Inclusion Criteria:  Patients over 18 years old. acute or subacute limb ischemia patients with Rutherford classification stage range from I to IIb. Patients with Rutherford classification range from 3 to 5. The guide wire should pass through the lesion of femoropopliteal artery, and further endovascular treatment is performed. In this study, we did not limit the methods of the guide wire passing through the target lesion. After the angiography and/or performed under digital subtraction angiography(DSA) which confirmed the existing of thrombus, and which is related to occlusions of lower extremity or in-stent restenosis. Pharmacomechanical thrombectomy (PMT) and/or catheter-directed thrombolysis (CDT) was or were used for thrombus removal. The lower extremity artery needs to have a healthy runoff of no less than 10 cm above the ankle, and at least one healthy dorsalis pedis artery, medial or lateral plantar artery connected with the digital artery below the ankle. Informed consent signed by patients.  Exclusion Criteria:  acute or subacute limb ischemia patients with Rutherford classification stage III. Patients with thromboangiitis obliterans. Patients with failure of endovascular treatment, and transfer to open surgery or hybrid operation. People with stroke, cerebral hemorrhage, gastrointestinal bleeding or myocardial infarction and so on in the past 3 months. Patients with known allergy to heparin, low molecular weight heparin and contrast agents. Patients with high bleeding risk. Women during pregnancy and lactation. Patients with other diseases that may lead to difficulties in the trial or significantly shorten the life expectancy (< 2 years), such as tumors, severe liver disease, cardiac insufficiency. Patients who have been enrolled in other clinical trials in the past 3 months.  Patients who are unwilling or refuse to sign the informed consent form.  -