Novel neointimal formation over sirolimus-eluting stents identified by coronary angioscopy and optical coherence...

Neointimal proliferation after sirolimus-eluting stent (SES) implantation is generally inhibited by the pharmacological effects of sirolimus in comparison to bare metal stent (BMS). Neointimal hyperplasia after BMS implantation is mainly composed of vascular smooth muscle cells, and is usually observed as a white mass by angioscopy and as a layer of uniform signal intensity without attenuation on optical coherence tomography (OCT). In this case, angioscopic color of the neointima covering the SES was obviously yellow and OCT signal patterns of the neointima showed rapid attenuation similar to lipid tissues in atherosclerotic lesions. These findings suggest that neointima within the SES is quite different from that of the BMS and may contain atherosclerotic components.