Table 1– Haemodynamic definitions of pulmonary hypertension (PH)
DefinitionCharacteristicsClinical group(s)#
PHpa ≥25 mmHgAll
Pre-capillary PHpa ≥25 mmHg1. PAH
Ppcw ≤15 mmHg3. PH due to lung diseases
CO normal or reduced4. CTEPH
5. PH with unclear and/or multifactorial mechanisms
Post-capillary PHpa ≥25 mmHg2. PH due to left heart disease
Ppcw >15 mmHg
CO normal or reduced
 PassiveTPG ≤12 mmHg
 Reactive (out of proportion)TPG >12 mmHg
  • All values measured at rest. pa: mean pulmonary arterial pressure; Ppcw: pulmonary capillary wedge pressure; CO: cardiac output; TPG: transpulmonary pressure gradient (pa – 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.