This paper adopted UG8.0 to bulid the stent and blood vessel models. The models were then imported into the finite element analysis software ANSYS. The simulation results of ANSYS software showed that after endothelial stent implantation, the velocity of the blood was slow and the fluctuation of velocity was small, which meant the flow was relatively stable. When blood flowed through the endothelial stent, the pressure gradually became smaller, and the range of the pressure was not wide. The endothelial shear stress basically unchanged. In general, it can be concluded that the endothelial stents have little impact on the flow of blood and can fully realize its function.
Coronary atherosclerotic heart disease is a serious threat to human life and health. In recent years, the main treatment for it is to implant the intravascular stent into the lesion to support blood vessels and reconstruct blood supply. However, a large number of experimental results showed that mechanical injury and anti-proliferative drugs caused great damage after stent implantation, and increased in-stent restenosis and late thrombosis risk. Thus, maintaining the integrity and normal function of the endothelium can significantly reduce the rate of thrombosis and restenosis. Stem cell mobilization, homing, differentiation and proliferation are the main mechanisms of endothelial repair after vascular stent implantation. Vascular factor and mechanical microenvironmental changes in implanted sites have a certain effect on re-endothelialization. In this paper, the process of injury caused by stent implantation, the repair mechanism after injury and its influencing factors are expounded in detail. And repairing strategies are analyzed and summarized. This review provides a reference for overcoming the in-stent restenosis, endothelialization delay and late thrombosis during the interventional treatment, as well as for designing drug-eluting and biodegradation stents.
New biodegradable intravascular stent can reduce risk of foreign bodies retained, thus, it is widely concerned and some of the products have been introduced into the clinic. However, the characteristic of biodegradable may lead to more safety concerns associated with thrombosis. To ensure the safety, the thrombus formation experiment in vivo needs to be carefully designed and evaluated based on GB/T 16886.4 standard, but current standard do not provide explicit testing and evaluating methods. Establishing animal model with experimental pigs, the study compares biodegradable coronary stents and metal stents by simulating clinical implantation in vivo on the thrombus formation in the implanting process, and after the short-term and long-term implantation. The evaluation methods include gross observation, digital subtraction angiography intraoperative analysis, optical coherence tomography analysis, scanning electron microscopy and so on. The results show that combining these methods could comprehensively evaluate the whole process of the thrombus formation from the beginning of implantation to the end of preclinical animal experiments, so that, it may better predict the clinical thrombosis risk, and the selection of the control was very important. The study tries to use the comparison examples of thrombosis on the new medical instrument to provide the clue for thrombosis evaluation in vivo on similar instruments and show the methodology on the preclinical evaluation.