Clinical definition and classification
Pulmonary hypertension (PH) simply represents an elevated mean pulmonary artery pressure ≥ 25 mmHg measured at right heart catheterisation. This can be a consequence of pulmonary arterial hypertension (PAH) or other conditions such as left-sided heart disease or hypoxic lung disease.
Definition
Pulmonary arterial hypertension (PAH) is caused by a progressive increase in pulmonary vascular resistance (PVR) leading to right ventricular failure and premature death. The condition is diagnosed at right heart catheterisation by:
– sustained elevation of mean pulmonary arterial pressure to ≥25 mmHg AND.
– a mean pulmonary artery occlusion pressure of ≤15 mmHg AND.
– a pulmonary vascular resistance (PVR) >3 Wood units (WU).
in the absence of other causes of precapillary PH.
Classification
The classification of conditions leading to pulmonary hypertension is clinically based and was last defined in the ESC/ERS guidelines in 2015. The major classes are as follows:
1. Pulmonary arterial hypertension.Pulmonary arterial hypertension.
1A. Pulmonary veno-occlusive disease and/or pulmonary capillary haemangiomatosis .
1B. Persistent pulmonary hypertension of the newborn.
2. Pulmonary hypertension due to left heart disease.
3. Pulmonary hypertension due to lung diseases and/or hypoxia.
4. Chronic thromboembolic pulmonary hypertension and other pulmonary artery obstructions.
5. Pulmonary hypertension with unclear and/or multifactorial mechanisms.
Detailed ERS table is available here