Table 1

Simplified risk assessment in pulmonary arterial hypertension

Risk criteriaDeterminants of prognosis*
(estimated 1-year mortality)
Low risk variables
Intermediate risk variables
High risk variables
A.WHO functional classI, IIIIIIV
B.6MWD>440 m165–440 m<165 m
C.NT-pro-BNP/BNP plasma levels or
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
CI ≥2.5 L/min/m2
SvO2 >65%
CI 2.0 to 2.4 L/min/m2
SvO2 60%–65%
CI <2.0 L/min/m2
Individual risk category definitionLow-risk definitionIntermediate-risk definitionHigh-risk definition
At least three low-risk criteria and no high-risk criteriaDefinitions of low or high risk not fulfilledAt 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.