Table 2: Hemodynamic characteristics in patients with pulmonary hypertension (mod. [8]).

Definition Characteristics Etiology Pulmonary PAPm ≥ 25 mmHg all   Hypertension (PH) CO normal or reduced   PAPm ≥ 25 mmHg PCWP ≤ 15 mmHg CO normal or reduced Group 1: Pulmonary artery hypertension (IPAH) Precapillary PH Group 3: PH with pulmonary diseases and/or hypoxemia   Group 4: CTEPH   Group 5: PH with unclear or multifactorial mechanisms   PAPm ≥ 25 mmHg   Postcapillary PH PCWP > 15 mmHg Group 2: PH with left-heart diseases   CO normal or reduced   (a) passive TPG ≤ 12 mmHg   (b) reactive TPG > 12 mmHg

PAPm: mean pulmonary arterial pressure; CO: cardiac output; PCWP: pulmonary capillary wedge pressure; TPG: transpulmonary gradient (= PAPm − PCWP).