Very late stent thrombosis after paclitaxel-eluting stent implantation with full neointimal tissue coverage visualized by optical coherence tomography.

We present findings of a very late stent thrombosis (VLST) involving paclitaxel-eluting stents (PESs) that were fully covered by thin neointima, visualized by optical coherence tomography (OCT) in a patient receiving dual antiplatelet therapy. A 69-year-old Japanese man had been treated with 2 overlapping PESs for chronic coronary artery disease in the proximal right coronary artery. A follow-up coronary computed tomography angiography showed no restenosis in the stent site, and the result of stress myocardial perfusion imaging showed no ischemic changes. Seventeen months after the percutaneous coronary intervention, he was transported to our clinic with a diagnosis of acute myocardial infarction. Emergency coronary angiography showed a total occlusion at the overlapping site of the 2 PESs. After thrombus aspiration therapy, the OCT image revealed a thin layer of neointimal tissue covering the stent struts with no stent malapposition or fracture. There was no plaque rupture site or intracoronary thrombus. Histopathologic study of an aspirated red thrombus revealed massive amounts of inflammatory infiltrates including eosinophils and neutrophils within the fibrin clot. These findings suggested the possibility that the patient's allergic and inflammatory reactions may have caused the onset of VLST. <Learning objective: To recognize the relationship between in stent OCT findings of neointima and pathological findings of the thrombus at the VLST after PES implantation.>.