Stent malapposition occurred 17 days following percutaneous coronary intervention for a severe calcified lesion in acute myocardial infarction.

The occurrence of stent malapposition and coronary artery aneurysm (CAA) during the early phase of drug-eluting stent (DES) implantation is rare. This report presents the case of a 55-year-old man who underwent DES implantation to the left circumflex artery with full-arc severe calcified lesion owing to inferior acute myocardial infarction. Coronary angiography and optical coherence tomography (OCT) at 17 days following percutaneous coronary intervention (PCI) revealed stent malapposition and CAA of diameter 6.5 mm in the distal part of the stented vessel. OCT findings at 5 months following PCI revealed a dilated CAA of diameter 7.5 mm and a luminal structure outside the stent. Based on these findings, it was suggested that the cause of CAA in the early phase following DES implantation to the severe calcified lesion was related to coronary sequelae of Kawasaki disease. < This was a case of coronary artery aneurysm (CAA) in the stented lesion at early phase post percutaneous coronary intervention (PCI). Despite the patient's young age and low coronary risk, there was full-arc severe calcification lesion. Optical coherence tomography after PCI showed luminal structure outside of the stent. It was similar to recanalized CAA of Kawasaki disease (KD). These findings suggested that CAA in early phase following PCI might be related to the sequelae of coronary arteritis, especially KD.>.