Haemodynamic effects of riociguat in inoperable/recurrent chronic thromboembolic pulmonary hypertension

Objective We compared the haemodynamic effects of riociguat in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH) or persistent/recurrent CTEPH after pulmonary endarterectomy in the Chronic Thromboembolic Pulmonary Hypertension Soluble Guanylate CyclaseStimulator Trial 1 study. Methods Patients with inoperable or persistent/recurrent CTEPH (n= 261; mean +/- SD age 59 +/- 14 years; 66% women) were randomised to riociguat (up to 2.5 mg three times daily) or placebo. Haemodynamic parameters were assessed at baseline and week 16. Results Riociguat decreased pulmonary vascular resistance (PVR) in inoperable (n= 189; least-squares mean difference: -285 dyn s/cm(5) (95% CI -357 to -213); p< 0.0001) and persistent/recurrent (n= 72; -131 dyn s/cm(5) (95% CI -214 to -48); p= 0.0025) patients. Cardiac index improved in inoperable patients by a least-squares mean difference of + 0.6 L/min/m(2) (95% CI 0.4 to 0.7; p< 0.0001), while in persistent/recurrent patients the change was + 0.2 L/min/m(2) (95% CI -0.1 to 0.5; p= 0.17). Mean pulmonary artery pressure decreased in inoperable and persistent/recurrent patients(-4.7 mm Hg (95% CI -6.9 to -2.6; p< 0.0001 and -4.8 mm Hg (-8.2 to -1.5; p= 0.0055), respectively). For all patients, changes in 6 min walk distance correlated with changes in PVR (r=-0.29 (95% CI -0.41 to -0.17); p< 0.0001) and cardiac index (r= 0.23 (95% CI 0.10 to 0.35); p= 0.0004). Conclusions Riociguat improved haemodynamics in patients with inoperable CTEPH or persistent/recurrent CTEPH.