Atresia of internal thoracic artery grafts following placement to noncritically obstructed vessels.

Four patients postcoronary bypass surgery, utilizing the left internal thoracic artery as a jump graft, were found to have atresia of either the proximal segment (2 patients) or the distal interposition segment (2 patients) of this graft. In all 4 cases the atretic portion of the graft was the segment that had been anastomosed to a noncritically obstructed vessel. The segment anastomosed to the severely narrowed portion of the vessel functioned normally and approximated the target vessel size.