Mechanical behavior of a vein pouch saccular aneurysm model

The response of an intracranial saccular aneurysm to applied loads, whether blood pressure or endovascular intervention, depends on both the geometry and material properties of the lesion. Yet, in the development of animal models of these lesions little attention has been given to the evaluation of their mechanical behavior. Our goal was to compare the multiaxial mechanical behavior of a canine vein pouch model to published data on veins and human aneurysms. Nine vein pouches were created surgically in six mongrel dogs by anastomosing a 2 cm segment of the external jugular vein to the common carotid artery in an end-to-side fashion. The lesions were harvested one week post-surgery and subjected to cyclic inflation tests using a custom system. Pressure-regional strain data revealed that vein pouch aneurysms are very extensible for pressures up to 30 mmHg, especially in the axial direction, but stiff thereafter. None of the lesions ruptured in vivo or during inflation tests. Based on these data, we conclude that the overall behavior of canine vein pouch lesions, at one week post-surgery, did not mimic well that of human aneurysms. Thus, there is a need to pursue modifications or other models for the purposes of clinically relevant studies of lesion growth, rupture, and treatment.