Cardiopulmonary Exercise Testing in a Pediatric Fontan Cohort.

Area of Science:

• Pediatric Cardiology
• Cardiovascular Physiology
• Exercise Science

Background:

• The Fontan procedure is a palliative surgery for complex single-ventricle congenital heart defects.
• Long-term outcomes after Fontan palliation can be variable, necessitating methods to assess prognosis.
• Cardiopulmonary exercise testing (CPET) provides valuable physiological data for risk stratification.

Purpose of the Study:

• To investigate the association between CPET variables and transplant-free survival in pediatric Fontan patients.
• To identify specific CPET parameters that predict adverse cardiovascular events (CAEs) in this population.

Main Methods:

• Retrospective review of 118 patients (≤18 years) who underwent a Fontan procedure and subsequent CPET between 2004-2022.
• Serial CPET analysis was conducted for patients with tests at least one year apart.
• Univariable regression analysis was used to identify predictors of CAEs (mortality or cardiac transplantation).

Main Results:

• Baseline peak oxygen uptake (VO2peak) was 74.6% of expected, indicating mild depression in exercise capacity.
• Exercise capacity showed a yearly decline of 1.36% in expected peak oxygen uptake.
• Exercise duration and percent of age-predicted maximal heart rate achieved were significantly associated with CAEs.

Conclusions:

• Pediatric Fontan patients exhibit mildly reduced exercise capacity in adolescence, which progressively declines.
• Exercise duration and percentage-predicted maximal heart rate are significant predictors of adverse cardiovascular events in Fontan survivors.