A blockage at the stent can be implanted if the vessel is relatively thick in diameter, and no further stent can be placed in the stent of a relatively thin vessel. The treatment should be carried out according to the doctor’s instructions. Cardiac stents carry a risk of restenosis, which can lead to myocardial ischemia and can even induce myocardial infarction as well. Patients with in-stent restenosis should undergo coronary angiography to assess the severity of the condition. For thicker vessels, a stent can be re-implanted, and for thinner vessel diameters, a stent cannot be implanted. Re-insertion of a stent in a stent will reduce the diameter of the vessel. For thinner vessels, the risk of in-stent restenosis is very high with re-insertion of a stent in a stent, which can be treated with other methods, such as medicated ballooning, laser ablation, and so on. Patients with in-stent restenosis should be treated formally under the guidance of a physician, choosing the appropriate treatment according to the specific site of the lesion.