Comparison of endothelial function between in situ and reversed vein graft: differences in endothelium-dependent responses.

BACKGROUND

The endothelium releases endothelium-derived relaxing factors that are potent vasodilators and inhibitors of platelet aggregation. Experiments were performed to determine whether the endothelium-dependent responses differed between in situ and reversed vein grafts. The influence of valve disruption or of dissection of the adventitia was also examined.

METHODS

Segments of canine jugular veins were grafted into the carotid arteries during procedures such as reversed grafting, in situ grafting with valve disruption, in situ grafting without valve disruption, and in situ grafting with dissection of adventitia. After 4 weeks the endothelium-dependent responses of the grafts were examined by isometric tension recording.

RESULTS

In the reversed and in situ vein graft with valve disruption, acetylcholine caused endothelium-independent contractions, whereas in the in situ vein graft without valve disruption acetylcholine-induced endothelium-dependent relaxations were preserved. Adenosine diphosphate (ADP) caused comparable endothelium-dependent relaxations in the in situ vein graft irrespective of valve disruption. In the reversed vein graft ADP-induced relaxations were significantly impaired. In the in situ vein graft with dissection of the adventitia, relaxations in response to acetylcholine and ADP were significantly reduced.

CONCLUSIONS

These results suggest that endothelial function, in terms of endothelium-derived relaxing factors in the in situ vein graft, can be preserved and that adventitial dissection in the in situ vein graft should be minimized to preserve endothelial function.