Purpose: To develop canine aneurysm models that can reproduce type II endoleaks after endovascular aneurysm repair (EVAR) with stent-grafts.
Materials and methods: A fusiform infrarenal abdominal aortic aneurysm model (AAA) was surgically created with a jugular vein patch, while preserving collateral vessels (n = 3). To allow comparative studies within the same animal, a bilateral iliac aneurysm model was also constructed with venous patches and surgical re-implantation of the sacroiliac trunk (n = 3). Stent-grafts were implanted by femoral approach at least 2 months later in both aortic and iliac models. Follow-up imaging was performed by Doppler ultrasound (US) and angiography until animals were killed 3 months after EVAR.
Results: Angiography revealed immediate type II leaks in all cases. Leaks were still present at autopsy 3 months after EVAR in all cases, and were revealed at pre-death angiography in all but one case. At autopsy, leaks were characterized by the presence of large endothelialized channels that formed within the thrombus between the stent-graft and the aneurysmal wall.
Conclusion: As shown in this pilot study, persistent type II leaks after EVAR can be reproduced in aortic and iliac animal models. The iliac model can be created bilaterally in the same animal, thus allowing for comparative evaluation of different therapies. These models could be used to better understand the mechanisms of endoleak, and to assess future developments aimed to improve the outcomes after EVAR.