Definition | Characteristics | Clinical group(s)# |
PH | P̄pa ≥25 mmHg | All |
Pre-capillary PH | P̄pa ≥25 mmHg | 1. PAH |
Ppcw ≤15 mmHg | 3. PH due to lung diseases | |
CO normal or reduced¶ | 4. CTEPH | |
5. PH with unclear and/or multifactorial mechanisms | ||
Post-capillary PH | P̄pa ≥25 mmHg | 2. PH due to left heart disease |
Ppcw >15 mmHg | ||
CO normal or reduced¶ | ||
Passive | TPG ≤12 mmHg | |
Reactive (out of proportion) | TPG >12 mmHg |
All values measured at rest. P̄pa: mean pulmonary arterial pressure; Ppcw: pulmonary capillary wedge pressure; CO: cardiac output; TPG: transpulmonary pressure gradient (P̄pa – mean Ppcw); PAH: pulmonary arterial hypertension; CTEPH: chronic thromboembolic PH. #: according to table 3; ¶: high CO can be present in cases of hyperkinetic conditions, such as systemic-to-pulmonary shunts (only in the pulmonary circulation), anaemia and hyperthyroidism, etc.