Close
18th February 2025
Overview of pulmonary hypertension
Pulmonary hypertension (PH) is an umbrella term for the pathological condition of raised pressures in the pulmonary vasculature and encompasses numerous aetiological origins. The diagnosis and identification of the underlying cause is vital as it determines the available treatment options.
Classification of PH is into five categories, as per the World Health Organisation (WHO).
Additional categorisation is based on haemodynamic profile, namely whether the disease of the pulmonary vasculature is primarily pre-capillary, post-capillary or combined pre- and post-capillary in origin. Irrespective of the origin, the overarching diagnostic criteria for PH is mean pulmonary artery pressure (mPAP) of >20 mmHg at rest.
Classification of pulmonary hypertension
| Group | Causes |
|---|---|
| I – Pulmonary arterial hypertension (PAH) | Idiopathic
Inherited Drug or toxin induced Associated with other conditions, e.g. connective tissue disease, portal hypertension Pulmonary veno-occlusive disease Persistent PH of the newborn |
| II – PH due to left heart disease | Heart failure with reduced or preserved ejection fraction
Valvular heart disease, e.g. mitral stenosis, mitral regurgitation Congenital/acquired cardiovascular conditions leading to post-capillary PH |
| III – PH due to lung disease and/or hypoxia | Chronic obstructive lung disease
Interstitial lung disease Other lung disease with a mixed obstructive/restrictive pattern Hypoxia without lung disease, e.g. sleep disordered breathing, chronic exposure to high altitudes Developmental lung disorders |
| IV – PH due to pulmonary artery obstruction | Chronic thromboembolic PH (CTEPH)
Other causes of arterial obstruction, e.g. tumours, parasites |
| V – PH with unclear and/or multifactorial mechanisms | Haematological disorders, e.g. chronic haemolytic anaemias, myeloproliferative neoplasms
Systemic or metabolic disorders, e.g. sarcoidosis, neurofibromatosis, glycogen storage disease Complex congenital heart disease |
Table 4 WHO classification of pulmonary hypertension
Cor pulmonale
Cor pulmonale describes the PH-induced structural alteration of the right ventricle (e.g. hypertrophy) associated with chronic lung disease and/or hypoxaemia (i.e. group III PH). Elevation of pulmonary vascular resistance increases pulmonary arterial pressure, which increases right ventricular afterload, resulting in right ventricular dysfunction and failure.
Complete Guide to Clinical Genetics ST3 Application and Recruitment (2027)
Written by Medibuddy. Last updated: October 2026. Clinical Genetics is
Complete Guide to Clinical Radiology ST3 Application and Recruitment (2027)
Recruitment paused: NHS England is not running Clinical Radiology ST3+ recru
Complete Guide to Paediatric Surgery ST3 Application and Recruitment in United Kingdom (2026)
Written by Medibuddy. Last updated: October 2026. If you’re planning
Take your subscriptions with you
Our mobile app allows you to access your interview and exam question banks wherever you are.
