A prospective, multi-center, randomized trial to assess the safety and effectiveness of Sirolimus-eluting Iron Bioresorbable Peripheral Scaffold System (IBS Titan™) in treating patients with infrapopliteal arterial stenosis or occlusive disease.

Inclusion Criteria:

1. Patients must between 18 and 85 years old, without gender limit.
2. Patients who can understand the purpose of the trial, voluntarily participate in and sign the informed consent form, and complete the 1-year follow-up.
3. Subject has lower extremity atherosclerotic occlusive disease with symptomatic Critical Limb Ischemia (CLI).
4. Rutherford Becker Clinical Category 3-5.
5. The target lesion is below the popliteal artery (including bifurcation).
6. The target lesion is located in the proximal 2/3 of native infrapopliteal vessels or tibiofibular trunk.
7. The target lesion stenosis is ≥70% or occlusion of no more than two infrapopliteal arteries (including the anterior and/or posterior tibial and/or peroneal artery and/or tibiofibular trunk).
8. The length of target lesion is ≤200mm, which could be covered by no more than two stents, with vessel diameter of 2.25-4.25 mm.

Exclusion Criteria:

1. Severe renal insufficiency, hepatic dysfunction (Cr>2 times of normal limit or renal dialysis, ALT or AST > 5 times of normal limit).
2. Surgery in target vessel before treatment.
3. Volume reduction surgery in target vessel before treatment.
4. Thrombosis in target vessel, or acute thrombosis requiring thrombolysis and thrombectomy.
5. Systematic coagulation disorder or hypercoagulability.
6. Lower extremity arteries surgery or thrombolytic therapy in the ipsilateral extremity in the past 6 weeks.
7. Stroke occurs within 3 months before surgery, or stroke occurs with severe hemiplegia aphasia sequelae more than 3 months before treatment.
8. Acute myocardial infarction or angina pectoris within 30 days before treatment.
9. In-stent restenosis.
10. Guide wire cannot pass target lesion.
11. Previously treated with drug eluting balloon within 1 year before treatment.
12. More than two infrapopliteal arteries needed treatment.
13. The inflow tract (including ipsilateral iliac artery, femoral artery, popliteal artery) has lumen stenosis >30% with or without intervention.
14. The inflow tract (including ipsilateral iliac artery, femoral artery, popliteal artery) has > 150 mm stenosis or occlusion before treatment.
15. Aneurysm of lower extremity artery.
16. Thromboangiitis obliterans (Buerger's disease).
17. Significant (≥ 50% stenosis) lesion in a distal outflow artery that would be perfused by the target vessel and that requires treatment at the time of the index procedure.
18. Patients known to be allergic to aspirin, heparin, Plavix, contrast agents, Sirolimus, poly lactic acid polymer, iron, zinc and their degradation product, and those who cannot tolerate postoperative dual anti-platelet therapy.
19. Patients who have a history of disease related to iron overload or iron disorder, such as hereditary hemochromatosis, etc.
20. Patients who are participating in another clinical trial that has not yet completed its primary endpoint.
21. Pregnant or those who plan pregnancy during the clinical investigation follow-up period.
22. Angiography suggests intraoperative thromboendarterectomy, percutaneous transluminal rotational atherectomy or laser therapy are needed.
23. Patients have life expectancy ≤ 1 year.
24. Patients who are not suitable for participating the trial judged by investigator.