Anticoagulation therapy for pulmonary embolism usually takes 3-6 months. However, many patients with pulmonary embolism do not simply have pulmonary tethering alone, but also have lower extremity deep vein thrombosis. In such patients, oral anticoagulant medication is generally recommended for at least 6-12 months. For patients with pulmonary embolism with lower extremity deep vein thrombosis, after taking oral anticoagulant drugs, they should go to the hospital for review at 3, 6 and 12 months, and according to the results of the review, decide whether to stop taking anticoagulant drugs and whether to continue taking other drugs to prevent the recurrence of thrombosis after stopping anticoagulant drugs.