Effect of vascular clamp on endothelial integrity of the internal mammary artery.

The preservation of endothelial integrity is essential for maintaining patency of vascular grafts. The internal mammary artery flow is often interrupted with the application of a soft vascular clamp to achieve a bloodless field during the anastomosis. We investigated the effect of the vascular clamp on the internal mammary artery endothelium using the scanning electron and light microscope. The endothelium was examined before and at 15 and 30 minutes after clamping in both the pedicled and the skeletonized arteries. Endothelial integrity was breached by clamping with early evidence of platelet adhesion to the damaged areas. The severity of the endothelial damage was related to the clamp time, but there was no difference in the degree of damage between the pedicled and the skeletonized arteries. We conclude that the vascular clamp causes injury to the internal mammary artery endothelium and may be implicated in early postoperative graft failure.