A 63-year-old man was hospitalized due to unstable angina and was subsequently implanted with a 4.0 × 28 mm third-generation sirolimus-eluting stent (SES) in the proximal left anterior descending artery (Panels A and B). Twelve months after implantation, he developed chest pain and underwent coronary angiography which revealed in-stent restenosis (ISR) (Panels C–E). Percutaneous coronary intervention was therefore performed. The ISR lesion showed iso and low echoic plaque on intravascular ultrasound (IVUS) (Panel F) and a layered pattern on optical coherence tomography (OCT) (Panel G). The lesion was resected using a novel directional coronary atherectomy (DCA) catheter (Panel H, post-procedural OCT). Histopathological analysis of the specimen retrieved by DCA showed myofibroblasts and a proteoglycan-rich neointima (Panel I1). Immunostaining also demonstrated that the neointima cells were mainly smooth muscle cells (α-smooth muscle actin) and a small number of macrophages (CD68) with endothelialization (CD31) (Panels I2–4). This is the first report to compare the histopathological findings of a restenotic lesion after third-generation SES implantation with IVUS supported by in vivo OCT images. Many histopathological studies after first-generation SES implantation have reported that the stent polymer causes rapid inflammation that frequently results in neoatherosclerosis. In order to reduce inflammation, third-generation SESs use a bioresorbable polymer that disappears within 12 months. Therefore, third-generation SES would be expected to accelerate complete endothelial recovery without neoatherosclerosis. The findings of the present case support previous in vivo findings and suggest that the restenotic pattern after third-generation SES implantation is histopathologically different from that observed after first-generation SES implantation.

中文翻译：

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第三代西罗莫司洗脱支架植入后的支架内再狭窄：根据成像方式和组织病理学发现分析的第一份报告。

一名63岁的男子因心绞痛不稳定而住院，随后在左前降支近端植入了一个4.0×28 mm的第三代西罗莫司洗脱支架（SES）（图A和B）。植入后十二个月，他出现胸痛并进行了冠状动脉造影，显示支架内再狭窄（ISR）（C – E组）。因此进行了经皮冠状动脉介入治疗。ISR病变在血管内超声（IVUS）上显示出同等和低回声斑块（图F），在光学相干断层扫描（OCT）上显示分层模式（图G）。使用新型定向冠状动脉粥样斑块切除术（DCA）导管切除病灶（H组，术后OCT）。DCA取回的标本的组织病理学分析显示成肌纤维细胞和富含蛋白聚糖的新内膜（图I1）。免疫染色也证实了新内膜细胞主要平滑肌细胞（α平滑肌肌动蛋白）和少量巨噬细胞（CD68）与内皮化（CD31）（面板I2 - 4）。这是第一份比较体内支持IVUS的第三代SES植入后再狭窄病变的组织病理学发现的报道OCT图片。第一代SES植入后的许多组织病理学研究均报道，支架聚合物会引起快速发炎，并经常导致新动脉粥样硬化。为了减轻炎症，第三代SES使用可生物吸收的聚合物，这种聚合物在12个月内消失。因此，第三代SES有望在没有新动脉粥样硬化的情况下加速内皮的完全恢复。本病例的发现支持先前的体内发现，并提示第三代SES植入后的再狭窄模式与第一代SES植入后的组织病理学不同。