Table 1.

Classification of pulmonary hypertension.

Group 1—Pulmonary Arterial Hypertension (PAH)

1.1 Idiopathic:

1.1.1 Non-responders at vasoreactivity testing

1.1.2 Acute responders at vasoreactivity testing

1.2 Heritable

1.3 Associated with drugs and toxins

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 disease

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

2.2 Valvular heart disease

2.3 Congenital/acquired cardiovascular conditions leading to post-capillary PH

Group 3—PH Associated with Lung Diseases and/or Hypoxia

3.1 Obstructive lung disease or emphysema

3.2 Restrictive lung disease

3.3 Lung disease with mixed restrictive/obstructive pattern

3.4 Hypoventilation syndromes

3.5 Hypoxia without lung disease (e.g., high altitude)

3.6 Developmental lung disorders

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

5.3 Metabolic disorders

5.4 Chronic renal failure with or without hemodialysis

5.5 Pulmonary tumor thrombotic microangiopathy

5.6 Fibrosing mediastinitis

PAH: pulmonary arterial hypertension; HIV: human immunodeficiency virus; PVOD: pulmonary veno-occlusive disease; PCH: pulmonary capillary hemangiomatosis; PH: pulmonary hypertension. European Society of Cardiology & European Respiratory Society, [5].