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 Cyclase–Stimulator 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. TRIAL REGISTRATION NUMBER: NCT00855465.