Table 2. Variables with established importance for assessing disease severity, stability and prognosis in pulmonary arterial hypertension.
| Determinants of prognosis | Better prognosis | Worse prognosis |
| Clinical evidence of RV failure | No | Yes |
| Rate of progression of symptoms | Slow | Rapid |
| Syncope | No | Yes |
| WHO-FC | I, II | IV |
| 6MWD | Longer (>500 m)¶ | Shorter (<300 m) |
| Cardiopulmonary exercise testing | Peak O2 consumption >15 mL·min−1·kg−1 | Peak O2 consumption <12 mL·min−1·kg−1 |
| BNP/NT-proBNP plasma levels | Normal or near-normal | Very elevated and rising |
| Echocardiographic findings# | No pericardial effusion TAPSE >2.0 cm | Pericardial effusion TAPSE <1.5 cm |
| Haemodynamics | Pra <8 mmHg and CI ≥2.5 L·min−1·m−2 | Pra >15 mmHg or CI ≤2.0 L·min−1·m−2 |
RV: right ventricular; WHO-FC: World Health Organization functional class; 6MWD: 6-min walk distance; BNP: brain natriuretic peptide; NT-proBNP: N-terminal proBNP; TAPSE: tricuspid annular plane systolic excursion; Pra: right atrial pressure; CI: cardiac index. #: TAPSE and pericardial effusion have been selected because they can be measured in the majority of patients; ¶: depending on age. Reprinted from [46] with permission from the publisher.