Structural and functional smooth muscle injury after surgical preparation of reversed and non-reversed (<i>in situ</i>) saphenous vein bypass grafts

Abstract

Intimal hyperplasia and isolated stenoses are major factors in determining the long-term patency of reversed and in situ vein grafts. Surgical handling causes functional endothelial damage in reversed vein grafts but the effects of valvulotome use are unknown. Saphenous vein samples were taken after minimal dissection (control), distension with saline, or after the passage of a valvulotome. Rectangular strips of vein were mounted in an organ bath and cumulative noradrenaline (10(-8)-10(-5) M) dose contraction curves were performed. Compared with controls there was a significant reduction in the contractile response of both the distended and valvulotome-prepared veins (P less than 0.05). Histological studies revealed partial endothelial cell loss in the distended group and total endothelial cell loss with patchy necrosis of the smooth muscle in the valvulotome group. These results suggest that the current use of a valvulotome not only renders the valves incompetent but also seriously damages the function of the smooth muscle layer.