Definition and diagnosis of pulmonary hypertension

Pulmonary hypertension is defined as a mean pulmonary artery pressure of more than 20 mmHg at rest, recorded during right heart catheterisationSimonneau, 2019. It is often incidentally detected by echocardiography.

Echocardiography usually reports the systolic pulmonary artery pressure rather than the mean pressure, and overestimates pulmonary hypertension, especially in high cardiac output states. If systolic pulmonary artery pressure is more than 40 mmHg, further investigation (initially with echocardiography) is required to exclude other causes, such as heart failure, chronic obstructive pulmonary disease, pulmonary embolism or sleep apnoea.

Refer patients with pulmonary hypertension, especially those who have symptoms, to a specialised clinic for assessment of aetiology (including reversible causes) and disease severity, which determines the appropriate therapy. Right heart catheterisation is required to confirm the diagnosis of pulmonary arterial hypertension before considering specific therapies.