A 52-year-old man underwent an uneventful directional atherectomy of the left anterior descending coronary artery. Four months after the procedure unstable angina developed and on angiogram an aneurysm of the left anterior descending coronary artery was noted. The patient underwent bypass of the left anterior descending coronary artery. An attempt to exclude the aneurysm resulted in hemodynamic compromise and was discontinued. Follow-up angiogram 2 months after operation showed the aneurysm to be smaller. The patient is doing well 6 months after operation.