Pulmonary arterial hypertension (PAH) is a progressive and life-limiting condition, making early detection and treatment vital. The symptoms are often non-specific and the condition is frequently confused for other more common diseases.
This page will explore and investigate the options to diagnose PAH, describing the European Society of Cardiology (ESC)/European Respiratory Society (ERS) diagnostic algorithm and the different investigations that can help diagnosis, including echo and right heart catheterisation (RHC).
This page is intended for healthcare providers. Are you a patient? Visit PH-human to find more information about PAH.
Early diagnosis of PAH and timely therapeutic intervention is associated with improved patient outcomes. However, early diagnosis of PAH is often challenging due to the non-specific nature of early symptoms, among other factors. See below for detailed guidance on the diagnostic process for PAH.
PAH should be considered in the differential diagnosis of patients presenting with a constellation of symptoms, including exertional dyspnoea, syncope, angina and/or progressive limitation of exercise capacity. This is of particular concern in patients without apparent risk factors or symptoms/signs of common cardiovascular and respiratory disorders.
Special awareness should be directed towards patients with associated conditions and/or risk factors for the development of PAH, including:
• Family history
• Connective tissue disease
• Congenital heart disease
• HIV infection
• Portal hypertension
• A history of drug or toxin intake known to induce PAH
Adapted from Humbert et al. 2022
Clinical history, , electrocardiograms (ECG), chest radiographs, echocardiograms, pulmonary function tests (PFT), computed tomography (CT) of the chest and ventilation/perfusion (V/Q) scans are all necessary to exclude the diagnosis of PAH due to left heart disease or lung disease, or chronic thromboembolic pulmonary hypertension (CTEPH):
ECGs may provide suggestive or supportive evidence of PH by demonstrating right ventricular (RV) hypertrophy, RV strain, right axis deviation, P pulmonale and QTc prolongation.
Chest radiographs may show evidence of right atrium, right ventricle and pulmonary artery enlargement. They may also show signs of the underlying disease (e.g. lung disease).
Pulmonary function tests and arterial blood gas samples may help identify the contribution of underlying airway or parenchymal lung disease.
CT imaging can provide information such as pulmonary arterial diameter and clues as to the type of PAH (e.g. cardiac abnormalities). High-resolution CT provides detailed views of the lung parenchyma, helping determine the cause of PH when there are features of parenchymal lung disease.
A V/Q lung scan is used to exclude CTEPH. Where there is evidence of multiple segmental perfusion defects, a diagnosis of CTEPH should be suspected. The final diagnosis of CTEPH requires CT pulmonary angiography and RHC.
Learn more about PAH, including its clinical classification and various subtypes.
Find out about the different screening strategies used in at-risk patients. Patients with suspected PAH should be referred to a specialist centre for further investigation.
ABG, arterial blood gas; CT, computed tomography; CTEPH, chronic thromboembolic pulmonary hypertension; DLCO, carbon monoxide diffusing capacity; ECG, electrocardiogram; EOV, exercise oscillatory ventilation; ERS, European Respiratory Society; ESC, European Society of Cardiology; HIV, human immunodeficiency virus; HPAH, heritable pulmonary arterial hypertension; IPAH, idiopathic pulmonary arterial hypertension; LVEI, left ventricle eccentricity index; PaCO2, partial pressure of arterial carbon dioxide; PAH, pulmonary arterial hypertension; PaO2, partial pressure of arterial oxygen; PETCO2, end-tidal partial pressure of carbon dioxide; PFT, pulmonary function test; PH, pulmonary hypertension; PVOD, pulmonary veno-occlusive disease; RHC, right heart catheterisation; RV, right ventricular; RVOT AT, right ventricular outflow tract acceleration time; sPAP, systolic pulmonary arterial pressure; SPECT, single-photon emission computed tomography; SSc, systemic sclerosis; TAPSE, tricuspid annular plane systolic excursion; TRV, tricuspid regurgitation velocity; VE/VCO2, ventilatory equivalent for carbon dioxide; V/Q, ventilation/perfusion