Table 1.

Classification and characteristics of different types of pulmonary hypertension.

Type of Pulmonary Hypertension	Pathogenesis	Hemodynamic Characteristics	Specific Drug Therapy
Pulmonary arterial hypertension Idiopathic Heritable Drugs and toxins induced Associated with Connective tissue disease HIV infection Portal hypertension Congenital heart disease Schistosomiasis Pulmonary veno-occlusive disease and/or pulmonary capillary haemangiomatosis Persistent pulmonary hypertension of the newborn	Usually multifactorial including alterations in: Genetics Inflammation Immunity Cell metabolism Hemodynamics	PAPm ≥ 25 mmHg and PAWP ≤ 15 mmHg and PVR > 3 WU	Calcium channel blockers Endothelin receptor antagonists Phosphodiesterase type 5 inhibitors Guanylate cyclase stimulators Prostacyclin analogues Prostacyclin receptor agonists
Pulmonary hypertension due to left heart disease	Passive backward transmission of filling pressures from the left heart	PAPm ≥ 25 mmHg and PAWP > 15 mmHg	Global management of the underlying condition of the left heart
Pulmonary hypertension due to lung diseases and/or hypoxia	Alveolar hypoventilation, vascular remodeling, parenchymal destruction, and fibrosis	PAPm ≥ 25 mmHg	Treatment of the underlying lung disease, long-term oxygen therapy in hypoxemic patients
Chronic thromboembolic pulmonary hypertension	Obstructive pulmonary artery remodeling as a consequence of vessel thromboembolism	PAPm ≥ 25 mmHg and PAWP ≤ 15 mmHg	Pulmonary endarterectomy, balloon pulmonary angioplasty, targeted medical therapy
Pulmonary hypertension with unclear and/or multifactorial mechanisms	Mechanisms are multifactorial and usually poorly understood	PAPm ≥ 25 mmHg	Treatment is tailored for underlying diagnosis; treatment of pulmonary hypertension is secondary

PAPm—mean pulmonary artery pressure, PAWP—pulmonary artery wedge pressure, PVR—pulmonary vascular resistance, WU—Wood unit.