Stable vortices within vein cuffs inhibit anastomotic myointimal hyperplasia?

Abstract

Interposition vein cuffs improve the patency of below-knee ePTFE arterial grafts, and there is evidence that they do so, at least in part, by modifying the distribution of myointimal hyperplasia (MIH) at the distal anastomosis. Alteration of local haemodynamics is one of the mechanisms which might be involved. The purpose of this study was to characterise the local haemodynamics within an interposition vein cuff. Flow patterns have been analysed in a laboratory model of cuffed anastomosis and compared with observations made in patients by cine intra-arterial digital subtraction angiography (IA DSA) and dynamic colour duplex scanning. In contrast to non-cuffed anastomoses in which the flow is predominantly laminar, cuffed anastomoses are associated with the formation of a coherent vortex. High frictional forces or shear stress exerted upon the arterial wall by the vortex could explain the beneficial effect of a cuff upon anastomotic MIH, in which case the optimal configuration of small vessel anastomoses would be that which most effectively promotes the formation of this type of vortex.