I. Systemic thrombolytic therapy for acute pulmonary embolism (PE) 1. In patients with acute PE combined with hypotension (e.g., systolic blood pressure <90 mmHg), systemic thrombolytic therapy is recommended if there is no high risk of bleeding (grade 2B). 2. For most patients with acute PE without combined hypotension, systemic thrombolysis is not recommended (class 1C). 3. Systemic thrombolysis is recommended for certain patients with acute PE without initial hypotension and low risk of bleeding who are at high risk of progressive hypotension after initiation of anticoagulation therapy (class 2C). Note: Patients with PE without hypotension who have severe symptoms or significant cardiopulmonary impairment need to be monitored closely for deterioration. The presence of hypotension indicates an indication for thrombolytic therapy. Deterioration of cardiopulmonary function (e.g., symptoms, vital signs, tissue perfusion, gas exchange, cardiac markers) without progression to hypotension requires a risk-benefit assessment, and thrombolytic therapy may be performed if it is assessed to be superior to anticoagulation alone. This recommendation is more in line with clinical practice and gives clinicians more room for individualized treatment. Catheter intervention for acute pulmonary embolism 1. In patients with acute PE who choose thrombolytic drug therapy, systemic thrombolysis via peripheral transvenous is recommended over catheter interventional thrombolytic therapy (CDT) (Class 2C). Note: Patients at high risk of bleeding from systemic thrombolysis who have access to specialists and resources to perform CDT are more likely to choose CDT over systemic thrombolysis. The importance of a clinical team with experience in interventional therapy is emphasized here. 2. In acute PE patients with combined hypotension, if there is a high risk of bleeding, failure of systemic thrombolytic therapy, or shock that may lead to death before the onset of systemic thrombolytic therapy (e.g., within hours), catheter intervention-assisted thrombus removal is recommended when appropriate specialists and resources are available (Class 2C). Note: Catheter-assisted thrombectomy refers to mechanical removal with or without catheter-mediated thrombolysis. III. Pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension (CTEPH) Pulmonary thromboendarterectomy is recommended for certain patients with CTEPH if confirmed by an experienced pulmonary thromboendarterectomy team (Class 2C). NOTE: Patients with CTEPH should be evaluated by a team of experts in the treatment of pulmonary hypertension. Pulmonary thromboendarterectomy is often life-saving and life-changing. Patients with CTEPH who are unable to undergo pulmonary thromboendarterectomy may still benefit from other mechanical or pharmacologic treatments aimed at reducing pulmonary artery pressure. Thrombolytic therapy in patients with acute upper extremity DVT (UEDVT) 1. In patients with acute upper extremity DVT involving axillary veins or more proximal veins, anticoagulation alone is recommended over thrombolytic therapy (Class 2C). Note: Patients who are more likely to choose thrombolysis over anticoagulation alone: (1) are likely to benefit from thrombolysis; (2) can apply CDT; (3) are more concerned about preventing PTS; (4) do not care about the complexity, cost, and bleeding risk of thrombolysis initiation. 2. Patients with acute upper extremity DVT treated with thrombolysis are recommended to apply the same intensity and duration of anticoagulation therapy as similar patients who did not receive thrombolysis (class 1B). V. Anticoagulation for recurrent VTE 1. Patients with recurrent VTE during treatment with vitamin K antagonists (VKA) (INR in therapeutic range) or with dabigatran, rivaroxaban, apixaban or edoxaban (good compliance) are recommended to switch to LMWH therapy at least temporarily (level 2C). NOTE: VTE recurrence is rare in therapeutic doses of anticoagulation, and recurrence despite standardized therapy should be evaluated by (1) reassessing whether it is indeed a VTE recurrence, (2) assessing compliance with anticoagulation therapy, and (3) considering the possible presence of malignancy. Temporary switch to LMWH therapy is usually for at least 1 month. This recommendation is more in line with the clinical reality. 2. Patients receiving long-term LMWH anticoagulation therapy (good compliance) who develop VTE recurrence are recommended to increase the dose of LMWH by about 1/4 to 1/3. NOTE: VTE recurrence is rare in therapeutic doses of anticoagulation and should be evaluated by (1) reassessing whether it is indeed a VTE recurrence, (2) assessing compliance with anticoagulation therapy, and (3) considering the possible presence of malignancy. Recurrence despite therapeutic doses of low-molecular heparin anticoagulation should be considered for LMWH dosing.