OBJECTIVE: To determine the mid-term effects of cutting balloon angioplasty (CBA) on in-stent restenosis. METHODS: A total of 69 patients with in-stent restenosis were divided into 2 groups randomly: cutting balloon angioplasty and plain old balloon angioplasty. The mechanisms of restenosis and dilation results were determined by quantitative coronary angiography and intravascular ultrasound. Follow-up was performed. RESULTS: The procedural success rate was 100% without death and acute closure. One patient experienced dissection at the distal end of the stent and needed another stent. The mean follow-up period was 6.7 +/- 2.3 months. The final re-restenosis rate was 15% and 18% at 3 months and 6 months respectively, markedly lower than after plain old balloon angioplasty (38% and 43%). Acute gain by intravascular ultrasound (IVUS) was 1.72 +/- 0.52 mm after cutting balloon angioplasty, higher than 1.15 +/- 0.54 mm after plain old balloon angioplasty. The lumen diameter late loss in the cutting balloon group was 0.26 +/- 0.05 mm and 0.38 +/- 0.06 mm at 3 months and 6 months respectively, significantly lower than for those in conventional balloon group (0.78 +/- 0.19 mm and 0.89 +/- 0.16 mm, respectively, P
