Patient characteristics
| Diagnosis | Subjects n | Sex F/M n | Age yrs |
| IPAH | 16 | 13/3 | 48 (20–77) |
| PAH associated with collagen vascular disease | 24 | 19/5 | 62 (30–76) |
| Scleroderma | 13 | 9/4 | 63 (37–76) |
| Systemic lupus erythematosus | 3 | 3/0 | 51 (44–63) |
| Rheumatoid arthritis | 4 | 3/1 | 59 (30–73) |
| Mixed connective tissue disease | 3 | 3/0 | 68 (63–72) |
| Dermatomyositis | 1 | 1/0 | 69 |
| Others | 4 | 3/1 | 38 (20–58) |
| Portopulmonary hypertension | 1 | 1/0 | 34 |
| Eisenmenger syndrome | 2 | 2/0 | 50 (41–58) |
| Congenital peripheral pulmonary stenosis | 1 | 1/0 | 20 |
| Total | 44 | 35/9 | 55 (20–77) |
| Controls/Wolff–Parkinson–White syndrome | 20 | 8/12 | 39 (19–63) |
Data are presented as mean (range), unless otherwise indicated. F: female; M: male; IPAH: idiopathic pulmonary arterial hypertension; PAH: pulmonary arterial hypertension.