Effect of riociguat on pulmonary arterial compliance (PAC) in patients with PAH in PATENT-1

Background: PAC is determined by pulmonary artery stiffness and is a physiologic descriptor of right ventricular afterload. PAC was shown to predict survival in a small study of PAH pts, but changes in PAC in response to therapy have never been reported in PAH. Aims: This post-hoc analysis assessed the effect of the sGC stimulator riociguat on PAC in PAH pts in PATENT-1. Methods: Pts (n=443) received riociguat up to 2.5 mg tid (2.5 mg–max), riociguat up to 1.5 mg tid (exploratory arm), or placebo for 12 wks. PAC and systemic arterial compliance (SAC) were defined as stroke volume/(systolic blood pressure–diastolic blood pressure) in the pulmonary and systemic circulation, respectively. Results: PAC values were abnormally low at baseline (Table 1) and correlated significantly with NT-proBNP (r=–0.30; p Conclusions: In PATENT-1, riociguat significantly improved pulmonary artery stiffness in pts with PAH. Improvements in PAC correlated with improvements in pulmonary hemodynamics.