Background: Peak oxygen uptake (peak VO2) and its decline predict death or serious cardiovascular adverse events in patients with Fontan circulation. Our aim was to study VO2 in a population of Fontan patients with variable age and contemporary surgical correction, and find predictors of functional status which could lead to management changes.
Methods: Prospective cardiopulmonary exercise test was performed on a treadmill. Blood tests and transthoracic echocardiogram were performed on the same day. Dependent variables were defined as: VO2 at ventilatory threshold (VT) as a percentage of the predicted peak VO2 and peak VO2 as a percentage of its predicted value. Statistical analysis was performed on SPSS® version 23 and significance was defined as a p-value < 0.05.
Results: Forty-eight patients were included for analysis. All had a lateral or extracardiac conduit. Mean age was 18.2 years (SD 6.2). Mean age at Fontan completion of 6.5 years (SD 2.3) showed no association with functional capacity. Mean percent VO2 at VT was 37.6% (SD 9.4) and percent peak VO2 was 67.8% (SD 16.7). VO2 both at ventilatory threshold and peak was associated with age, weekly sports practice, significant atrioventricular regurgitation and having a pacemaker or being on antiarrhythmic drugs. On multivariate analysis, weekly sports practice was the best predictor for VO2 values.
Conclusions: Sports practice is a modifiable factor that significantly impacts functional capacity in Fontan patients despite their age. Clinicians should actively prescribe and promote physical activity in this population, either with regular sports practice or engagement in cardiac rehabilitation programs.
Keywords: Cardiopulmonary exercise test; Congenital heart disease; Echocardiography; Exercise; Fontan procedure; Sports practice.
Copyright © 2019 Elsevier B.V. All rights reserved.