Characteristics of early versus late in-stent restenosis in second-generation drug-eluting stents: an optical coherence tomography study

In-stent restenosis (ISR) is an important cause of drug-eluting stent (DES) failure and target vessel revascularisation. In this study we aimed to evaluate differences between early and late-presenting restenosis in second-generation DES using optical coherence tomography (OCT).Overall, 171 cases of second-generation DES ISR with a follow-up OCT minimum lumen area <3.0 mm2 were included: 33.3% of patients (n=57) had early ISR, and 66.7% (n=114) had late ISR (duration from stent implantation >1 year). Minimum stent area (MSA) <4.0 mm2, neointimal thickness <100 µm, and heterogeneous neointimal hyperplasia (NIH) were more prevalent in early ISR, whereas NIH with neoatherosclerosis trended towards being more frequent for late ISR (28.9% vs. 15.8%, p=0.06). Multivariable analysis revealed that duration from implantation >2 years, absence of statin use, and NIH >50% were independent predictors for neoatherosclerosis (all p<0.05).OCT morphological characteristics of second-generation DES ISR differ between early and late presentation. Early ISR was associated with MSA <4.0 mm2, while neoatherosclerosis contributed more commonly to late ISR.