TABLE 1

Risk assessment in patients with pulmonary arterial hypertension

Determinants of prognosis#
(estimated 1-year mortality)
Low risk <5%Intermediate risk 5–10%High risk >10%
Clinical signs of right heart failureAbsentAbsentPresent
Progression of symptomsNoSlowRapid
SyncopeNoOccasional syncopeRepeated syncope+
WHO functional classI, IIIIIIV
6MWD>440 m165–440 m<165 m
Cardiopulmonary exercise testingPeak VO2>15 mL·min−1·kg−1
(>65% pred)
VE/VCO2 slope <36
Peak VO2 11–15 mL·min−1·kg−1
(35–65% pred)
VE/VCO2 slope 36–44.9
Peak VO2 <11 mL·min−1·kg−1
(<35% pred)
VE/VCO2 slope ≥45
NT-proBNP plasma levelsBNP <50 ng·L−1
NT-proBNP <300 ng·L−1
BNP 50–300 ng·L−1
NT-proBNP 300–1400 ng·L−1
BNP >300 ng·L−1
NT-proBNP>1400 ng·L−1
Imaging (echocardiography, CMR imaging)RA area <18 cm2
No pericardial effusion
RA area 18–26 cm2
No or minimal, pericardial effusion
RA area >26 cm2
Pericardial effusion
HaemodynamicsRAP <8 mmHg
CI ≥2.5 L·min−1·m−2
SvO2 >65%
RAP 8–14 mmHg
CI 2.0–2.4 L·min−2·m−2
SvO2 60–65%
RAP >14 mmHg
CI <2.0 L·min−1·m−2
SvO2 <60%
  • WHO: World Health Organization; 6MWD: 6-min walking distance; NT-proBNP: N-terminal pro-brain natriuretic peptide; CMR: cardiac magnetic resonance; VO2: oxygen uptake; VE/VCO2: ventilatory equivalents for carbon dioxide; BNP: brain natriuretic peptide; RA: right atrium; RAP: right atrial pressure; CI: cardiac index; SvO2: mixed venous oxygen saturation. #: most of the proposed variables and cut-off values are based on expert opinion. They may provide prognostic information and may be used to guide therapeutic decisions, but application to individual patients must be done carefully. One must also note that most of these variables have been validated mostly for idiopathic pulmonary arterial hypertension and the cut-off levels used above may not necessarily apply to other forms of pulmonary arterial hypertension. Furthermore, the use of approved therapies and their influence on the variables should be considered in the evaluation of the risk. : occasional syncope during brisk or heavy exercise, or occasional orthostatic syncope in an otherwise stable patient. +: repeated episodes of syncope, even with little or regular physical activity. Reproduced from [7] with permission from the publisher.