Management of severe pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a severe, progressive condition of the small pulmonary vessels that leads to increased pulmonary vascular resistance, right ventricular failure and death. Patients in World Health Organization functional class (WHO FC) IV are the most severely affected in terms of disease severity, symptomatic impairment, exercise capacity and haemodynamics, with a very poor prognosis and low survival rate. Recent developments in PAH-specific therapies have conferred significant prognostic improvements upon PAH patients, especially when coupled with management strategies such as goal-oriented therapy and combination treatment. Despite these important developments, the outlook for WHO FC IV PAH patients remains poor. This article examines the recommendations for WHO FC IV patients that appear in current PAH treatment guidelines and the research underpinning this guidance, and discusses possible future directions for treatment of this severely unwell patient population.