OBJECTIVE: To explore the pharmacological treatment of lower limb deep vein thrombosis. Methods: Retrospective analysis of 98 cases of lower extremity deep vein thrombosis treated with drugs between December 2005 and October 2010 in Aviation General Hospital and Second Artillery General Hospital, including 60 cases of left lower extremity deep vein thrombosis, 33 cases of right lower extremity deep vein thrombosis and 5 cases of double lower extremity deep vein thrombosis, all patients were diagnosed by lower extremity vascular ultrasound. ～All 98 patients were treated with urokinase 7~10 days by intravenous infusion of urokinase, 250,000~500,000 U/day, and all of them were treated with low molecular heparin sodium anticoagulation for 10~14 days, 4000~6400 U, subcutaneous injection, Q12h; 26 of them were placed with inferior vena cava filter before thrombolysis. Anticoagulation therapy was continued with warfarin and/or aspirin for 5 to 26 months after discharge. RESULTS: All 98 patients had relief of limb swelling and pain symptoms and were successfully discharged from the hospital. No bleeding complications occurred during drug treatment, among which 6 cases of pulmonary embolism occurred and 4 cases of symptomatic pulmonary embolism improved after thrombolysis and anticoagulation. 82 cases were followed up for 1 month to 4 years with a mean of 11.2 months. Conclusion Urokinase supplemented with low molecular heparin sodium is safe and effective in lower extremity deep vein thrombosis. Placement of an inferior vena cava filter needs to be patient-specific. Acute deep venous thrombosis (DVT) is clinically common and can lead to pulmonary embolism (PE) and common post-DVT syndrome in severe cases, which can seriously affect quality of life or even endanger life. From December 2005 to October 2010, 98 patients with DVT of lower limbs were treated with urokinase thrombolysis and low-molecular heparin anticoagulation in Aviation General Hospital and Second Artillery General Hospital. 1, clinical data (1) general data The group of 98 cases, 62 men and 36 women. Age: 21-95 years old, mean age: 53.6 years old. Among them, there were 60 cases of left lower limb DVT, 33 cases of right lower limb DVT, 5 cases of double lower limb DVT; 56 cases of central type, 20 cases of peripheral type and 22 cases of mixed type. The onset time ranged from 2 hours to 27 days, with an average of 3.2 days. Clinical manifestations: lower limbs swelling, pain, limitation of movement, increased skin temperature of the affected limbs, the circumference of the upper 15 cm of the knee joint was 3.7-11.9 cm longer than that of the healthy side, with an average of 6.7 cm, and the circumference of the lower 10 cm of the knee joint was 2.0-8.9 cm longer than that of the healthy side, with an average of 3.1 cm. 24 cases had no obvious cause for the onset of the disease, 38 cases had surgery, and 36 cases were bedridden for a long time. All patients were confirmed to have iliofemoral or superficial femoral vein thrombosis by lower limb vascular ultrasound and laboratory examination. (2) Treatment method: 98 cases were given pure drug thrombolytic anticoagulation therapy according to the patients’ willingness. Urokinase was infused through the dorsal foot vein after the pressure was applied to the affected limb, firstly, a cannula needle was left in the superficial vein of the dorsal foot of the affected limb, and then an elastic bandage was applied above the ankle joint (the pressure was based on 1/3 of the fully expanded elastic bandage) to promote the drug to enter the deep vein and fully flow through the surface of the thrombus to reach the maximum drug effect. Add 250,000~500,000 Urokinase to 50~100ml saline, push or infuse from the dorsal foot vein for 30~60min, once~2 times/day, for 7~10 days, total 3.5~6.5 million Urokinase, supplemented with 4000~6400U of low molecular heparin sodium, subcutaneously, once every 12 hours. Warfarin 5 mg/day was added after 10 days of treatment, and the low-molecular heparin sodium was discontinued after 2-3 days of overlapping with warfarin. The prothrombin time internationalization standard ratio (PT-INR) was monitored daily, and the warfarin dosage was adjusted according to the INR test results to control the INR at about 2.0-2.5. The prothrombin time, activated partial thromboplastin time and fibrinogen were tested regularly throughout the treatment, and the drug was promptly reduced or stopped and treated symptomatically if there was a bleeding trend. Among them, 19 patients with central and mixed DVT in the right lower extremity and both lower extremities underwent inferior vena cava filter (IVCF) placement before thrombolysis, 16 through the left femoral vein and 3 through the jugular vein. All patients were discharged from the hospital on long-term anticoagulation therapy for 5 to 26 months, including 86 cases of oral warfarin and 12 cases of aspirin, and 67 cases who insisted on wearing medical circular elastic stockings. The patients were followed up regularly with lower extremity vascular ultrasound and D-dimer examination to determine whether there was any recurrence of thrombosis. 2.Results After 10 days of thrombolytic and anticoagulant treatment, the swelling, pain, restricted activity, elevated skin temperature and superficial varicose veins of the affected limbs were significantly relieved in 98 patients, and the skin temperature of the affected limbs returned to normal in 1-4 days after treatment, and the swelling and pain of the lower limbs were relieved in 1-8 days after treatment. The swelling could be significantly relieved after bed rest or wearing elastic stockings. All patients had no local spillage of fluid during dorsal foot vein infusion, but there was a tendency of bleeding at the puncture site after releasing the superficial vein compression, which often required 15-30 min of pressure. Among the other patients without IVCF implantation, there was one case of asymptomatic PE in a patient with DVT of the right lower extremity, which was detected during the follow-up chest CT examination; one case of DVT of both lower extremities with inferior vena cava thrombosis developed symptomatic PE during treatment because the patient’s family refused to place the filter; four patients with symptomatic PE presented with chest pain and shortness of breath and were thrombolized by urokinase (500,000 units intravenous push/30 min, 500,000 units intravenous drip/6-8 h). Eighty-two patients were followed up for 1 month to 4 years, with a mean of 11.2 months, and 16 patients were lost. 82 patients were treated with warfarin and/or aspirin anticoagulation for a long time, and no DVT recurred. 15 of them had swelling of the lower limbs after activity, but it was significantly relieved by wearing elastic stockings. All patients returned to normal life. 3.Discussion With the improvement of people’s awareness of DVT and detection means, DVT of lower limbs has become a common and frequent clinical disease. According to incomplete statistics, there are 150,000 people with pulmonary embolism due to this disease in the United States every year [1], and there is a lack of relevant statistics in China. Acute lower extremity DVT formation is mostly due to slow blood flow and blood hypercoagulation, and is also associated with oral contraceptives and protein S deficiency [2]. Our group of 98 patients included acute (within 7 days) and subacute cases (7-30 days), mostly post-surgical and long-term bedridden patients, and the diagnosis was rapidly confirmed according to the patients’ clinical manifestations and ultrasound. In recent years, some scholars have reported good results in the treatment of acute lower extremity DVT thrombosis by emergency surgery, direct thrombolysis by catheter placement and percutaneous mechanical thrombus extraction. Although minimally invasive, they still aggravate the psychological and economic burden of patients to varying degrees. Chen Hongqiang [5] et al. retrospectively analyzed the data of 126 patients with acute lower extremity DVT treated non-operatively, and the results showed that 85 cases (67.5%) were clinically cured, 34 cases (27.0%) were good, and the total effective rate was 98.4% (124/126), and pointed out that the majority of patients with lower extremity DVT could achieve satisfactory therapeutic results by non-operative treatment based on thrombolysis and anticoagulation, and the key The key is early diagnosis and early rational use of drugs. All 98 patients in this group had no contraindications to fibrinolysis and bruising of the femur, and they were treated with non-operative treatment based on thrombolysis and anticoagulation according to the patients’ wishes, and good results were achieved. We believe that the treatment of acute lower extremity DVT should be done quickly after the diagnosis of urokinase thrombolysis and low-molecular heparin sodium anticoagulation therapy, and combined with low-molecular dextrose depolymerization therapy; the route of administration and dosage are also very important, and the earlier the thrombolysis of acute lower extremity DVT, the better the effect [6-8]. In this group, urokinase was given via the dorsal foot vein of the affected limb after diagnosis, and a compression bandage was applied to the calf above the ankle to facilitate the entry of the drug into the deep vein. In view of the current medical policy and treatment requirements, it is not possible to give the contrast agent at the same time as the patient’s drug infusion to prove that the drug does enter the vein with thrombosis, but according to our experience of doing lower extremity paracentesis, the pressure bandage range from the upper ankle to the knee level can make almost all of the drug enter the deep vein. In addition, according to our previous experience, local administration of the drug to the affected limb can reduce the dosage of the drug, bleeding complications and significantly shorten the time to swelling of the limb, but no controlled study has been conducted in this regard. The dosage of urokinase is not yet uniformly prescribed at home and abroad, and most foreign scholars use high-dose shock therapy [7]. None of the patients in this group had serious complications such as bleeding during thrombolysis, indicating that this dose of urokinase is safe for normal weight patients. Anticoagulation therapy is commonly used for DVT, and timely and regular anticoagulation reduces the recurrence rate of venous thrombosis from 29% to 47% to 5% to 7% and the risk of fatal pulmonary embolism by 10.4% to 1.5%. Low-molecular heparin is preferred and later supplemented with warfarin anticoagulation to control INR between 2.0 and 2.5 is sufficient. Warfarin is recommended as the first choice. The authors have had 2 cases of pulmonary artery thrombosis that disappeared after several months-1 year of warfarin in patients who had been previously examined, and the reason is not well understood. Some of the patients in this group were changed to aspirin anticoagulation therapy because of warfarin allergy or inability to insist on long-term review of INR, and some patients were added to aspirin because INR could not reach 2.0-2.5 even when warfarin dosage was high. Acute DVT is often treated with bed rest and elevation of the affected limb, but for chronic DVT, the rate of pain and swelling resolution is significantly faster with appropriate exercise than with bed rest. For active lower extremity edema due to post-DVT syndrome, circulating compression stockings or intermittent compression therapy is recommended. The placement of IVCF is still controversial, but compared to the other invasive methods we have done, all of which require the placement of a filter, the placement of a vena cava filter for pharmacological thrombolytic anticoagulation of lower extremity thrombosis is the least common. However, we should still be very alert to the serious complications that may result once it occurs. In our opinion, temporary inferior vena cava filters should be placed to prevent pulmonary embolism in central type with floating thrombus, especially in the right side, and other indications for filter placement should also be noted; especially in the current domestic medical environment, patients and their families should be fully informed of the chance of complications and the severity of their occurrence, and patients’ wishes should be respected. Therefore, IVCF can effectively prevent PE, but the indications should be strictly controlled. Because there is a higher tendency of DVT recurrence in patients with filter placement as time increases. For most DVT patients, routine application of vena cava filters is not recommended in principle. In conclusion, the treatment of acute lower extremity DVT can still achieve good results with early and appropriate application of urokinase thrombolytic therapy and low-molecular heparin anticoagulation compared with minimally invasive surgery on the basis of following treatment principles, and the indications for IVCF placement should be strictly controlled. At present, there is a lack of uniform understanding of the treatment of DVT in the lower extremities, and there are great differences in the treatment methods and long-term efficacy, so it is necessary to further standardize the treatment strategy of acute lower extremity DVT.