Failure of internal thoracic artery grafts: conclusions from coronary angiography mid-term follow-up.

Background: The objective of this study was to identify causes of the failures of internal thoracic artery bypass grafts according to operative technique, the internal thoracic artery used, and the coronary artery grafted.

Methods: This retrospective study concerns 302 follow-up angiographies performed in patients treated with 512 internal thoracic artery bypass grafts: 115 single grafts, 78 sequential grafts, and 109 grafts with two internal thoracic arteries (61 Y grafts). Postoperative angiography was performed after a mean period of 17.3 +/- 4.1 months.

Results: Failures consisted of 11 (2%) occluded grafts and 19 (4%) nonfunctioning grafts (threadlike internal thoracic artery). There was no difference in patency among the various types of left anterior descending artery bypass grafts anastomosed with the left internal thoracic artery. The failure rate was higher with the right internal thoracic artery (13%) than with the left internal thoracic artery (4%; p < 0.05). The failure rate of the left anterior descending artery bypass grafts (3%) was lower than that for the branches of circumflex artery bypass grafts (13%; p < 0.05). The 19 cases of nonfunctioning grafts did not include significant anastomotic stenosis: 14 were related to competitive blood flow, 4 to a poor recipient coronary arterial bed, and 1 to significant distal coronary stenosis.

Conclusions: At least two thirds of failures of bypass grafts could have been avoided by more objective analysis of the coronary stenosis on preoperative coronary angiography and better mastery of the surgical technique.