Fig. 2From: Exhaled nitric oxide is not a biomarker for idiopathic pulmonary arterial hypertension or for treatment efficacySix minute walk distance (6MWD) changes in the three WHO functional classes before and after treatment. The effects of treatment on the 6MWD in class I (n = 8 subjects), II (n = 17 subjects) and III (n = 11 subjects). Data are presented as mean ± semBack to article page