When a severe stenosis or occlusion of an artery is dilated by a balloon, a stent must be implanted to improve blood flow in the presence of >30% residual stenosis or a clamping that restricts blood flow. However, after the stent is implanted in the human body, it is a foreign body in the human body. When your previous underlying pathologies, such as diabetes, hyperlipidemia, renal insufficiency, etc., are not well controlled, or you do not take anticoagulant drugs as required by your doctor, or smoke, the endothelial cells of the artery at the stent implantation site and the smooth muscle cells of the middle membrane are extremely prone to overproliferation and often combined to form thrombus, which in turn causes restenosis or even occlusion in the stent. This is one of the world’s medical problems. After restenosis occurs in the stent, as the lesion progresses, it is easy to occlude again, and the original lower limb ischemic symptoms will reappear, what should we do? The doctor can treat the patient according to the following methods according to the materials and technology he has at present: 1.Replacing the stent with a balloon, especially a cut balloon, according to the previous method. 2.Ablation and cutting of the overgrown tissue in the stent with laser ablation or plaque cutting device to achieve stent recanalization. 3.The lesion in the stent is dilated again using ordinary balloon first, and then, drug-coated balloon expansion or drug-coated stent implantation (i.e., drugs that inhibit excessive proliferation of endothelial cells and smooth muscle cells are coated on the surface of the balloon or inlaid in the stent to inhibit restenosis in the stent through slow release of drugs) is used to achieve stent recanalization. 4.After dilating the stenosis or occlusion in the stent with a common balloon, radioactive material is injected into the balloon to perform local close internal irradiation in the stent to achieve stent recanalization. 5. Vascular bypass is performed. Usually, the first and second methods have good results in the near future (3 months) after treatment, but the recanalization rate after 6 or 12 months is only about 50%, which means that nearly half of the patients have their blood vessels blocked again after 6 or 12 months after treatment; and vascular bypass surgery is very traumatic and risky, and it is difficult to tolerate the surgery when the heart, liver, kidney, lung and other organs are damaged, and there are many postoperative complications (bleeding, migration, etc.). There are many postoperative complications (bleeding, graft occlusion, fistula, cardiovascular accidents, etc.), and when there is no ideal saphenous vein with artificial vessels as grafts, the medium and long-term patency rate is also greatly reduced. The third and fourth methods, however, not only have satisfactory results in the near future, but also have a recanalization rate of 83% and 87% respectively at 12 months after surgery, which is a very promising treatment method. On the downside, the cost is more expensive.