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Assessment of Vascular Function in Patients With Chronic Kidney Disease
Published on: June 16, 2014
Early and Stage-Dependent Cardiopulmonary Fitness Impairment in Pediatric CKD
Oscar Werner1,2,3, Marc Fila1,4, Fanchon Herman5
1Department of Specialized Pediatrics, Unit of Pediatric Cardiology and Nephrology, Montpellier University Hospital, France.
Insights
Children with chronic kidney disease (CKD) have significantly lower cardiopulmonary fitness, with impaired maximal oxygen uptake (VO2max) evident even in early stages. This reduced fitness is linked to clinical factors, suggesting early screening is crucial.
Area of Science:
- Pediatric Nephrology
- Cardiovascular Health in Chronic Disease
- Exercise Physiology
Background:
- Children with chronic kidney disease (CKD) face elevated cardiovascular risks.
- Cardiopulmonary fitness, a key prognostic indicator, is underassessed in routine pediatric CKD care.
- Utilizing Z-scores for maximal oxygen uptake (VO2max) can enhance early risk stratification.
Purpose of the Study:
- To assess cardiopulmonary fitness in children with CKD using standardized testing.
- To determine the prevalence of impaired VO2max in this population.
- To identify factors associated with VO2max in pediatric CKD.
Main Methods:
- Prospective, multicenter study involving children aged 6-17 with CKD stages 2-5 (KDIGO classification).
- Standardized cardiopulmonary exercise testing (CPET) was performed, with VO2max expressed as Z-scores.
- Impaired fitness was defined as a VO2max Z-score below -1.64; multivariable regression analyzed determinants of VO2max.
Main Results:
- 77 of 88 enrolled children completed CPET, revealing a mean VO2max Z-score of -1.8±2.1, approximately 10 mL/kg/min lower than reference values.
- 57% of participants exhibited impaired cardiopulmonary fitness.
- VO2max Z-scores declined progressively with increasing CKD stage and were independently associated with hemoglobin, pulmonary function (FEV1), ventilatory efficiency (VE/VCO2 slope), and ventilatory anaerobic threshold (VAT).
Conclusions:
- Children with CKD demonstrate substantially reduced cardiopulmonary fitness, with a notable decline evident even in early disease stages.
- The degree of VO2max impairment is significant and correlates with potentially modifiable clinical and functional factors.
- Early CPET-based screening and tailored, multidisciplinary rehabilitation programs are recommended for pediatric CKD patients.
Key Points:
Children with CKD exhibit markedly lower cardiopulmonary fitness with an absolute maximal oxygen uptake deficit of 10 ml/kg per minute compared with reference values. More than half of the patients show impaired fitness as early as CKD stage 3, highlighting early functional vulnerability. Maximal oxygen uptake is independently associated with modifiable parameters commonly targeted by rehabilitation, supporting tailored intervention strategies.
Background:
Children with CKD are at high cardiovascular risk, yet cardiopulmonary fitness is rarely assessed in routine care. Maximal oxygen uptake (VO 2 max) is a powerful prognostic marker, and Z -score-based evaluations may improve early risk stratification.
Methods:
In this prospective multicenter study, children aged 6-17 years with CKD stages 2-5 (Kidney Disease Improving Global Outcome) underwent standardized cardiopulmonary exercise testing (CPET). VO 2 max was expressed as Z -scores using contemporary pediatric reference values. Impaired fitness was defined as VO 2 max Z -score <-1.64. Multivariable linear regression was used to identify independent determinants of VO 2 max.
Results:
Among 88 enrolled patients (mean age 12±4 years, 67% male), 77 completed a valid CPET. Mean VO 2 max Z -score was -1.8±2.1, corresponding to 33.5±9.2 ml/kg per minute, that is, an absolute lowering of approximately 10 ml/kg per minute compared with age-matched and sex-matched reference values. Overall, 57% had impaired fitness. VO 2 max was progressively lower across higher CKD stages ( P < 0.001 ). In multivariable analysis, higher VO 2 max was independently associated with higher hemoglobin concentration, better pulmonary function (forced expiratory volume in 1 s), better ventilatory efficiency (VE/VCO 2 slope), and higher ventilatory anaerobic threshold, explaining 77% of VO 2 max variability.
Conclusions:
Cardiopulmonary fitness is markedly lower in children with CKD, with a clear stage-dependent decline that is already evident at early disease stages. The magnitude of VO 2 max impairment is substantial and related to potentially modifiable clinical and functional factors, supporting early CPET-based screening and the development of targeted, multidisciplinary rehabilitation in pediatric CKD.
Clinical Trial Registry Name And Registration Number:
Clinicaltrials.gov identifier NCT04897672 and Montpellier University Hospital Institutional Review Board (IRB 202100852).
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