Directional coronary atherectomy is a newly developed percutaneous transluminal procedure which excises and removes obstructive tissue from coronary arteries or saphenous vein grafts. This procedure was performed on 47 lesions with abnormal contour; 24 ulcerative lesions, 10 lesions with dissection, 7 flap-like lesions and 6 lesions with aneurysm dilatation. Overall success rate was 89%; 96% in ulcerative lesions, 70% in lesions with dissection, 86% in flap-like lesions and 100% in lesions with aneurysmal dilatation. Complications with this procedure were as follows: Vessel occlusion in 2 patients (4.5%), perforation in 1 patient (2.3%), and guiding catheter induced dissection in 1 patient (2.3%). Coronary artery bypass surgery was required in 4 patients (9.4%) for these complications. Of these, 3 patients had lesions with dissections prior to the atherectomy procedure. The success rate for lesions with abnormal contour was similar to those of 270 lesions with normal contour. In conclusion, directional coronary atherectomy is a safe and effective procedure for lesions with abnormal contour, however, outcome of a lesion with dissection is suboptimal and it needs to be approached cautiously.