Variables and cut-off values used for risk stratification
| Low risk | Intermediate risk | High risk | |
| WHO FC | I/II | III | IV |
| 6-min walking distance m | >440 | 165–440 | <165 |
| BNP ng·L−1 | <50 | 50–300 | >300 |
| NT-proBNP ng·L−1 | <300 | 300–1400 | >1400 |
| Right atrial pressure mmHg | <8 | 8–14 | >14 |
| Cardiac index L·min−1·m−2 | ≥2.5 | 2.0–2.4 | <2.0 |
| SvO2% | >65 | 60–65 | <60 |
WHO FC: World Health Organization functional class; BNP: brain natriuretic peptide; NT-proBNP: N-terminal fragment of pro-brain natriuretic peptide; SvO2: mixed venous oxygen saturation.