Version July 2025
| Group 1 – PAH |
| 1.1 Idiopathic |
| 1.1.1 Long-term responders to CCBs |
| 1.2 Heritable* |
| 1.3 Associated with drugs and toxins* |
| 1.4 Associated with: |
| 1.4.1 CTD |
| 1.4.2 HIV infection |
| 1.4.3 Portal hypertension |
| 1.4.4 CHD |
| 1.4.5 Schistosomiasis |
| 1.5 PAH with features of venous/capillary (PVOD/PCH) involvement |
| 1.6 Persistent PH of the newborn |
| Group 2 – PH associated with left heart disease |
| 2.1 Heart failure: |
| 2.1.1 With preserved ejection fraction |
| 2.1.2 With reduced or mildly reduced ejection fraction |
| 2.1.3 Cardiomyopathies with specific etiologies¶ |
| 2.2 Valvular heart disease: |
| 2.2.1 Aortic valve disease |
| 2.2.2 Mitral valve disease |
| 2.2.3 Mixed valvular disease |
| 2.3 Congenital/acquired cardiovascular conditions leading to postcapillary PH |
| Group 3 – PH associated with lung diseases and/or hypoxia |
| 3.1 COPD and/or emphysema |
| 3.2 Interstitial lung disease |
| 3.3 Combined pulmonary fibrosis and emphysema |
| 3.4 Other parenchymal lung diseasesΔ |
| 3.5 Nonparenchymal restrictive diseases: |
| 3.5.1 Hypoventilation syndromes |
| 3.5.2 Pneumonectomy |
| 3.6 Hypoxia without lung disease (eg, high altitude) |
| 3.7 Developmental lung diseases |
| Group 4 – PH associated with pulmonary artery obstructions |
| 4.1 Chronic thromboembolic PH |
| 4.2 Other pulmonary artery obstructions◊ |
| Group 5 – PH with unclear and/or multifactorial mechanisms |
| 5.1 Hematological disorders§ |
| 5.2 Systemic disorders: sarcoidosis, pulmonary Langerhans cell histiocytosis, and neurofibromatosis type 1 |
| 5.3 Metabolic disorders¥ |
| 5.4 Chronic kidney failure with or without hemodialysis |
| 5.5 Pulmonary tumour thrombotic microangiopathy |
| 5.6 Fibrosing mediastinitis |
| 5.7 Complex CHD |
CCBs: calcium channel blockers; CHD: congenital heart disease; COPD: chronic obstructive pulmonary disease; CTD: connective tissue disease; HIV: human immunodeficiency virus; PAH: pulmonary arterial hypertension; PCH: pulmonary capillary hemangiomatosis; PVOD: pulmonary veno-occlusive disease.
* Patients with heritable PAH or PAH associated with drugs and toxins might be long-term responders to CCBs.
¶ Hypertrophic, amyloid, Fabry disease, and Chagas disease.
Δ Parenchymal lung diseases not included in group 5.
◊ Other causes of pulmonary artery obstructions include sarcomas (high- or intermediate-grade or angiosarcoma), other malignant tumors (eg, renal carcinoma, uterine carcinoma, germ-cell tumors of the testis), nonmalignant tumors (eg, uterine leiomyoma), arteritis without CTD, congenital pulmonary arterial stenoses and hydatidosis.
§ Including inherited and acquired chronic hemolytic anemia and chronic myeloproliferative disorders.
¥ Including glycogen storage diseases and Gaucher disease.
