Figure 2.

A, Measurement of AaPO2 while breathing 100% oxygen according to the etiologic groups of patients (difference between groups was not significant by oneway analysis of variance). B, PaO₂ on room air according to the etiologic groups (difference between groups was significant by Kruskal Wallis analysis, with p < 0.05; two-by-two post-hoc analysis was significant between groups 3 and 5, and group 4 by Bonferroni's multiple comparison test, p < 0.05). Group 1, pulmonary arterial hypertension; group 3, pulmonary hypertension associated with pulmonary diseases; group 4, chronic thromboembolic pulmonary hypertension; group 5, miscellaneous.