BPA in CTEPD Without PH

Inclusion Criteria: * acute pulmonary embolism at least 3 months prior to inclusion and adequately treated * persistent functional limitations: (New York Heart Association (NYHA) class ≥2) * persistent radiological perfusion defects: ≥ 3 segmental perfusion defects * CPET result with: 1. at least 2 of the following criteria: * peak VO2 \< 80%; * peak O2 pulse \< 80% of predicted; * V'E/V'CO2 @ nadir \> 34; * Vd/Vt increasing until peak exercise or peak Vd/Vt \> 0;4; * gradual drop of SpO2 of ≥ 3%; 2. these exercise findings cannot be explained otherwise 2. patients completed a pulmonary rehabilitation program of at least 8 weeks no longer than 2 months before randomization. 3\. exercise tests were performed after the pulmonary rehabilitation program 4. age 18-80 years 5. Clinical Frailty Scale (CFS) score \< 5 (CFS is a 9-point scale that summarizes the overall level of fitness or frailty of an older adult) 6. written informed consent 7. prior treatment or restart therapeutic dose of anticoagulation treatment before randomization Exclusion Criteria: 1. history of balloon pulmonalis angiography (BPA) or pulmonary endarterectomy 2. residual thrombi that are not eligible for BPA 3. major acute or chronic cardiopulmonary comorbidities with an expected impact on survival, exercise capacity and/or gas exchange, e.g. significant coronary heart disease, diastolic/systolic heart failure, pulmonary hypertension (mPAP \> 25 mmHg), severe chronic obstructive pulmonary disease (COPD) GOLD class ≥3, interstitial lung disease (ILD), disabling neuromuscular disease, malignancy 4. inability to undergo exercise tests 5. contrast allergy 6. creatinine clearance \< 30ml/min 7. pregnancy or breastfeeding