Early Detection of CTEPH in Patients After APE

This study aims to detect a serious complication called CTEPH (chronic thromboembolic pulmonary hypertension) — a type of persistent high blood pressure in the lungs — in patients who have recently had a pulmonary embolism (blood clot in the lungs). **You may be eligible if...** - You are over 18 years old - You had a pulmonary embolism (blood clot in the lungs) in the past 3 to 12 months - You are still on blood thinners - You have new or worsening shortness of breath since your embolism **You may NOT be eligible if...** - You have had CTEPH or pulmonary hypertension diagnosed before - You have active cancer being treated with chemotherapy - You have serious heart disease or other conditions that explain your breathing symptoms - You are pregnant Talk to your doctor to see if this trial is right for you.