PURPOSE: WHO Functional Class (WHO FC) is used as a means of classifying disease severity in pulmonary arterial hypertension (PAH). However, comparisons of objective measures of disease severity among functional classes, and correlations between functional and hemodynamic parameters within each specific class, have not been fully investigated in the context of multicenter studies. We compared the baseline data of idiopathic PAH patients enrolled in BREATHE-1 and 351 studies (enrolling WHO FC III subjects) with those of patients enrolled in the EARLY study, an ongoing prospective, placebo-controlled trial with bosentan designed specifically to study WHO FC II PAH patients.
METHODS: Baseline functional and hemodynamic data from 65 patients with idiopathic PAH from EARLY and 162 idiopathic PAH patients from the BREATHE-1 and 351 studies all naïve to targeted PAH therapies (e.g., prostanoids, phosphodiesterase V inhibitors), were compared. Correlation between the six-minute walk distance (6MWD) and hemodynamics were also performed.
RESULTS: Mean ± SD data of 6MWD and hemodynamics of each WHO FC group and correlation coefficients between 6MWD and hemodynamics within each WHO FC groups are reported.
CONCLUSION: Baseline 6MWD and hemodynamics of WHO FC II and III patients differ and are more compromised in the latter. There is a poor correlation between rest hemodynamics and exercise capacity in both WHO FC II and III.
CLINICAL IMPLICATIONS: Since FC, 6MWD and hemodynamics have prognostic importance, assessment of severity should incorporate all these measures.
DISCLOSURE: Nazzareno Galie, Employee Andjela Kusic-Pajic and Eleonora Chiossi are employees of Actelion Pharmaceuticals Ltd, the manufacturer of bosentan.; Consultant fee, speaker bureau, advisory committee, etc. Nazzareno Galie, Lewis Rubin, Marius Hoeper and Gerald Simonneau have been remunerated consultants for Actelion Pharmaceuticals Ltd, the manufacturers of bosentan; Product/procedure/technique that is considered research and is NOT yet approved for any purpose, Bosentan is not approved for use in WHO Functional Class II patients.