The comparison of traditional and modified harvesting techniques of left internal mammary artery regarding endothelin-1/2/3 expression and free flow capacity

Aim. We have conducted this study to seek and observe visual clues through immunohistochemical staining for differences in Et-1/2/3 expression and the free-low capacity measuring the blood flow through grafts, in the left internal mammary artery grafts prepared either with clipped or nonclipped techniques. Methods. A total of 40 consecutive patients with a diagnosis of coronary artery disease who would benefit from elective coronary artery bypass graft surgery were randomised into two groups consisting 20 patients each. Left internal mammary artery was harvested by a traditional clipped (control group) and a modified nonclipped (study group) technique in each of the groups. All harvested arterial segments were evaluated for luminal endothelial integrity through hematoxylin&eosin and immunohistochemical staining. Results. The free-low capacity of left internal mammary artery grafts were significantly higher in nonclipped arteries when compared with that of clipped ones (P=0.001). The arterial lumen of the nonclipped segments were visibly more dilated than the clipped ones. Nonclipped segments presented a lighter immunostaining for Et-1/2/3 when compared with the clipped ones (P<0.001). Conclusion. We believe that lesser endothelial damage caused by the lower intraluminal pressure in modifiedly harvested left internal mammary artery segments has positive implications on intraoperative and postoperative cardiac events related to graft vasospasm, especially related with endothelins. We recommend modified left internal mammary artery harvesting in patients going under coronary artery bypass graft operation.