Lauren Brash et al. BTS 2018;3:176-186 Patients With or Without PDE5 Inhibitor Treatment Hemodynamic changes during infusion of (Pyr1)apelin-13 (solid squares) or matched saline placebo (open squares) in patients with pulmonary arterial hypertension who are (A) on treatment with PDE5 inhibitors or (B) not on treatment with PDE5 inhibitors. Data are reported as mean ± SEM. *p = 0.049, **p = 0.0127, *** p = 0.0042, §p = 0.0039, §§p = 0.0017, #p = 0.0011, ##p = 0.0003, 2-way analysis of variance with post hoc Bonferroni tests. Abbreviations as in Figure 1. Lauren Brash et al. BTS 2018;3:176-186 2018 The Authors