Table 1.

Updated classification of pulmonary hypertension (PH).

Group 1-Pulmonary arterial hypertension (PAH)

1.1 Idiopathic PAH

1.2 Heritable PAH (e.g., BMPR2, ALK1 and ENG mutation)

1.3 Drug- and toxin-induced pah

1.4 PAH-associated with (1.4.1 Connective tissue disease; 1.4.2 HIV infection; 1.4.3 Portal hypertension; 1.4.4 Congenital heart diseases; 1.4.5 Schistosomiasis)

1.5 PAH long-term responders to calcium channel blockers

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

1.7 Persistent PH of the newborn syndrome

Group 2-PH due to left heart disease

2.1 Left ventricular systolic dysfunction

2.2 Left ventricular diastolic dysfunction

2.3 Valvular heart disease

2.4 Congenital/acquired left heart inflow/outflow tract obstruction and congenital cardiomyopathies

Group3- PH due to lung diseases

3.1 Chronic obstructive pulmonary disease

3.2 Interstitial lung disease

3.3 Other pulmonary diseases with mixed restrictive and obstructive pattern

3.4 Sleep disordered breathing

3.5 Alveolar hypoventilation disorders

3.6 Chronic exposure to high altitude

3.7 Developmental lung diseases

Group 4- PH due to chronic thromboembolism

Group 5- PH due to other causes

5.1 Haematological disorders

5.2 Systemic and metabolic disorders

5.3 Others

5.4 Complex congenital heart disease

BMPR2: bone morphogenic protein receptor type II; ALK1: activin receptor-like kinase 1; ENG: endoglin (referenced by Ref. [1]).