[Analysis of optical coherence tomography of early and very late stent restenosis after drug-eluting stent implantation].

Objective Using optical coherence tomography (OCT) to analyze the morphological characteristics of lesions between early in-stent restenosis (E-ISR) and very late in-stent restenosis (VL-ISR) after drug-eluting stents (DES) implantation. Methods In 25 patients (DES) with ISR, OCT images were acquired before percutaneous coronary intervention (PCI), the morphological characteristics of E-ISR ( 3 years, n=11) were compared.The quantitative and qualitative analysis of the entire stent and the minimum lumen area (MLA) site were carried out respectively. OCT quantitative restenotic tissue analysis included the assessment of mean lumen area, mean stent area, mean neointimal area and mean neointimal burden.OCT qualitative restenotic tissue analysis included the assessment of tissue structure [homogeneous or heterogeneous intima (lipid-rich neoitima, thin-cap fibroatheroma (TCFA)-like intima)], presence of microvessels, intraluminal material (red thrombus, pale thrombus), disrupted intima with cavity and tissue prolapse and was performed at every 1-mm slice of the entire stent. Results Compared with the E-ISR group, the proportion of cross-sections with heterogeneous intima in the entire stent was significantly higher in the VL-ISR group (60.57% vs 32.93%, P=0.005), and both peristent and intraintimal microvessels were more frequently observed in the VL-ISR group (P<0.05). In addition, lipid-rich neointima (72.7% vs 21.4%, P=0.017), TCFA-like intima (54.5% vs 7.1%, P=0.021), disrupted intima with visible cavity (63.6% vs 7.1%, P=0.007) and red thrombus (63.6% vs 7.1%, P=0.007) were observed more frequently in the VL-ISR group compared with E-ISR group for the entire stent.The heterogeneous intima was observed more frequently in the VL-ISR group (90.9% vs 35.7%, P=0.012) at the MLA sites.Intraintimal microvessels and disrupted intima with visible cavity were observed only in the VL-ISR group. Conclusions OCT imaging indicates that the morphological characteristics of restenosis lesions in VL-ISR are different from those in E-ISR.The atherosclerotic changes of neointima, such as lipid-rich neointima, disrupted intima with cavity and microvessels are more often observed in VL-ISR lesions after DES implantation compared with E-ISR.Progression of the atherosclerosis within neointima after DES implantation may be associated with VL-ISR. Key words: Drug-eluting stent; Optical coherence tomography; Restenosis