Abstract
Abstract Background: Medical advances in the management of CHD have shifted the focus from childhood mortality to life-long morbidity; therefore, clinical research in paediatric cardiology tends to replace mortality outcomes with functional and patient-reported outcomes. Despite these advances, the stratification of disease severity using a simple and reproducible CHD classification has not been established. The aim was to determine which classification best predicts functional status in children with CHD, in terms of cardiopulmonary fitness. Method: This retrospective cohort study was assessed from a cohort study of 296 children (mean age 11.3 ± 3.1 years, 129 female), who underwent a baseline and final cardiopulmonary exercise tests with a mean follow-up of 4.1 ± 1.6 years. Results: Seven CHD classifications were identified, assessing anatomical, physiological, therapeutic, or functional parameters in foetal, paediatric, or adult CHD populations. The four-stage paediatric CHD disease severity classification established by Uzark et al. best predicted functional status at the final cardiopulmonary exercise test assessment, with an area under the receiver operating characteristics curves of 0.62 (0.55–0.69) for impaired cardiopulmonary fitness (maximum oxygen uptake (VO 2max ) or ventilatory anaerobic threshold < −1.64 Z-score). The best inter-judge classification agreement was also observed for Uzark classification, with a Kappa coefficient of 0.88 (0.78–0.98). Conclusion: The CHD classification by Uzark is reliable in terms of functional status prediction and reproducibility in children with CHD. This simple classification may contribute to identifying children with CHD most at risk of cardiopulmonary fitness impairment and initiating early preventive cardiovascular interventions in paediatric cardiology.