Body Composition and Exercise Performance in Youth With a Fontan Circulation: A Bio-Impedance Based Study

Area of Science:

• Pediatric Cardiology
• Body Composition Analysis
• Exercise Physiology

Background:

• Adults with Fontan circulation often present with myopenia and elevated adiposity.
• Bioelectrical impedance analysis (BIA) is a validated method for assessing body composition, offering an alternative to dual-energy x-ray absorptiometry.
• This study investigates body composition differences in pediatric Fontan patients using BIA.

Purpose of the Study:

• To compare body composition between pediatric patients with Fontan circulation and healthy controls.
• To assess the relationship between muscle mass and exercise capacity in Fontan patients.
• To examine the impact of Fontan operation complications on body composition.

Main Methods:

• Retrospective chart review of patients aged <22 years undergoing cardiopulmonary exercise testing and BIA.
• Comparison of body composition data between 47 Fontan patients and 165 control subjects.
• Analysis of lean body mass, skeletal muscle mass, and body fat percentage using BIA.

Main Results:

• Fontan patients showed significantly lower lean body mass, skeletal muscle mass, and skeletal muscle indexed to height.
• Fontan patients had a higher percentage of body fat compared to controls.
• Increased skeletal muscle mass was strongly associated with higher peak oxygen consumption and oxygen pulse.
• Patients with Fontan complications had lower skeletal muscle mass and higher body fat percentage.

Conclusions:

• The Fontan circulation is associated with significant myopenia and increased adiposity in pediatric patients.
• Higher muscle mass is linked to improved exercise capacity in this population.
• Complications of the Fontan operation are associated with poorer body composition, characterized by reduced muscle and increased fat.