Compliance: a continuing problem with vascular grafts.

Compliance mismatch between host artery and synthetic vascular substitutes has rarely been mentioned in the literature as a possible cause of suture line disruption and damage to endothelial and platelet cells. In this paper we have attempted to elucidate on how compliance mismatch can predispose: (1) anastomotic rupture, (2) flow induced shear stres and, (3) reduced distal perfusion. We have concluded that in order to minimize all three of these factors the compliance of the vascular substitute should be equivalent to the host artery to which it is to be anastomosed. It appears that the factor which is most seriously affected by the compliance mismatch is the flow regimen in that flow separation regions forms at the distal anastomosis. Shear stresses, due to eddies in these regions of flow separation, are of significant magnitude to destroy endothelial cells lining the vascular wall and platelets existing in the boundary layer.