Effect of blood flow rate on subendothelial proliferation in venous autografts used as arterial substitutes.

The effect of augmented and reduced blood flow rates through autogenous vein grafts (AVG) on the histological characteristics of veins used for arterial substitutes was studied in 22 dogs. In each animal autogenous jugular veins were implanted as conduits to replace excised segments of both iliac arteries. In one group (control) blood flow through the AVG conduits was not modified, but in the remaining animals blood flow rate was either augmented by a distal femoral arteriovenous fistula or reduced by a distal arterial stenosis. In the control group in which there was no modification of blood flow, subendothelial proliferative lesions (SEPL) were found in the vein graft, and typical SEPL were found at each anastomosis. However, in those animals in which blood flow was reduced by an average of 44% through the graft, SEPL were more numerous throughout the length of the vein graft, and the anastomotic SEPL were more prominent. In contrast, those animals in which a unilateral distal arteriovenous fistula augmented blood flow through the AVG (average 6.7-fold increase), no SEPL were detected along the length of the graft. Although SEPL were present at the suture lines, the lesions were much less prominent. These findings suggest that the magnitude and distribution of SEPL in AVG are determined, in part, by the rate of blood flow through the graft.