routine CPET evaluation to further improve prognostic risk stratifications in patients with CHD.

Caring for the Aging Patient With Adult Congenital Heart Disease: A Review of Cardiac and Noncardiac Comorbidities

As the demographics of congenital heart disease (CHD) have shifted, there are now more adults living with CHD than children in North America. This presents unprecedented challenges as patients with CHD acquire noncardiac comorbidities and seek care for a variety of reasons, including noncardiac surgery and emergency department (ED) visits. CHD shifts from a one organ problem to a multisystem disease and requires a team of specialists to maintain high-quality longitudinal care. In this review, we summarize the challenges patients with CHD and their providers face as they age. We review the demographics of CHD and health care utilization. We examine the rates of noncardiac comorbidities and the current quality of care received by adult patients with CHD.

The Compatibility of Children with Obesity to Self-Report Aspects of Physical Activity Domains

Questions about the different aspects of physical activity (PA) are commonly asked in the clinical setting, yet their compatibility for use with children, particularly children with obesity (OB) is uncertain. Our aim was to investigate different PA-related questions when compared to an objective maximal cardiopulmonary exercise test (CPET) or validated questionnaires. For this study, 33 normal-weight (NW) (5 to less than 85% BMI percentile) and 35 OB (≥95% BMI percentile) children responded to three self-report PA questions evaluating PA domains (exercise capacity, limitations, and the maintenance of an active lifestyle); they also completed a maximal CPET and two validated questionnaires: the New York Heart Association (NYHA) questionnaire and the international physical activity questionnaire (IPAQ). The results regarding the NW children were highly compatible with their self-reports about exercise capacity (85%), whereas the compatibility was low (40%) in the OB group (p < 0.001). Both OB and NW groups had moderate compatibility between the self-report and objective findings regarding their exercise limitations and lifestyle with no significant differences between the groups. These findings suggest that it is inadvisable to rely on a single-item question by which to assess PA in OB children, and no definite conclusions regarding PA status should be drawn. NW children are more compatible with self-reporting their overall exercise capacity, with more limited compatibilities observed when self-reporting their limitations or lifestyle.