Functional evaluation of patients with chronic pulmonary hypertension

The importance of studying the pathophysiological bases and clinical correlates of exercise limitation in patients with pulmonary arterial hypertension (PAH) is well established. Two modes of exercise testing, the 6-min walk test (6MWT) and the cardiopulmonary exercise test (CPET), are currently proposed for diagnostic, therapeutic and prognostic finalities. The 6MWT is inexpensive, feasible and is thought to better reproduce daily life activities and to reliably detect therapeutic benefits. CPET requires the patient's maximal effort and does not provide a reliable quality of life measure. It is, however, highly reproducible and provides remarkable insights into the pathophysiological mechanisms that lead to exercise intolerance. Due to the limited experience accumulated, CPET is not actually advised for the routine assessment and for the overall clinical decision making of PAH patients. In this review we critically address the knowledge currently acquired on these techniques.