Background. Recurrent stenotic lesions associated with vein graft bypass grafts are often fibrous and smooth. Unlike de novo atherosclerotic lesions, they respond poorly to balloon angioplasty, and may often result in a dissection requiring stent placement to avoid early recurrent thrombosis or open repair of residual stenosis. A novel balloon designed with three or four longitudinally placed 0.127-mm atherotomes; was used at angioplasty to treat focal peripheral vein graft stenosis, in an attempt to minimize dissection by producing a controlled plaque fracture. Methods: Over 11 months, patients with focal (< 2 cm) peripheral vein graft stenosis underwent cutting balloon angioplasty (Boston Scientific, San Diego, Calif) at two separate centers. Baseline patient demographic data, type of bypass, velocity at pre-procedural and post-procedural duplex scanning, procedural results, complications, and type of long-term anticoagulation were recorded. Follow-up consisted of duplex ultrasound scanning at 1, 3, and 6 months and every 6 months for 2 years. Results: The mean age of the patients was 66.8 +/- 10 years. No intent to treat failure was noted. In most patients a 4-mm balloon was used (15 of 19) to treat 10 above-knee vein bypass grafts and 9 below-knee vein bypass grafts. No patient required placement of a stent or conversion to open surgery because of recoil, dissection, or suboptimal angioplasty. The mean velocity at pre-procedure duplex scanning at the site of vein graft stenosis was 373 +/- 56.8 cm/s, and the mean velocity post-treatment at 1-month follow-up was 144 +/- 50 cm/s. The mean length of stay was 26 +/- 32 hours. Overall, four patients continued to receive warfarin anticoagulation therapy, in addition to aspirin. During a mean follow-up of 11.4 +/- 7 months, recurrent stenosis developed in one patient. No other complications or graft recurrent thrombosis was noted. Conclusion: Cutting balloon angioplasty may help overcome hoop stress early, by producing a controlled, longitudinal neointimal lesion laceration and thereby facilitating a fracture line along predetermined microincisions. Our study results demonstrate acceptable early outcomes, with no requirement for bail-out stenting or open surgery.