Group 1: Pulmonary arterial hypertension
  • Idiopathic
  • Heritable: associated with specific gene mutations like BMPR2, ALK1, endoglin, etc
  • Drug- & toxin-induced
  • Associated with: connective tissue diseases, HIV infection, portal hypertension, congenital heart diseases, schistosomiasis & chronic hemolytic anemia
  • Persistent pulmonary hypertension of the newborn

Group 1': Pulmonary veno-occlusive disease and/or pulmonary capillary hemangiomatosis
Group 2: PH secondary to left heart disease
  • Systolic dysfunction
  • Diastolic dysfunction
  • Valvular disease
Group 3: PH secondary to lung diseases and/or hypoxia
  • Chronic obstructive pulmonary disease
  • Interstitial lung disease
  • Other diseases with a mixed restrictive & obstructive pattern
  • Sleep disordered breathing
  • Alveolar hypoventilation disorders
  • Chronic exposure to high altitude
  • Developmental abnormalities
Group 4: Chronic thromboembolic pulmonary hypertension
Group 5: PH due to multi-factorial/unclear mechanisms.
  • Hematologic: myeloproliferative disorders, splenectomy
  • Systemic: sarcoidosis, pulmonary Langerhans cell histiocytosis
  • Metabolic disorders: glycogen storage disorders, Gaucher disease, thyroid disorders
  • Others: tumoral obstruction, fibrosing mediastinitis, chronic renal failure on dialysis
Table 1: Updated clinical classification of pulmonary hypertension [4] (Dana Point, 2008).