Exercise Capacity, Muscle Mass, and Quality of Life in Pediatric Patients with Fontan Circulation

To examine how measures of cardiac, vascular, and muscle health relate to Pediatric Quality of Life Inventory ^TM (PedsQL) score in a cohort of children and adolescents with Fontan circulation.

We performed a cross-sectional analysis of baseline data from children and adolescents (8-19 years) with Fontan circulation enrolled in a prospective study. Participants underwent a series of tests, including a cardiopulmonary exercise test, dual-energy X-ray absorptiometry measures of appendicular lean mass index (ALMI, kg/m²), leg dynamometry, and the 23-item PedsQL. The survey quantifies Physical, Emotional, Social, and School functioning into 1 total score and 2 summary scores for physical and psychosocial health.

135 patients (median age 12.7 [IQR 10.2, 15.6] years) completed the baseline visit. Median time from Fontan operation was 8.7 years [IQR 5.9, 12.0]. Peak VO₂ was 1309 [IQR 1070, 1670] mL/min, and indexed peak VO₂ was 31.1 [IQR 25.2, 36.1] mL/kg/min. Physical and Psychosocial PedsQL summary scores were 78.1 [IQR 67.2,90.6] and 76.7 [IQR 63.3, 90], respectively, and the total score was 76.1 [IQR 65.2, 88.0]. Absolute peak VO₂ was weakly correlated with PedsQL Physical Summary Score (ρ=0.21, P=0.015), but indexed peak VO2, % predicted peak VO2, and Fontan-specific peak VO2 z-score were not ALMI z-score was -0.84 [IQR -1.56, -0.14] and positively correlated with total PedsQL score (ρ=0.28, P=0.001) and the Physical Functioning domain (ρ=0.30, P<0.001).

Skeletal muscle mass was associated with quality of life in children with Fontan circulation. The association between VO2 and physical function was attenuated with body-size normalization.