Simplified risk assessment in pulmonary arterial hypertension
| Risk criteria | Determinants of prognosis* (estimated 1-year mortality) | Low risk variables (<5%) | Intermediate risk variables (5%–10%) | High risk variables (>10%) |
| A. | WHO functional class | I, II | III | IV |
| B. | 6MWD | >440 m | 165–440 m | <165 m |
| C. | NT-pro-BNP/BNP plasma levels or RAP | BNP <50 ng/L NT-pro-BNP <300 ng/L or RAP <8 mm Hg | BNP 50–300 ng/L NT-pro-BNP 300–1400 ng/L or RAP 8–14 mm Hg | BNP >300 ng/L NT-pro-BNP >1400 ng/L or RAP >14 mm Hg |
| D. | CI or SvO2 | CI ≥2.5 L/min/m2 or SvO2 >65% | CI 2.0 to 2.4 L/min/m2 or SvO2 60%–65% | CI <2.0 L/min/m2 or SvO2<60% |
| Individual risk category definition | Low-risk definition | Intermediate-risk definition | High-risk definition | |
| At least three low-risk criteria and no high-risk criteria | Definitions of low or high risk not fulfilled | At least two high-risk criteria including CI or SvO2 | ||
*Most of these variables have been validated mostly for IPAH and the cut-off levels used above may not necessarily apply to other forms of PAH.
BNP, brain natriuretic peptide; CI, cardiac index; IPAH, idiopathic PAH; 6MWD, 6 min walk distance; NT-pro-BNP, N-terminal pro-brain natriuretic peptide; PAH, pulmonary arterial hypertension; RAP, right atrial pressure; SvO2, mixed venous oxygen saturation; WHO, World Health Organization.