A case of in-stent restenosis with pathologically proven chronic inflammation seven years after sirolimus-eluting stent implantation.

A 67-year-old man was admitted to our hospital due to chest pain at rest. Seven years previously, the patient underwent percutaneous coronary intervention (PCI) of the left ascending artery and implanted sirolimus-eluting stent (SES). Coronary angioscopy (CAS) performed at that time showed a white plaque at the SES site. Two years after the first PCI, repeat CAS demonstrated light yellow plaques at the SES site. At the time of his presentation to our hospital, coronary angiography showed in-stent restenosis at the SES site, and CAS demonstrated the plaque rupture with presence of dense yellow plaque and various thrombi. After distal protection, drug-eluting balloon treatment was performed. Collected specimens from culprit sites included foamy macrophages, cholesterin crystals, neutrophils, and fibrin, suggesting that progressive neoatherosclerosis at the SES site triggered the acute coronary syndrome. This study highlights the importance of ensuring careful patient follow-up after SES implantation. <Learning objective: After 1st generation drug-eluting stent implantation, careful follow up is warranted, as the process of neoatherosclerosis can be ongoing and contribute to in-stent restenosis.>.