The International Balloon Pulmonary Angioplasty (BPA) Registry is a prospective, multi-center, long-term observational project. Scheduled to start data collection in Q4 2017, the registry will run for approximately four years with a follow-up time for each patient of at least two years. Its primary objective is to investigate the efficacy and safety of BPA intervention in patients with chronic thromboembolic pulmonary hypertension (CTEPH) not amenable to pulmonary endarterectomy (PEA).