Vascular heterografts for hemodyalisis access: analysis of elastic and viscous matching factor between human and ovine vessels

Long-term vascular accesses are usu- ally performed in patients submitted to renal re- placement therapy using autologous vessels. When arterio-venous fistula creation is impossible, animal conduits have been used in order to obtain high patency rates. Bovine vessel heterograft has been introduced as a substitute for the construction of arterio-venous fistulas. However, when experimental research of graft failure is focused to vascular wall properties, the ovine model is one of the more fre- quently utilized instead of the study of bovine ves- sels. Biomechanical vessel wall properties study is very important, since the viscoelastic mismatch among the fistulae conduits has been pointed out as a determinant of intimal hyperplasia, a cause of access dysfunction. In this work we have analyzed viscoelastic prop- erties of arteries and veins harvested from human donors in brain death condition and healthy sheep. The elastic mismatch calculus revealed that the hu- man brachial artery and the ovine jugular veins ex- hibit the best coupling accompanied by an optimal viscous matching.