CTEPH is a disease that causes progressive pulmonary hypertension due to stenoses or occlusions in the pulmonary artery due to an organized thrombus. And this is a disease that results in right heart failure and death unless early diagnosis and appropriate treatment are performed. Pulmonary endarterectomy (PEA), which surgically removes the intimal thrombus, has been established as the treatment of choice for CTEPH. In the AHA/ACC guideline and ESC guideline, PEA for CTEPH is class IC (1). In 2014, a soluble guanylate cyclase stimulant (generic name: riociguat), which is one of the therapeutic agents for pulmonary hypertension, was approved for patients with CTEPH who are ineligible for PEA, and residual pulmonary hypertension after PEA (2). In addition, it has been reported that BPA, which is a catheter interventional treatment, is also effective to improve hemodynamics in inoperable patients with CTEPH (3, 4). However, some patients have residual symptoms such as dyspnea on exertion even after normalization in hemodynamics by BPA. A randomized control study should be done to confirm the necessary of continuation of riociguat for such patients.
Riociguat could improve the exercise capacity and residual symptoms in patients with chronic thromboembolic pulmonary hypertension (CTEPH) even after normalization of pulmonary arterial pressure by balloon pulmonary angioplasty (BPA). This randomized controlled trial study aimed to clarify whether the improvement of peak cardiac index (CI) during exercise maintains or not between the riociguat continued group and the riociguat discontinued group.