In-stent neoatherosclerosis: a final common pathway of late stent failure

Percutaneous coronary intervention with stenting is the most widely performed procedure for the treatment of symptomatic coronary disease, and drug-eluting stents (DES) have minimized the limitations of bare-metal stents (BMS). Nevertheless, there remain serious concerns about late complications such as in-stent restenosis and late stent thrombosis. Although in-stent restenosis of BMS was considered as a stable condition with an early peak of intimal hyperplasia, followed by a regression period beyond 1 year, recent studies have reported that one-third of patients with in-stent restenosis of BMS presented with acute coronary syndrome that is not regarded as clinically benign. Furthermore, both clinical and histologic studies of DES have demonstrated evidence of continuous neointimal growth during long-term follow-up, which is designated as "late catch-up" phenomenon. Here, we present emerging evidence of de novo neoatherosclerosis based on histology, angioscopy, and intravascular images that provide a new insight for the mechanism of late stent failure. In-stent neoatherosclerosis is an important substrate for late stent failure for both BMS and DES, especially in the extended phase. In light of the rapid progression in DES, early detection of neoatherosclerosis may be beneficial to improving long-term outcome of patients with DES implants.