Structural and functional aspects of the human saphenous vein used as aorto-coronary graft in myocardial revascularization.

The human saphenous vein (HSV) is currently used as a graft in coronary rev ascularization as well as in some other vascular beds, namely those of the inferior limbs. Since a significant proportion of HSV grafts develop stenos is, many studies have focused on the factors that could promote graft failu re. This article reviews the results on structural and functional features that might be concurrent in the production of saphenous vein graft stenosis . The reactivity of HSV to several physiological agonists is analyzed, incl uding those derived from the endothelium with contractile or relaxing prope rties, since these are relevant inducers of graft spasm and/or modifiers of the expression of graft factors involved in either tissue growth or thromb otic-atherosclerotic processes. Mechanisms that regulate vascular smooth mu scle contractile state, in particular the activity of K+ channels of the pl asma membrane, are described.