In-stent neointimal characteristics and late neointimal response after drug-eluting stent implantation: A preliminary observation

BackgroundProgressive neointimal proliferation may lead to late restenosis and/or neoatherosclerosis after drug-eluting stent (DES) implantation. Late neointimal response may be different among different tissue characteristics. The aim of this study was to assess impact of in-stent neointimal characteristics on late neointimal response following DES implantation.MethodsSerial (median 270 days and median 551 days after stent implantation) optical coherence tomography (OCT) examinations were performed in 42 stented lesions from 26 patients. In-stent neointimal tissue was categorized as either homogeneous or heterogeneous neointima based on the OCT appearance at 1st follow-up. Serial changes in neointimal area (NIA) were compared between lesions with homogeneous neointima and those with heterogeneous neointima.ResultsAt first follow-up, homogeneous neointima was observed in 22 (52%) and heterogeneous neointima in 20 (48%) lesions, respectively. During follow-up, NIA in lesions with homogeneous neointima decreased significantly (1.8 ± 0.93 mm2 to 1.5 ± 0.88 mm2, p < 0.001). On the other hand, NIA in lesions with heterogeneous neointima did not change significantly (2.7 ± 1.8 mm2 to 2.8 ± 1.6 mm2, p = 0.658). Homogeneous neointima was the only predictor of late neointimal regression (late neointimal regression defined as NIA at first follow-up – NIA at second follow-up <0) by multivariable analysis (odds ratio = 7.591, 95% confidence interval: 1.616–35.67, p = 0.010).ConclusionsOCT characteristics of neointima after DES implantation may be related to late neointimal progression or regression.