Oxygen uptake efficiency slope: a reliable surrogate parameter for exercise capacity in healthy and cardiac children?

Abstract

ObjectivesCardiopulmonary exercise test (CPET) provides accurate evaluation of physical capacity and disease severity in children with congenital heart disease (CHD). However, full participation to obtain optimal measure of VO2max may be difficult. As an alternative, the oxygen uptake efficiency slope (OUES) is a reproducible and reliable parameter measured during CPET, which does not require a maximal exercise to be interpretable. This study aimed to evaluate the OUES of a large cohort of children with CHD, in comparison with healthy controls. We also intended to identify, in this specific population, the clinical and CPET variables associated with the OUES.MethodsThis cross-sectional study was carried out between November 2010 and September 2015 in two tertiary care paediatric and congenital cardiology centres.Results709 children were included (407 CHD and 302 healthy controls). The association of clinical characteristics with weight-normalised OUES (OUESkg) was studied using a multivariable analysis. The mean OUESkg was significantly lower in CHD than in healthy controls (38.6±8.5 and 43.9±8.5; p<0.001, respectively), especially in the most severe CHD. The OUESkg correlated with VO2max (r=0.85, p<0.001), with cut-off values for normal exercise capacity of 38.4 in boys and 31.0 in girls. The decrease of OUESkg was associated with increased age, increased Body Mass Index, number of cardiac catheter or surgical procedures, female gender and decreased forced vital capacity (Z-score).ConclusionThe OUES is significantly impaired in children with CHD and strongly correlates with VO2max. The OUES has the same clinical determinants as VO2max and therefore may be of interest in submaximal exercise.Trial registration numberNCT01202916.

Cardiopulmonary Exercise Testing in Repaired Tetralogy of Fallot: Multiparametric Overview and Correlation with Cardiac Magnetic Resonance and Physical Activity Level

“…Very few data are available on the oxygen uptake efficiency slope (OUES) in the rToF population [21,41], although it has already been demonstrated to be an independent and reproducible measure of cardiorespiratory function that does not require maximal exercise [42]. It has also been proposed to be a valuable prognostic factor in patients with chronic heart failure [43,44], candidates for heart transplant [45] and complex congenital heart disease (Fontan) patients [46].…”

Health-related quality of life and physical activity in children with inherited cardiac arrhythmia or inherited cardiomyopathy: the prospective multicentre controlled QUALIMYORYTHM study rationale, design and methods

“…The age-and gender-matched control group will be defined using the same method as in our previous paediatric exercise test studies [4,5,[20][21][22]. Children aged 6 to 17 years old referred to the paediatric cardiology consultation for a non-severe functional symptom linked to exercise (murmur, palpitation, or dyspnoea) or for a medical sports certificate will be assessed for eligibility.…”

“…• The exercise capacity will be assessed by a cardiopulmonary exercise test (CPET), using the same methodology as in our previous paediatric CPET studies [5,20,21,33]. The following variables will be measured: maximum oxygen uptake (VO2 max ); ventilatory anaerobic threshold (VAT); ventilatory efficiency (VE/VCO2 slope), oxygen uptake efficiency slope (OUES), and maximum oxygen pulse (VO2 max / maximum heart rate).…”

Health-Related Quality of Life and Physical Activity in Children with Inherited Cardiac Arrhythmia or Inherited Cardiomyopathies: The Prospective Multicentre Controlled QUALIMYORYTHM Study Rationale, Design and Methods.

“…The age-and gender-matched control group will be de ned using the same method as in our previous paediatric exercise test studies [4,5,[20][21][22]. Children aged 6 to 18 years old referred to the paediatric cardiology consultation for a non-severe functional symptom linked to exercise (murmur, palpitation, or dyspnoea) or for a medical sports certi cate will be assessed for eligibility.…”