Arterial Wave Energy Flux and Multidimensional Recovery in Patients With Chronic Thromboembolic Pulmonary Hypertension Undergoing Balloon Pulmonary Angioplasty

The goal of this observational study is to learn if advanced heart pressure wave analysis (called WIA and REPA) can help track and predict clinical improvement in adults (aged 18-85) with Chronic Thromboembolic Pulmonary Hypertension (CTEPH) who are undergoing Balloon Pulmonary Angioplasty (BPA). The main questions it aims to answer are: Do changes in these advanced heart pressure wave patterns relate to improvements in a patient's walking distance, heart function, and overall quality of life after BPA treatment? Are these new measurements more effective than standard heart pressure tests at showing how much a patient has truly improved? Participants will: Undergo standard Balloon Pulmonary Angioplasty (BPA) sessions as part of their regular medical care for CTEPH. Have their heart pressure waves recorded through a catheter during the routine BPA procedure (this does not require any extra surgical steps). Complete walking tests (6-minute walk test), blood tests, and heart ultrasounds (echocardiography) before starting the treatment and after it is completed. Fill out short surveys regarding their daily physical activity and quality of life.