Pulmonary hypertension (PH)

Learning objectives

Describe the definition, clinical classes and treatment of pulmonary hypertension
Manage patients with pulmonary hypertension

Pulmonary hypertension is defined as a mean pulmonary artery pressure (MPAP) >25 mmHg at rest or 30 mmHg on exercise
The cause of pulmonary hypertension is of critical importance as it defines subsequent treatment
Patients are classified into five clinical groups:
- Group 1: Pulmonary arterial hypertension (PAH). Idiopathic PAH, connective tissue disease-associated PAH, and congenital heart disease (mainly Eisenmenger syndrome) are the most common subgroups; others include aortopulmonary, HIV, and drug/toxin-induced PAH
- Group 2: PH associated with increased pulmonary capillary wedge pressure (post-capillary PH), due to left-sided heart disease
- Group 3: Lung disease and chronic hypoxia-related PH
- Group 4: Predominantly chronic thromboembolic PH (CTEPH)
- Group 5: PH caused by multisystemic disorders or multiple/unknown mechanisms, including sarcoidosis and hematological conditions
Adequate coupling of the right ventricle to the pulmonary circulation is essential for maintaining cardiac output in patients with PH

Pulmonary vasodilator therapy is predominantly indicated for the treatment of patients with Group 1 PH and Group 4 PH, although the treatment of choice for CTEPH is pulmonary endarterectomy
Management of PH in patients with Group 2 and 3 PH is focussed on the underlying heart or lung disease
Transplantation (usually bilateral lung) remains the ultimate treatment option in PAH when other treatments fail

RV, right ventricle; PVR, pulmonary vascular resistance; ICU, intensive care unit; HDU, high dependency unit.