Pathological analyses of very long-term sirolimus-eluting stent implantation in human coronary artery

Abstract

A 73-year-old man underwent sirolimus-eluting stent (SES) implantation for chest pain on exertion with left anterior descending coronary artery (LAD) and left circumflex coronary artery (LCX). The patient died due to non-obstructive mesenteric ischemia after 57 months of SES implantation. An autopsy demonstrated that the lesions of stented site at LAD and LCX were histopathologicaly similar images. In short, only mild neointimal formation with enough patent lumen was observed in all stented sites with no evidence of restenosis. In addition, complete coverage of endothelial cells in the surface of neointima was visible. Furthermore, necrotic core formation with a lot of circumferential cholesterol clefts was evident around the struts. In spite of these findings, observations of neointimal rupture and stent thrombosis were not found in this very late period autopsy study. In this histopathological examination, although neointimal coverage with enough lumen was observed, accumulation of extracellular lipid and cholesterol crystal was shaping necrotizing core, in short neoatherosclerosis. In the future, biocompatible drug-eluting stents which do not induce inflammation to the arterial wall post stenting should be appropriately addressed by the future development of improved coronary stents.