Important definitions
| PH is a haemodynamic and pathophysiological condition defined as an increase in P̄pa ≥25 mmHg at rest as assessed by right heart catheterisation (table 3). PH can be found in multiple clinical conditions (table 4). |
| The definition of PH on exercise as a P̄pa >30 mmHg as assessed by right heart catheterisation is not supported by published data. |
| PAH (group 1) is a clinical condition characterised by the presence of pre-capillary PH (table 3) in the absence of other causes of pre-capillary PH such as PH due to lung diseases, chronic thromboembolic PH, or other rare diseases (table 4). PAH includes different forms that share a similar clinical picture and virtually identical pathological changes of the lung microcirculation (table 4). |
PH: pulmonary hypertension; P̄pa: mean pulmonary arterial pressure; PAH: pulmonary arterial hypertension.