Left leg venous thrombosis can not always be completely dissolved. Old left leg vein thrombosis, after lower limb angiography, the degree and location of stenosis can be clarified, generally cannot be lysed successfully, long-term use of anticoagulant drugs (such as rivaroxaban) is required. Fresh venous thrombosis, timely completion of lower limb angiography, according to what is seen in the operation, given urokinase, alteplase and other drugs thrombolysis, unsuccessful can be considered to remove the embolus, most of the thrombolysis can be successful, and a small portion of the thrombolysis failure can also occur, and even appear life-threatening. Thrombolytic surgery has advantages and disadvantages, in the thrombolytic operation should be repeated with the patient and his family to explain the necessity and the related risks, after signing the consent can be carried out by a professional doctor. Consult the doctor in time if you feel unwell.