Riociguat and balloon pulmonary angioplasty (BPA) are established standard-of-care interventions for inoperable chronic thromboembolic pulmonary hypertension (CTEPH) with comparable evidence levels. However, the optimal combined treatment strategy remains unclear. Specifically, there is no consensus on whether riociguat should be continued long-term after achieving hemodynamic stability with BPA. Additionally, the long-term effects of riociguat discontinuation on right ventricular (RV) structure and function remain poorly characterized, particularly due to the lack of comprehensive noninvasive evaluations integrating cardiac magnetic resonance (CMR) and echocardiography. This prospective study aims to determine the hemodynamic impact of riociguat discontinuation in inoperable CTEPH patients who have achieved BPA treatment endpoints using right heart catheterization (RHC). Evaluate RV remodeling and functional changes after riociguat cessation through multimodal noninvasive imaging (CMR, echocardiography). Assess safety outcomes and identify potential rebound pulmonary hypertension or decompensated RV dysfunction associated with riociguat withdrawal.

Inclusion Criteria:

• Age ≥18 years old
• CTEPH was diagnosed and one of the following three factors was met: Pulmonary endarterectomy was technically impossible; Pulmonary endarterectomy is technically feasible, but the risk-benefit ratio is poor; Residual/recurrent pulmonary hypertension after pulmonary endarterectomy
• Subjects had been treated with BPA and had received a stable dose of riociguat for ≥12 weeks
• mPAP < 30mmHg
• Male subjects and female subjects of reproductive age are required to use effective contraception for at least 28 days after signing the informed consent form. Male subjects are not allowed to donate sperm and female subjects are not allowed to breastfeed.
• Subjects voluntarily sign written informed consent

Exclusion Criteria:

• Severe hepatic and renal insufficiency (Child-Pugh Grade C/creatinine clearance < 30ml/min·1.73m²)
• The presence of severe infectious disease or severe bleeding tendency
• Combined with pulmonary hypertension of other types than CTEPH
• Other pulmonary hypertension targeting drugs are being used
• The expected survival time with cancer or other diseases is less than 6 months
• Pregnancy, lactation
• Subjects are currently participating in an interventional clinical trial
• In the investigator's judgment, a subject's medical abnormality, physical condition, or medical history may affect his or her ability to participate in or complete the study