In-stent restenosis(ISR)and in-stent thrombosis(IST)are two major complications of percutaneous coronary in-tervention(PCI)and are also the main limiting factors in the treatment of obstructive coronary artery disease.In-stent neoathero-sclerosis(ISNA)serves as the common pathological basis for ISR and IST.Current research on ISNA is mainly based on clinical imaging observations using optical coherence tomography(OCT),angioscopy,intra vascular ultrasonography(IVUS),and autop-sy reports.The specific mechanisms and treatment strategies for ISNA are not clear yet.A comprehensive understanding of the epidemiological characteristics,histological features,and pathogenic mechanisms of ISNA not only helps in the prevention and treatment of post-stent complications,but also lays the foundation for the development of the next generation of coronary stents.This review summarizes the research progress on the development history of ISNA,the pathological features of ISNA,and the pathogenic mechanisms of ISNA.