1.Is there a stage or type of lower extremity deep vein thrombosis? A: The staging of lower limb deep vein thrombosis can be divided into acute, subacute, chronic and post-acute stages according to the time of onset. Generally, it is called acute phase within 7 days after the onset of the disease, chronic phase over 30 days, subacute phase between the two (8-30 days), and the sequelae phase when the symptoms of lower limb deep vein insufficiency appear around 3-6 months after the onset of the disease. Therefore, active treatment during the acute phase of onset has the best prognosis. The classification of lower limb deep vein thrombosis is divided into three types according to the location of the thrombus. 1.Peripheral type: deep vein thrombosis below the N vein, i.e., thrombosis below the knee joint and inside the calf; 2.Central type: iliofemoral vein thrombosis, i.e., venous thrombosis above the inguinal ligament; 3.Mixed type: total lower extremity deep vein thrombosis, i.e., the whole lower extremity vein is filled with thrombosis. There is also a special type of femoral cyanosis or femoral leukomalacia, which is the most serious case of lower limb deep vein thrombosis. When the reflux of the entire lower limb venous system is severely blocked, the tissue tension is extremely increased, resulting in arterial spasm of the lower limb and limb ischemia or even necrosis. In this case, the embolus must be surgically removed immediately to save the limb. 2.Traditional treatment methods mainly include anticoagulation, thrombolysis, surgical thrombosis, etc. According to the current information, why is anticoagulation the only recognized standard treatment? A: The latest international ACCP (American College of Chest Physicians) authoritative antithrombotic guidelines recommend anticoagulation as the first choice of treatment for lower extremity DVT, while the issue of thrombolysis and surgical clot retrieval has been controversial in the medical community. In China, many people have great expectations when they hear the tempting words “thrombolysis” and “clot retrieval”. In fact, this is only the ideal state literally understood rather than the inevitable outcome of treatment. There are four reasons for this: First, the clinical manifestation of venous thrombosis is lagging behind, and the thrombolytic drugs for mechanized thrombosis are ineffective and cannot be removed surgically; second, the bleeding risk of thrombolytic drugs is great, especially in elderly patients who may have fatal cerebral hemorrhage and gastrointestinal bleeding; third, a large number of comparative studies have shown that the therapeutic effect of thrombolysis is not better than anticoagulation; fourth, surgery is not able to remove all the thrombi in the veins, and the surgery is traumatic and destroys the formed thrombus. Fourth, surgery is not able to remove all the thrombus in the vein, and the surgery is more traumatic and destroys the formed collateral circulation. Of course, for the above mentioned special types of femoral cytomas or femoral leukomas, surgery must be preferred to remove the thrombus. With the development of interventional technology in recent years, further experience is still being accumulated as to whether the development of cannulated thrombolysis can reduce complications and improve the therapeutic effect. From the current clinical results, it is still relatively optimistic, but the indications should be strictly controlled. 3.Which patients are suitable for anticoagulation therapy and which are not? A: Anticoagulation is the first choice for treatment of lower extremity deep vein thrombosis, and its role is to prevent further spread of thrombus or formation of new thrombus, to open the lateral circulation to relieve symptoms. Anticoagulation therapy is available for most of the population, but patients with the following conditions are not suitable for anticoagulation therapy: 1. contraindicated or allergic to anticoagulant drugs; 2. active internal bleeding, including severe intracranial, gastrointestinal and urinary tract bleeding; 3. recent history of cerebrovascular accident; 4. recent severe trauma; 5. recent major surgery; 6. severe hypertension; 7. severe hepatic and renal insufficiency; 8. 8.Patients with congenital coagulation factor deficiency, etc.