String phenomenon of the internal mammary artery graft, caused by competitive flow of the left anterior descending artery because of regression of the left anterior descending artery lesion. A: Severe stenosis (as a consequence of non-occlusive thrombus formation associated with a ruptured plaque) on the left anterior descending artery (black arrow) just under the origin of a well-developed diagonal branch (left striped arrow), and on an obtus marginal of the left circumflex artery (right striped arrow). B: Three years after the bypass surgery, the contrast injection of the left coronary artery shows retrograde filling of the degenerated left internal mammary artery graft (white arrow). There is no significant stenosis at the site of the original lesion (black arrow), presumably because of the healing of the ruptured plaque with resolution of the thrombus. After the bypass surgery, the grafted diagonal and marginal branches became occluded, but the applied venous grafts provided good filling of the run-off (C: striped arrows).