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. Author manuscript; available in PMC: 2019 Mar 1.
Published in final edited form as: Clin Pulm Med. 2018 Mar;25(2):52–60. doi: 10.1097/CPM.0000000000000252

Table 1. World Health Organization Classification of Pulmonary Hypertension11.

Pulmonary hypertension is defined by the World Health Organization as a mean pulmonary artery pressure ≥ 25 as measured by right heart catheterization. The diagnosis of pulmonary arterial hypertension (Group 1) also requires measured pulmonary vascular resistance of >3 Wood units. Items in bold represent etiologies which have been implicated in SAPH.

  • 1
    Pulmonary Arterial Hypertension (PAH)
    • 1.1
      Idiopathic PAH
    • 1.2
      Heritable PAH
    • 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 hemangiomatosis

  • 1”

    Persistent pulmonary hypertension of the newborn

  • 2
    Pulmonary hypertension 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
    Pulmonary hypertension 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 pulmonary hypertension

  • 5
    Pulmonary hypertension with unclear multifactorial mechanisms
    • 5.1
      Hematologic disorders: chronic hemolytic anemia, myeloproliferative disorders, splenectomy
    • 5.2
      Systemic disorders: sarcoidosis, pulmonary histiocytosis, lymphangioleiomyomatosis
    • 5.3
      Metabolic disorders: glycogen storage disease, Gaucher disease, thyroid disorders
    • 5.4
      Others: tumoral obstruction, fibrosing mediastinitis, chronic renal failure, segmental pulmonary hypertension