Most pulmonary embolism (pulmonary infarction, pulmonary embolism, PE) is caused by a dislodged lower extremity deep vein thrombus (DVT) that travels with the blood through the inferior vena cava, the right heart, and then into the pulmonary artery, where the progressive thinning of the caliber of the branches of the pulmonary artery blocks the continued flow of the thrombus, resulting in pulmonary embolism, which in severe cases can be life-threatening.PE and DVT are often referred to together as VTE. Anticoagulation with heparin analogues or vitamin K antagonists is the mainstay of treatment for this condition. However, in some patients with DVT who have contraindications to anticoagulation and are unable to anticoagulate or have poor anticoagulation, 25% are at risk of fatalities. For such patients, inferior vena cava filters can be effective in reducing lethal PE. Currently, inferior vena cava filter implantation is absolutely necessary for the following patients (evidence-based medicine): 1. patients with VTE who have contraindications to anticoagulation; 2. patients with VTE who have severe anticoagulation complications; 3. patients with VTE who develop PE despite anticoagulation; and 4. patients with DVT who cannot achieve anticoagulation. Some other patients, depending on their condition, are also recommended for inferior vena cava filter implantation, such as: patients with poor compliance with anticoagulation therapy; patients with floating thrombus in the iliac vein or inferior vena cava; patients with DVT prior to DVT thrombolysis or thrombectomy; patients with VTE with very poor cardiopulmonary function; patients with VTE with high-risk anticoagulation complications; patients with recurrent PE with pulmonary hypertension; patients with VTE For some surgical and trauma patients with high risk of PE, prophylactic implantation of an inferior vena cava filter is also recommended to prevent PE.