TABLE 1.

Classification of PH (Adopted from Simonneau et al¹)

1. PAH: mPAP >20 mmHg, PCWP <15 mmHg, PVR >3.0 wood units

1.1 Idiopathic PAH

1.2 Heritable PAH

1.3 Drug- and toxin-induced PAH

1.4 PAH 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 long-term responders to calcium channel blockers

1.6 PAH with overt features of venous/capillaries (PVOD/PCH) involvement

1.7 Persistent PH of the newborn syndrome

2. PH due to left heart disease: mPAP >20 mmHg, PCWP >15 mmHg

2.1 PH due to heart failure with preserved LVEF

2.2 PH due to heart failure with reduced LVEF

2.3 Valvular heart disease

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

3. PH due to lung diseases and/or hypoxia: mPAP >20 mmHg

3.1 Obstructive lung disease

3.2 Restrictive lung disease

3.3 Other lung disease with mixed restrictive/obstructive pattern

3.4 Hypoxia without lung disease

3.5 Developmental lung disorders

4. PH due to pulmonary artery obstructions: mPAP >20 mmHg

4.1 Chronic thromboembolic PH

4.2 Other pulmonary artery obstructions

5. PH with unclear and/or multifactorial mechanisms: mPAP >20 mmHg

5.1 Hematological disorders

5.2 Systemic and metabolic disorders

5.3 Others

5.4 Complex congenital heart disease

Abbreviations: LVEF, Left ventricular ejection fraction; mPAP, mean pulmonary arterial pressure; PAH, pulmonary arterial hypertension; PCH, pulmonary capillary hemangiomatosis; PCWP, pulmonary capillary wedge pressure; PH, pulmonary hypertension; PVOD, pulmonary veno-occlusive disease; PVR, pulmonary vascular resistance.