What is Pulmonary Arterial Hypertension?
Pulmonary arterial hypertension (PAH) is a clinical condition characterised by the presence of elevated blood pressure in the pre-capillary pulmonary circulation, without any other cause of pulmonary hypertension (PH), for example: due to lung disease, chronic thromboembolic pulmonary hypertension, or other rare diseases.2
Specifically, the haemodynamic definition of PAH is as follows:1,2
- mPAP >25 mmHg*
- PAWP ≤15 mmHg
- PVR ≥3 WU
*At the World Symposium of Pulmonary Hypertension (WSPH) meeting in December 2018, Simonneau and colleagues from the 6th WSPH Taskforce proposed changing the upper limit of normal mPAP to 20 mmHg.1 In Australia, in order to access PBS funding for PAH therapy, the mean pulmonary artery pressure (mPAP) should be ≥ to 25mmHg.
mPAP=mean pulmonary arterial pressure; PAWP=pulmonary arterial wedge pressure; PVR=pulmonary vascular resistance.
PAH is uncommon3
Prognosis of untreated PAH is poor5
PAH is just one type of PH2
As well as being split into subtypes based on specific aetiology, PAH forms 1 of 5 Groups of PH, which are separated and organised according to clinical presentation, pathological findings, haemodynamic characteristics and treatment strategy.2