Frailty, Physical Capacity and Lung Function in Postoperative Pulmonary Endarterectomy Patients

This study is measuring how frailty, physical fitness, and lung function change before and after surgery to remove blood clots from the lungs (pulmonary endarterectomy), to better understand recovery patterns. **You may be eligible if...** - You are 18 or older (any gender) - You are scheduled for a planned pulmonary endarterectomy (a surgery to remove chronic blood clots from the lungs) - You have no cognitive or physical impairments that would prevent you from doing functional tests before surgery **You may NOT be eligible if...** - This is a repeat operation for any reason - You develop cognitive or physical impairments after surgery that prevent functional testing Talk to your doctor to see if this trial is right for you.