Peak Work Rate Increases With Lower Extremity‐Focused Exercise Training in Adolescents With Fontan Circulation

Abstract

Background Skeletal muscle deficits are associated with worse exercise performance in the Fontan circulation and may be improved by exercise training. We aimed to assess the change in leg lean mass (a marker of skeletal muscle), exercise performance, and functional health status after a lower extremity‐focused exercise intervention in adolescents with Fontan circulation. Methods and Results Densitometry for measurement of leg lean mass, cardiopulmonary exercise test, exercise cardiac magnetic resonance, peripheral vascular testing, physical activity questionnaire, and quality of life assessment were performed at baseline and after a 24‐week, hybrid center‐ and home‐based training program. Leg lean mass Z‐scores were generated, and exercise parameters were expressed as percentage expected based on reference data. The effect of training was assessed by paired t‐tests and simple linear regression. Twenty participants (15.6±1.7 years, 50% male) demonstrated low baseline leg lean mass Z‐scores with no significant improvement with training (−1.38±1.02 pre versus −1.31±1.06 post, P =0.33). Maximum and percent predicted work increased from 121.9±29.8 (0.66±0.12) to 131.3±35.1 (0.70±0.15) watts ( P =0.02). Peak respiratory exchange ratio increased (1.19±0.02 versus 1.25±0.01, P =0.02) but percent predicted oxygen consumption was unchanged, suggesting higher anaerobic activity after training. Physical activity questionnaire score positively associated with peak work at baseline (ß=18.13 [95% CI, 0.83–35.44], R 2 =0.21; P =0.04) but physical activity questionnaire, quality of life scores, exercise cardiac magnetic resonance performance, and peripheral vascular function were unchanged with training. Conclusions Peak work rate and anaerobic activity increased with lower extremity‐focused training in adolescents with Fontan circulation. Larger studies should test the impact of these changes on functional status and quality of life.

Body composition in patients with Fontan physiology: a systematic review

“…Eight out of eighteen studies [5, 18-21, 23, 27] used Z-scores. The studies indexed their results on sex and age [5,18,19], sex, age, race, height, BMI, and leg-length [20][21][22]27] or did not mention how they normalized their results [23].…”

“…After removing duplicates and screening on title and abstract, the full text of 29 articles was screened. A total of 18 studies were included in this systematic review [5,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. This process is presented in Fig.…”

“…In total, body composition was measured in 774 patients with a Fontan circulation, and 298 healthy participants served as controls. Five studies included children only [15,16,24,27,28], five studies included adults only [5,17,18,25,32], and eight studies included both children and adults [19-23, 26, 30, 31]. The mean age of the patients between studies ranged from 1.5 to 30 years; 45.0% of the participants was female.…”

“…Out of the 18 included studies, 17 calculated the BMI of Fontan patients and controls or reference values [5,15,16,[18][19][20][21][22][23][24][25][26][27][28][30][31][32]. These outcomes are documented in Table 3.…”

“…These outcomes are documented in Table 3. Nine studies measured fat mass in patients with a Fontan circulation [5,15,17,19,21,23,25,30,32], and 15 measured lean/muscle mass in patients with a Fontan circulation [5,15,16,[18][19][20][21][22][23][24][25][26][27][28]31]. Outcomes regarding fat, lean, and muscle mass can also be found in Table 3.…”