A Multi-center, Randomized Controlled Trial to evaluate the safety and efficacy of Fitaya Vena Cava Filter manufactured by Lifetech Scientific (Shenzhen) Co., LTD. for deep vein thrombosis.

The trial was mainly for patients with high-risk deep vein thrombosis, and all subjects who passed the screening and signed the informed consent will be enrolled and be randomly divided into the experimental group and the control group according to the proportion of 1:1. For patients who will be allocated to the experimental group will be implanted with Fitaya Vena Cava Filters System, and for patients who will be allocated to the control group will be implanted with Aegisy Vena Cava Filters. Between 0 and 60 days, after the filter was implanted, the investigator will decide whether to withdraw the vena cava filter based on the subject's condition. If successfully withdraw the vena cava filter, the subject will be followed up for 1 month, if the withdraw is unsuccessful, the subject will be followed up for 180 days. This clinical trial is conducted in qualified clinical trial institutions with a planned duration of 16-24 months. Upon completion of the clinical trial report, it will be submitted together with other materials for the application for listing registration in the China Food and Drug Administration (CFDA).

Inclusion Criteria:

1. Older or equal to 18 years of age, regardless of sex.

2. Patients are able to understand the purpose of the trial, voluntarily participated in and signed informed consent, and are willing to complete the follow-up as required by the program.

3. Patients diagnosed with inferior deep vein thrombosis (inferior vena cava, Iliac, femoral or popliteal DVT) or pulmonary embolism (PE), and concomitant with one or more of the following situation:

   1. with the existence of contraindications for anticoagulation therapy.
   2. complications such as bleeding occurred during anticoagulation therapy.
   3. pulmonary embolism still recurred after adequate anticoagulation therapy.
   4. All reasons cannot achieve sufficient anticoagulant.
   5. PE coexist with inferior DVT.
   6. Free thrombosis or large amounts of thrombosis are found in the iliac, femoral, popliteal or inferior vena cava.
   7. Patients with acute risk factors of DVT and PE needed to undergo abdominal, pelvic or lower limb surgery simultaneously.
   8. The patients had acute DVT, intend to do Catheter-Directed Thrombolysis (CDT, Percutaneous Mechanical Thrombectomy (PMT), or surgical thrombectomy.

4. The investigator determined that the patient had an appropriate femoral or jugular access for implantation of the filter.

5. The diameter of inferior vena cava intended to implant the filter is between 18mm and 29mm.

Exclusion Criteria:

1. Had been implanted with an inferior vena cava filter previously.
2. There is thromboembolism in the jugular or femoral vein access of the filter implantation.
3. Intended to permanently implant the filter.
4. Severe spinal deformity may affect the implantation or removal of filters.
5. Renal vein thrombosis, or, inferior vena cava thrombosis spread to renal vein.
6. Congenital malformation of inferior vena cava.
7. Having an uncontrolled infectious disease, such as bacteremia or toxaemia.
8. Active malignant tumour and tumour metastasis.
9. Allergic to imaging agents, materials of filters and conveyor (including nickel and titanium, polyester, Polytetrafluoroethylene (PTFE), nylon polymer materials).
10. Patients with X-ray contraindication.
11. Liver dysfunction: Alanine transaminase (ALT) or Aspartate transaminase (AST) was 2.5 times higher than the normal upper limit, Serum creatinine (Cr) was two times higher than the normal upper limit.
12. Abnormal coagulation function in patients: activated part of thrombin time (APTT)10s more than the normal value.
13. Patients with a life expectancy less than 12 months.
14. Patients with severe heart and lung dysfunction.
15. Pregnant or lactating, or woman planned to be pregnant.
16. The patients participated in clinical trials of other drugs or medical devices and did not come out of the group or withdraw within the first 3 months of the screening period of this trial.