Mechanism of Drug-Eluting Stent Thrombosis Diagnosed by Histopathological Evaluation of Directional Coronary Atherectomy Specimen.

An 89-year-old man with a history of percutaneous coronary intervention using a sirolimus-eluting stent presented with recurrent in-stent occlusion. Pathological assessment of the neointima resected via directional coronary atherectomy revealed a double-layered thrombus. Clopidogrel resistance and limited antithrombotic regimen owing to high bleeding risk likely resulted in the in-stent thrombotic occlusion.