[Failure of internal thoracic-coronary artery bypass graft. What are the reasons?].

The aim of this study was to identify the causes of failure of coronary bypass grafting with the internal thoracic artery. A total of 512 internal thoracic artery grafts in 302 patients were reviewed. Control coronary angiography was performed after an average of 17.3 months (sigma = 4.1 months). Were considered as failures: 11 (2%) occluded grafts and 19 (4%) non-functional (narrowed internal thoracic artery) grafts. The appearances of the anastomosis, presence or absence of stenosis, origin of flow at the anastomosis and distal run-off of the grafted coronary artery, were analysed. Of the 19 non-functional grafts, there were no stenosis of the anastomosis of the narrowed internal thoracic arteries; in 14 cases, competitive flow was observed (2 internal thoracic artery steal syndromes by non-obstructed proximal collateral branches, 8 initially overestimated coronary stenoses, 4 secondary regressions of coronary stenosis); there was poor distal run-off of the grafted artery in 4 cases and significant coronary stenosis distal to the graft in one case. This study shows that, of the 30 failures of internal thoracic artery grafting, at least 2/3 were "avoidable" by a more accurate evaluation of the coronary stenosis on the preoperative coronary angiography and by better surgical technique.