Kaplan-Meier survival estimates based on the percentage change in the 6-min walk distance (6MWD) ± 10 percentage points for all patients with a baseline 6MWD and follow-up 6MWD within 1 year. Reprinted without changes from Elsevier, Farber et al., Predicting outcomes in pulmonary arterial hypertension based on the 6-min walk distance, Mar 1, 2015, volume 34, issue 3, page 7, under the Creative Commons open access license agreement (CC BY-NC-ND 4.0) [25]