Table 1

Pulmonary hypertension: classification, epidemiology, haemodynamic characteristics, and treatments

Classification*EpidemiologyHaemodynamic characteristics†Treatment
Group 1‡
Idiopathic PAH
Heritable PAH
PAH induced by drugs or toxins
PAH associated with:
connective tissue disease, HIV infection, portal hypertension, congenital heart disease, schistosomiasis, pulmonary veno-occlusive disease-pulmonary capillary haemangiomatosis, persistent PH of the newborn
Incidence of 1.1-7.5 patients/million adults/year.
Prevalence of 6.6-26.0 patients/million adults.3
Estimated >200 million people infected worldwide with Schistosoma276; prevalence of Schistosoma PH understudied
Precapillary PH:
mPAP >20 mm Hg
PAWP ⩽15 mm Hg
PVR ⩾3 Woods units†
Pulmonary vasodilators
(phosphodiesterase type 5 inhibitors, endothelin receptor antagonists, soluble guanylate cyclase, prostacyclin and prostacyclin analogues, calcium channel blockers in responders to acute vasodilator challenge)
Group 2‡
Heart failure with preserved LVEF
Heart failure with reduced LVEF
Valvular heart disease
Congenital or acquired cardiovascular conditions leading to postcapillary PH
Most common form of PH, accounting for 65-80% of patients with 3PH
PH affects >50% of patients with left ventricular heart failure277
Postcapillary PH
mPAP >20 mm Hg
PAWP >15 mm Hg
PVR <3 Woods units
Or combined precapillary and postcapillary PH
mPAP >20 mm Hg
PAWP >15 mm Hg
PVR 3 Woods units
Treat left heart disease
Maintain euvolaemia with diuretics, sodium, and fluid restriction
Control systemic hypertension
Group 3‡
Obstructive lung disease (ie, COPD-PH, OSA)
Restrictive lung disease (ie, ILD-PH)
Other lung disease with mixed restrictive or obstructive pattern
Hypoxia without lung disease including high altitude
Developmental lung disorders
Second most common form of PH after left heart disease3
5-25% of patients with mild to moderate COPD; up to 90% in patients with severe COPD278 279
38-80% in advanced idiopathic pulmonary fibrosis280–282
Precapillary PH:
mPAP >20 mm Hg
PAWP ⩽5 mm Hg
PVR ⩾3 Woods units†
Treat underlying disease
Supplemental oxygen or non-invasive positive pressure ventilation, or both, to maintain SpO2 ⩾90% and PaCO2 ⩽ 40 mm Hg
Inhaled trepostinil (approved for ILD-PH only)
Group 4‡
Chronic thromboembolic PH
Malignant and non-malignant tumours
Arteritis without connective tissue disease
Congenital pulmonary artery stenosis
Parasites (hydatidosis)
Incidence of 2-6 and prevalence of 26-38 patients/million adults283–285Precapillary PH:
mPAP >20 mm Hg
PAWP ⩽15 mm Hg
PVR ⩾3 Woods units†
Treat underlying disease
For chronic thromboembolic PH:
Pulmonary thromboendarterectomy
Balloon pulmonary angioplasty
Pulmonary vasodilators (soluble guanylate cyclase)
Group 5‡
Haematological disorders
Systemic and metabolic disorders
Chronic renal failure
Fibrosing mediastinitis
Complex congenital heart disease
Mostly unknown
Prevalence of PH in sarcoidosis 6-20% at rest and up to 43% with exercise286
Predominantly precapillary PH, but includes postcapillary and combined pre- and postcapillary PHTreat underlying disease
Pulmonary vasodilator treatment can be used off label in some patients
  • COPD=chronic obstructive pulmonary disease; COPD-PH=pulmonary hypertension related to COPD; ILD-PH=pulmonary hypertension related to interstitial lung disease; LVEF=left ventricular ejection fraction; mPAP=mean pulmonary arterial pressure; OSA=obstructive sleep apnoea; PaCO2=partial pressure of carbon dioxide in arterial blood; PAH=arterial hypertension; PAWP=pulmonary arterial wedge pressure; PH=pulmonary hypertension; PVR=pulmonary vascular resistance; SpO2=arterial oxygen saturation measured by pulse oximeter.

  • *According to the Sixth World Symposium on Pulmonary Hypertension.

  • †Defined by Sixth World Symposium on Pulmonary Hypertension, 2018. The 2022 European Respiratory Society-European Society of Cardiology guidelines suggest a cut-off for pulmonary vascular resistance of 2 Woods units.

  • ‡Pulmonary hypertension is clinically divided into five groups: pulmonary arterial hypertension (group 1), pulmonary hypertension caused by left heart disease (group 2), pulmonary hypertension caused by lung diseases, hypoxia, or both (group 3), chronic thromboembolic pulmonary hypertension and pulmonary hypertension caused by pulmonary artery obstructions (group 4), and pulmonary hypertension caused by unclear or multifactorial mechanisms (group 5).