Determinants of prognosis# (estimated 1-year mortality) | Low risk <5% | Intermediate risk 5–10% | High risk >10% |
Clinical signs of right heart failure | Absent | Absent | Present |
Progression of symptoms | No | Slow | Rapid |
Syncope | No | Occasional syncope¶ | Repeated syncope+ |
WHO functional class | I, II | III | IV |
6MWD | >440 m | 165–440 m | <165 m |
Cardiopulmonary exercise testing | Peak V′O2>15 mL·min−1·kg−1 (>65% pred) V′E/V′CO2 slope <36 | Peak V′O2 11–15 mL·min−1·kg−1 (35–65% pred) V′E/V′CO2 slope 36–44.9 | Peak V′O2 <11 mL·min−1·kg−1 (<35% pred) V′E/V′CO2 slope ≥45 |
NT-proBNP plasma levels | BNP <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 |
Haemodynamics | RAP <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; V′O2: oxygen uptake; V′E/V′CO2: 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.