EARLY ALTERATIONS IN VASCULAR REACTIVITY OF AUTOGENOUS SAPHENOUS-VEIN GRAFTS

Background: The present study examined the in vitro reactivity of vein bypass grafts 1 week after graft placement. Methods: Saphenous vein grafts were implanted into the carotid artery by the reversed end-to-end technique in mongrel dogs. After 1 week, the grafts were harvested, vascular rings were cut from the midportion of the graft and suspended in organ chambers for isometric force measurements. Dose-response curves to various vasoactive compounds were determined and compared with those of nongrafted saphenous veins and carotid arteries. Results: Grafted vessels demonstrated a leftward shift of the dose-response curves in response to phenylephrine, histamine, and serotonin, but not to azepexole (BHT-933). Maximal contraction in response to all agents tested was also significantly decreased in grafted veins. Conclusions: Grafted saphenous veins have enhanced vascular reactivity 1 week after surgery. This enhanced vascular reactivity may contribute to early failure of venous grafts.