Peripheral muscle characteristics of the study population
| IPAH (n=10) | Controls (n=10) | p Value | |
| Morphology | |||
| Thigh muscle CSA (cm2) | 79 (69–82) | 86 (74–96) | 0.15 |
| Fibre typing (%) | |||
| Type I | 34 (27–49) | 50 (47–53) | 0.05 |
| Type IIa | 27 (21–41) | 29 (27–30) | 0.81 |
| Type IIx | 31 (21–41) | 21 (20–23) | 0.18 |
| Fibre type surface area (μm2) | |||
| Type I | 5125 (3647–5492) | 3811 (3401–6693) | 0.92 |
| Type II | 4235 (3033–5262) | 2702 (2606–3304) | 0.06 |
| Capillarity (n) | |||
| Capillaries/fibres type I | 2.16 (1.78–2.34) | 2.35 (2.10–2.89) | 0.24 |
| Capillaries/fibres type II | 1.85 (1.46–2.10) | 1.75 (1.65–2.01) | 0.73 |
| Enzymatic activity and discriminative ratios | |||
| CS (μmol/g/min) | 11.8 (11.1–15.4) | 13.3 (12.8–15.1) | 0.13 |
| HADH (μmol/g/min) | 4.7 (3.6–5.7) | 5.2 (4.5–6.3) | 0.20 |
| PFK (μmol/g/min) | 62.5 (51.5–72.5) | 51.5 (40.9–61.1) | 0.11 |
| PFK/CS ratio | 5.0 (3.9–6.2) | 3.9 (2.5–4.6) | 0.10 |
| PFK/HADH ratio | 15.0 (8.9–17.0) | 9.1 (5.5–11.3) | 0.05 |
Values are median (IQR).
CS, citrate synthase; CSA, cross-sectional area; HADH, 3-hydroxyacyl-CoA-dehydrogenase; IPAH, idiopathic pulmonary arterial hypertension; PFK, phosphofructokinase.