Background: The Cutting Balloon (CB) is a novel dilation device that longitudinally incises the coronary plaque during balloon dilation. This incision limits the degree of arterial trauma associated with balloon dilation, potentially reducing the late injury response compared with plain old balloon angioplasty (POBA).Methods: To evaluate the restenosis mechanism of CB in comparison with POBA, We performed intravascular ultrasound (IVUS) in 146 lesions (98 CB and 48 POBA) before and after the procedure and at a mean follow-up of 6 months. There were no significant differences in the patient and lesion characteristics between the two groups. Vessel area (VA), lumen area (LA) and plaque area (PA) were measured.Results: There were no differences among CB and POBA in pre and post changes in VA, LA and PA.Conclusion: In the restenosis group, there were no differences between CB and POBA. In the non-restenosis group, CB resulted in less plaque increase and plaque increase after POBA caused compensatory enlargement of coronary arteries, which may suggest a smaller degree of arterial trauma by CB.