Multicentre randomised controlled trial of balloon pulmonary angioplasty and riociguat in patients with chronic thromboembolic pulmonary hypertension: protocol for the MR BPA study

INTRODUCTION: Management of inoperable chronic thromboembolic pulmonary hypertension (CTEPH) remains a clinical challenge. Currently, medical treatment involving pulmonary vasodilators (such as soluble guanylate-cyclase stimulators) is recommended, primarily for ameliorating symptoms. More recently, balloon pulmonary angioplasty (BPA) has been developed as alternative treatment for inoperable CTEPH. This study aimed to compare the efficacy and safety of BPA and riociguat (a soluble guanylate-cyclase stimulator) as treatments for inoperable CTEPH. METHODS AND ANALYSIS: This study is a multicentre randomised controlled trial. Subjects with inoperable CTEPH were randomised (1:1) into either a BPA or riociguat group, and observed for 12 months after initiation of treatment. The primary endpoint will be the change in mean pulmonary arterial pressure from baseline to 12 months after initiation of treatment. For primary analysis, we will estimate the least square means difference and 95% CI for the change of pulmonary arterial pressure between the groups at 12 months using the analysis of covariance adjusted for allocation factors. ETHICS AND DISSEMINATION: This study and its protocols were approved by the institutional review board of Keio University School of Medicine and each participating institution. Written informed consent was obtained from all participants. Results will be disseminated at medical conferences and in journal publications. TRIAL REGISTRATION NUMBER: University Hospital Medical Information Network Clinical Trial Registry (UMIN000019549); Pre-results.