| Intracoronary stenting is widely used in the treatment of coronary atherosclerotic diseases.For decades,with the improvement of stents and surgical techniques by researchers and interventional doctors,especially the application of drug-eluting stents(DES),the incidence of in-stent restenosis(ISR)has been significantly reduced,but late ISR and in-stent thrombosis are the main complications that limit the application of DES.The wide application of coronary stents and the investigation of clinical application of stents in clinical trials make people have a deeper understanding and understanding of the risk factors of ISR.To explore the causes of ISR and find the corresponding coping strategies are the goals that researchers continue to pursue.Studies have shown that accelerating the process of endothelialization after stent implantation is an effective measure to prevent ISR.Based on this,the second chapter of this paper first explored the modification of polylactic acid coating on the surface of the stent by solution soaking on the basis of polylactic acid(PLA).The active factor glycogen synthase kinase 3? inhibitor(GSKi),was introduced by two different immobilization methods,one was through alkaline hydrolysis of polylactic acid and then electrostatic adsorption of GSKi,the other was immobilized by direct blending of polylactic acid and GSKi.The results showed that the two fixation methods had good biocompatibility.The results of endothelial cell proliferation showed that the composite bioactive coating immobilized bioactive molecule GSKi could obviously promote the proliferation of endothelial cells,and there was no statistical difference between the two fixation methods on endothelial cell proliferation.However,in the experiment,we found that the polylactic acid coating was difficult to form a thin and uniform coating on the surface of the stent,and after the stent was deformed by balloon stretching,the polylactic acid coating was obviously peeled off from the stent surface,and the stability and adhesion were poor.In order to solve the above problems,the third chapter of this paper further uses the polydopamine coating with stronger adhesion to the stainless steel substrate.At the same time,two active factors REDV and GSKi,were introduced into the surface of polydopamine coating by layer-by-layer dipping and coating,in order to overcome the shortcomings of a single active factor,in order to achieve the complementary advantages of many factors and play a greater role in promoting the endothelialization of stents.The blood compatibility test shows that the composite coating material has good blood compatibility.Cell experiments showed that compared with the coating with a single active factor,the composite coating material with the introduction of REDV and GSKi had a more significant effect on promoting the adhesion and proliferation of endothelial cells.The composite coating can form a uniform coating on the surface of the stent,and after the stent is deformed,the coating can firmly bond with the scaffold without obvious shedding and peeling off.The results of animal experiments show that REDV and GSKi composite coated stents can effectively accelerate endothelialization and reduce neointimal hyperplasia,so the composite coated stents are expected to have a good preventive effect on ISR.Promoting endothelialization of stents can reduce the incidence of in-stent restenosis,but in view of the complex causes of in-stent restenosis,the problem of instent restenosis can not be solved completely.only by knowing as much as possible about the risk factors of in-stent restenosis can we significantly reduce the incidence of in-stent restenosis.Therefore,the fourth chapter of this paper explores the occurrence of in-stent restenosis after stent implantation,which provides more theoretical basis for clinical prevention of in-stent restenosis.Twelve months after coronary stent implantation,the patients with ISR diagnosed by coronary angiography in the second Hospital of Jilin University were taken as the study object,and the patients without ISR as the control group.By collecting the basic clinical data and blood biochemical indexes of the patients,the differences of clinical basic data and blood test indexes between the ISR group and the non-ISR group were analyzed,and then the risk factors of ISR were confirmed by univariate and multivariate Logistic regression analysis.The results showed that there was no significant difference in clinical baseline data between the two groups.In terms of laboratory biochemical indexes,there were significant differences in leukocyte,low density lipoprotein cholesterol and urea nitrogen between ISR group and non-ISR group.Multivariate regression analysis showed that low density lipoprotein(OR=2.293,95%CI 1.183-4.445,P<0.05)and urea nitrogen(OR=1.688,95%CI 1.196-2.382,P<0.05)were the possible risk factors for the occurrence of ISR.This paper explored several methods of immobilization of bioactive molecules on coronary stents by polymer coating,studied the feasibility of composite coated stents in promoting endothelialization to prevent ISR,and analyzed the risk factors of patients with ISR after coronary stent implantation.These results are expected to provide more theoretical basis and technical support for reducing the occurrence of in-stent restenosis. |
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