The diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH) is difficult for numerous reasons and is related with a poor prognosis. In Taiwan, the incidence of CTEPH and its clinical features are unknown. This study aims at evaluating the prevalence, clinical characteristics, and management of CTEPH in a Taiwanese cohort.

Primary objective:

- To investigate the geodemographics of CTEPH in Taiwan

Secondary objectives:

• To characterize the demographics and clinical presentation of patients with CTEPH
• To describe the real-world management and treatment outcome of patients with CTEPH
• To identify the risk factors of CTEPH
• To assess the relationship between risk factors/patients' characteristics and clinical outcomes for CTEPH
• To evaluate the prognosis of CTEPH in Taiwan using survival assessment

Inclusion Criteria:

1. Right heart catheterization (RHC) results that are in line with both of the following haemodynamic levels:

   Mean pulmonary arterial pressure (mPAP) ≥ 25 mmHg at rest AND Pulmonary arterial wedge pressure (PAWP) ≤ 15 mmHg

2. Confirmation of CTEPH diagnosis by one of the following as recommended by standard guidelines:

   At least 1 (segmental) perfusion defect(s) in ventilation-perfusion (V/Q) / perfusion scan OR Pulmonary artery obstruction seen by multidetector computed tomography (MDCT) angiography or conventional pulmonary cineangiography.

3. Presence of pulmonary hypertension or evidence of pulmonary thromboembolism after at least 3 months of anticoagulation treatment.

Exclusion Criteria:

• not written informed consent
• not meet inclusion criteria

Patients with contrast CT image and cardiac echo data and confirmed/suspected as CTEPH can be included in the screening (initial registration). Those who have confirmed diagnosis of CTEPH in expert centers (IRB approved for patient enrollment) will be enrolled into the study.