| Determinants of risk | Lower risk | Higher risk |
| Clinical evidence of RV failure | No | Yes |
| Progression of symptoms | No | Yes |
| Syncope | No | Yes |
| Growth | Failure to thrive | |
| WHO functional class | I, II | III, IV |
| BNP/NT-proBNP | Minimally elevated | Significantly elevated, increasing |
| Echocardiography | Severe RV enlargement/dysfunction Pericardial effusion | |
| Haemodynamics | Systemic CI >3.0 L·min−1·m−2 | Systemic CI <2.5 L·min−1·m−2 |
| mPAP/mSAP <0.75 mmHg | mPAP/mSAP >0.75 mmHg | |
| Acute vasoreactivity | RAP >10 mmHg PVRI >20 WU·m−2 |
RV: right ventricular; WHO: World Health Organization; BNP: B-type natriuretic peptide; NT-proBNP: N-terminal pro-BNP; CI: cardiac index; mPAP: mean pulmonary artery pressure; mSAP: mean systemic artery pressure; RAP: right atrial pressure; PVRI: pulmonary vascular resistance index; WU: Wood unit. Reproduced from [18] with permission from the publisher.