TABLE 1.

2022 classification of pulmonary hypertension [4]

1 PAH

1.1 Idiopathic PAH

1.1.1 Non-responders at vasoreactivity testing

1.1.2 Acute responders at vasoreactivity testing

1.2 Heritable

1.3 Associated with drugs and toxins

1.4 Associated with:

1.4.1 Connective tissue disease

1.4.2 HIV infection

1.4.3 Portal hypertension

1.4.4 Congenital heart disease

1.4.5 Schistosomiasis

1.5 PAH with features of venous/capillary (PVOD/PCH) involvement

1.6 Persistent pulmonary hypertension of the newborn syndrome

2 Pulmonary hypertension associated with left heart disease

2.1 Pulmonary hypertension due to heart failure

2.1.1 With preserved ejection fraction

2.1.2 With reduced or mildly reduced ejection fraction

2.2 Valvular heart disease

2.3 Congenital/acquired cardiovascular conditions leading to post-capillary pulmonary hypertension

3 Pulmonary hypertension associated with lung diseases and/or hypoxia

3.1 Obstructive lung disease or emphysema

3.2 Restrictive lung disease

3.3 Lung disease with mixed restrictive/obstructive pattern

3.4 Hypoventilation syndromes

3.5 Hypoxia without lung disease (e.g. high altitude)

3.6 Developmental lung disorders

4 Pulmonary hypertension associated with pulmonary artery obstructions

4.1 Chronic thromboembolic pulmonary hypertension

4.2 Other pulmonary artery obstructions

5 Pulmonary hypertension with unclear and/or multifactorial mechanisms

5.1 Haematological disorders

5.2 Systemic disorders

5.3 Metabolic disorders

5.4 Chronic renal failure with or without haemodialysis

5.5 Pulmonary tumour thrombotic microangiopathy

5.6 Fibrosing mediastinitis

PAH: pulmonary arterial hypertension; PVOD: pulmonary veno-occlusive disease; PCH: pulmonary capillary haemangiomatosis.