TABLE 1

Updated classification of pulmonary hypertension (PH)

1 Pulmonary arterial hypertension
 1.1 Idiopathic
 1.2 Heritable
  1.2.1 BMPR2 mutation
  1.2.2 ALK1, ENG, SMAD9, CAV1 and KCNK3 mutation
  1.2.3 Unknown
 1.3 Drug and toxin induced
 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 diseases
  1.4.5 Schistosomiasis
1′ Pulmonary veno-occlusive disease and/or pulmonary capillary haemangiomatosis
 1′.1 Idiopathic
 1′.2 Heritable
  1′.2.1 EIF2AK4 mutation
  1′.2.2 Other mutations
 1′.3 Drug, toxin and radiation induced
 1′.4 Associated with
  1′.4.1 Connective tissue disease
  1′.4.2 HIV infection
1″ Persistent PH of the newborn
2 PH due to left heart disease
 2.1 Left ventricular systolic dysfunction
 2.2 Left ventricular diastolic dysfunction
 2.3 Valvular disease
 2.4 Congenital/acquired left heart inflow/outflow tract obstruction and congenital cardiomyopathies
3 PH due to lung diseases and/or hypoxia
 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
4 Chronic thromboembolic PH
5 PH with unclear multifactorial mechanisms
 5.1 Haematological disorders: chronic haemolytic anaemia, myeloproliferative disorders and splenectomy
 5.2 Systemic disorders: sarcoidosis, pulmonary histiocytosis and lymphangioleiomyomatosis
 5.3 Metabolic disorders: glycogen storage disease, Gaucher disease and thyroid disorders
 5.4 Others: tumoural obstruction, fibrosing mediastinitis, chronic renal failure and segmental PH
  • BMPR: bone morphogenic protein receptor type II; ALK1: activin receptor-like kinase 1; ENG: endoglin; CAV1: caveolin-1; KCNK3: potassium channel, two pore domain subfamily K, member 3; EIF2AK4: eukaryotic translation initiation factor 2α kinase 4. Reproduced and modified from [1].