Guidewire snap causing left main coronary occlusion during coronary angioplasty.

The case of a 34-year-old female patient is presented. During attempted left anterior descending coronary angioplasty, the exchange guidewire (0.018 inch, 300 cm) snapped and the distal 20 cm of the wire caused immediate thrombotic occlusion of both the left anterior descending and circumflex arteries. The resulting complication was treated by emergency bypass surgery.