TABLE 1.

Overview of the haemodynamic definitions of pulmonary hypertension (PH)

Haemodynamic definitions	mPAP	PVR	PAWP
PH	>20 mmHg
Pre-capillary PH	>20 mmHg	>2 WU	≤15 mmHg
Isolated post-capillary PH	>20 mmHg	≤2 WU	>15 mmHg
Combined post- and pre-capillary PH	>20 mmHg	>2 WU	>15 mmHg
Unclassified PH #	>20 mmHg	≤2 WU	≤15 mmHg
Exercise PH	mPAP/CO slope >3 mmHg·min·L−1 between rest and exercise

CO: cardiac output; mPAP: mean pulmonary artery pressure; PAWP: pulmonary artery wedge pressure; PVR: pulmonary vascular resistance. ^#: these patients are frequently characterised by elevated pulmonary blood flow and, although they have PH, they do not fulfil the criteria of pre- or post-capillary PH.