This is a Prospective randomized controlled study to evaluate the difference of safety，effectiveness between chocolate balloon and plain balloon dilatation in treatment of infrapopliteal artery lesions.

Prospective randomized controlled study to evaluate the difference of safety，effectiveness between chocolate balloon and plain balloon dilatation in treatment of infrapopliteal artery lesions. Patients with femoral-popliteal artery lesions in our department were randomly assigned to the chocolate balloon group and plain balloon dilatation group. Compare the ischemic improvement rate (limb salvage rate, postoperative patency rate) and the complications rate of two different treatments.

Inclusion criteria： 1.all patients signed an informed consent form; 2.digital subtraction angiography (DSA) revealed femoropopliteal artery stenosis above 70% or occlusion resulting in claudication (Rutherford clinical category-Becker class II-III2-3) or critical limb ischemia (CLI) (Rutherford clinical category 4-5-Becker class IV-V) 3.with unobstructed vascular inflow; 4.with at least a vessel runoff; 5. good compliance and regular follow-up.

Exclusion criteria: 1. Acute or subacute lower limb ischemia caused by acute intraluminal thrombus within the target lesion.; 2. Severe calcified lesions （grade 4 in the PACSS scale）; 3. In-stent restenosis lesion or surgical arterial bypass grafting; 4. Severe renal insufficiency: creatinine level greater than 2.5 mg/dL; 5. Platelet count below 100,000/μL or with antiplatelet / anticoagulation contraindications; 6. Immunologic diseases or malignant diseases; 7. Ongoing active infection; 8. Decompensated congestive heart failure or acute coronary syndrome; 9. Refuse to sign the informed consent Unwillingness to comply with follow-up suggestions.