A new biomechanical approach to assessing the fragility of the internal elastic lamina of the arterial wall.

Patterns of tearing of the internal elastic lamina induced by controlled tensile extension of the arterial wall in the axial direction are similar morphologically to those induced in vivo in the anastomosed arteries of experimental arteriovenous fistulae. The mural response is modelled with a simple bi-layer analogue and it is shown that the internal elastic lamina exhibits a greater degree of strain-limiting deformation behavior in the axial direction than the medial and adventitial layers. Application of laminate theory indicates that the frequency of intimal tearing along the vessel length is directly related to the failure strength of the intimal layer.