SaExten Vena Cava Filter System in Prevention of Pulmonary Embolism

Inclusion Criteria: 1. Age ≥18 years old and life expectancy ≥ 12 months; 2. The diameter of inferior vena cava is between 18.0mm and 26.0mm; 3. Patients with acute (≤14 days of onset) proximal (inferior lumen, iliac, femoral, popliteal vein) deep vein thrombosis (DVT), or at risk of pulmonary embolism (PE) caused by thrombus detoxification, with or without symptoms of pulmonary embolism; 4. People at risk of pulmonary embolism (PE) meet at least one of the following conditions: * Patients with acute DVT who plan to undergo catheter-directed thrombolysis (CDT), percutaneous mechanical thrombectomy (PMT) or surgical thrombectomy; * Patients who have failed anticoagulant therapy, have recurrent PE and/or DVT, and have contraindications to anticoagulant therapy or are at serious risk of bleeding; * Floating thrombus in iliac, femoral vein or inferior vena cava; * Patients with high risk factors for acute DVT and PE who underwent abdominal, pelvic or lower limb surgery; * Patients with DVT who have already developed a large area of PE and are at risk of developing PE again; * DVT accompanied by serious heart and lung disease, pulmonary hypertension; * Severe injuries (such as hip fracture, etc.), accompanied by vascular endothelial injury, accompanied by blood hypercoagulability and anticoagulant therapy contraindications; 5. Those who can understand the purpose of the trial, cooperate with the follow-up, and sign the informed consent voluntarily. Exclusion Criteria: 1. Patients with severe stenosis or deformity of the inferior vena cava or severe spinal deformity; 2. Patients with uncontrolled infectious diseases, purulent embolism or fat embolism; 3. Previous vena cava filter implantation history; 4. Thrombosis in the venous access required for the filter implantation; 5. Patients with severe liver and renal dysfunction (ALT\>3 times the upper limit of normal; Creatinine\>225umol/L); 6. Patients with known uncorrectable bleeding or severe coagulation disease; 7. Patients who are allergic to contrast agents, nickel and have contraindication to X-ray; 8. With disease causing difficulties in treatment and evaluation (such as septicemia, bacteremia, toxemia, severe metabolic disease, cancer metastasis, mental illness, etc.); 9. Malignant tumor patients; 10. Pregnant and lactating women, or those who is planning parenthood; 11. Participated in clinical trials of other drugs or medical devices before inclusion and haven't reach the end point time limit; 12. Persons considered by the investigator to be unsuitable for participation in this clinical trial.