Can neck size in elastase-induced aneurysms be controlled? A retrospective study.

Background and Purpose: Reproducible animal models with appropriate neck size are crucial for preclinical assessment of aneurysm therapies. Our purpose was to determine whether the neck size of elastase-induced aneurysms could be controlled by adjusting the position of the temporary occlusion balloon.
Methods: Seventy-two elastase-induced aneurysms in rabbits were retrospectively analyzed. Three groups (group 1, n = 35; group 2, n = 32; group 3, n = 5) were defined according to different balloon position (lowest, intermediate, and highest, respectively) related to the origin of right common carotid artery (CCA). Aneurysm sizes in different groups were measured and compared; parent artery dilation was assessed as present or absent. The Wilcoxon rank sum test, the Fisher exact test, and the chi(2) test were used for statistics process.
Results: The mean aneurysm neck diameter in group 1 was significantly wider than that in group 2 (P = .0001). The proportion of wide-necked (diameter of neck >4 mm) aneurysms in group 1 was significantly higher than that in group 2 (P = .0011). The mean dome/neck ratio in group 1 was smaller than that of group 2 (P = .0031). Aneurysm width and height and the frequency of parent artery dilation were not different in groups 1 and 2 (P = .43, P = .10, and P = .25). No aneurysms formed in group 3.
Conclusion: The neck size of elastase-induced aneurysms can be controlled by adjusting the position of the inflated balloon, with balloon positioning that bridges from the CCA to the subclavian/brachiocephalic arteries yielding narrow-necked aneurysms.