Abstract 3043: Histopathological Findings of New In-Stent Lesions Developed Beyond 5 Years
We analyzed 14 cases of new lesions inside implanted bare-metal stents. In every case, there was no angiographic restenosis within 3 years, but a new lesion was observed inside a stented segment at long-term follow-up (>5 years). Fourteen cases were evaluated: 9 with Wiktor stents, 2 with Palmaz-Schatz stents and 3 with ACS Multilink stents. The interval from stent implantation to follow-up angiography was 63–147 months (89±23). Thirteen lesions were treated by percutaneous coronary intervention (PCI) and stenotic tissue was obtained by directional coronary atherectomy (DCA) in 10 cases. All retrieved samples were composed of newly developed atherosclerosis facing the healed neointimal layer, and 4 samples showed histopathological findings of acute coronary syndrome. Stent struts were retrieved in 4 cases and no inflammation was observed surrounding them. Qualitative and quantitative analysis of stent struts was performed in 2 cases that showed no metal corrosion. These findings suggest that new atherosclerotic progression occurred inside the implanted stent without peri-strut inflammation.