A 64-year-old male with unstable angina underwent direct stenting in the proximal and mid-left anterior descending coronary artery (LAD) lesions. Although coronary angiography showed a good result, intravascular ultrasound imaging revealed a dissection flap protruding through the struts of the stent in the proximal LAD. Another stent was deployed in the first stent (stent-in-stent) to seal it. The patient's in-hospital course was uneventful. Subacute stent thrombosis was not observed.