The role of cardiopulmonary exercise tests in pulmonary arterial hypertension.

Despite recent advances in the therapeutic management of patients affected by pulmonary arterial hypertension (PAH), survival remains poor. Prompt identification of the disease, especially in subjects at increased risk of developing PAH, and prognostic stratification of patients are a necessary target of clinical practice but remain challenging. Cardiopulmonary exercise test (CPET) parameters, particularly peak oxygen uptake, end-tidal carbon dioxide tension and the minute ventilation/carbon dioxide production relationship, emerged as new prognostic tools for PAH patients. Moreover, CPET provides a comprehensive pathophysiological evaluation of patients' exercise limitation and dyspnoea, which are the main and early symptoms of the disease. This review focuses on the role of CPET in the management of PAH patients, reporting guideline recommendations for CPET and discussing the pathophysiology of exercise limitation and the most recent use of CPET in the diagnosis, prognosis and therapeutic targeting of PAH.