Baseline characteristics of the study population
| Demographic characteristics | Fontan subjects (n=10) | Controls (n=10) | P value |
| Age (years) | 24.5 (20.8–34.0) | 30.5 (27.5–43.3) | 0.075 |
| Male sex | 5 (50) | 5 (50) | >0.999 |
| BMI (kg/m2) | 23.0 (21.0–27.0) | 22.0 (20.8–25.0) | 0.761 |
| Age at Fontan procedure (years) | 2.0 (2.0–7.5) | – | – |
| Indexed CMR flows (L/min/m2) | |||
| SVC | 0.72 (0.55–0.93) | 1.05 (0.97–1.15) | 0.006 |
| Fontan/Sup-IVC | 1.75 (1.67–2.07) | 2.10 (1.97–2.38) | 0.031 |
| Sub-IVC | 0.99 (0.80–1.37) | 1.33 (1.17–1.47) | 0.049 |
| HV | 0.81 (0.62–1.03) | 0.79 (0.74–1.03) | 0.734 |
| PoV | 0.51 (0.37–0.60) | 0.59 (0.51–0.78) | 0.104 |
| PBF | 2.48 (2.33–2.99) | 3.37 (3.09–3.81) | 0.007 |
| CO | 2.88 (2.28–3.35) | 2.97 (2.76–3.42) | 0.345 |
| Cardiopulmonary function tests* | |||
| Resting oxygen saturation (%) | 98 (90–99) | – | – |
| Spirometry | – | – | |
| FEV1 (absolute, L) | 2.99 (2.01–3.49) | ||
| FEV1 (% predicted) | 71 (55–79) | ||
| FVC (absolute, L) | 3.41 (2.34–4.13) | ||
| FVC (% predicted) | 63 (56–80) | ||
| FEV1/FVC (absolute) | 86 (81–86) | ||
| FEV1/FVC (% predicted) | 100 (95–107) | ||
| Peak VO2 | – | – | |
| Absolute (cc/kg/min) | 22.1 (17.8–25.0) | ||
| % predicted | 53 (46–68) | ||
| VO2 at anaerobic threshold (% of peak predicted) | 37 (34–49) | – | – |
| VE/VCO2 at anaerobic threshold | 34 (30–43) | – | – |
| Peak RER | 1.07 (1.04–1.16) | – | – |
Data expressed as median (IQR) and absolute number (%).
*Cardiopulmonary function tests within 6 months of study entry are shown.
BMI, body mass index; CMR, cardiovascular magnetic resonance; CO, cardiac output; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; HV, hepatic vein; PBF, pulmonary blood flow; PoV, portal vein; RER, respiratory exchange ratio; Sub-IVC, subhepatic inferior vena cava; Sup-IVC, suprahepatic inferior vena cava; SVC, superior vena cava; VE/VCO2, ventilatory efficiency; VO2, oxygen consumption.