Remodelling, defined as a change in total vessel area, was demonstrated to be another important mechanism of restenosis after coronary angioplasty in a study utilizing intravascular ultrasound. In this study, remodelling was also demonstrated to be bidirectional (constrictive modelling and adaptive remodelling). A recent serial intravascular ultrasound study revealed that time course of remodelling after coronary angioplasty was typically biphasic; early (post-procedure-1 month) adaptive remodelling and late (1 month-6 months) constrictive remodelling. Remodelling after coronary angioplasty should be regarded not only as a cause of restenosis but also as a mechanism maintaining patency.