Analytical Side-to-Side Related Anastomotic Strategies and Artery Patching

Suture line stress concentration and intimal hyperplasia are related to the long-term complications of end-toside and side-to-side anastomosis. Several factors, such as hemodynamic effects, biological activities and the mechanical properties of the blood vessels, are identified to influence the problem. Yet, it is not completely clear which are the factors that influence most the long-term complications and in what specific way. This study aims to examine if elastic (compliance) mismatch increases the stress concentration and intimal thickening at the suture line. Better compliance may be obtained by using grafts with similar mechanical properties to the host artery or by anastomosis techniques that utilize vein patches and cuffs (Taylor-patch and Miller-cuff anastomosis). The anastomosis model used in this study is a circular cylindrical system consisting of two semi-cylinders, interconnected by two hinges. The internal blood pressure is applied on the arterial walls. The static and dynamic responses are analytically derived in terms of radial and tangential displacements, internal forces and strains of the two blood vessels and rotation of their cross-section. Results suggest that increased elastic mismatch between the artery and the graft may promote elevated intimal thickening due to large incompatible angles at the junction, whereas there is no correlation between elastic mismatch and elevated stress concentration at the suture line. Another interesting application of the present model is the patching of arteries as applied in carotid endarterectomy.