Endovascular aneurysmal models at the external iliac artery of dogs

Introduction: Establishing an aneurysm model using simple and easy operative techniques is desirable to develop new endovascular treatment devices such as stent grafts. We developed an aneurysm model using the external iliac arteries (EIAs) of adult Beagles, a relatively large animal that we thought would be easy to handle, using simple and less complicated endovascular procedures. In addition, we evaluated the generated aneurysm model histologically and determined the factors that were necessary for creating more dilated aneurysms. Methods: Experimental animals consisted of 16 beagles (average weight, 14.0 kg). The animals were divided into four groups (S, E, B+S, and B+E). Eight Beagles were in the S and E groups, without balloon dilation. S group Beagles were injected with normal saline into the right EIA and served as a control group. Elastase was injected into the left EIA of the same Beagles (E group). Eight Beagles were in the B+S and B+E groups with balloon dilation. After balloon dilation, normal saline was injected into right EIA of the B+S group. Elastase was injected into the left EIA of the same Beagles (B+E). After 4 weeks, we measured the EIA diameter using abdominal ultrasound imaging from a body surface. Both sides of the EIA were harvested. We evaluated the dilation rate of the EIA diameter, and histologically, evaluated the disappearance of the internal elastic lamina, degeneration and disappearance of medial smooth muscle and the external elastic lamina, and neointimal thickening. Results: Inner diameters were dilated more in the B+E group vs the other groups. The B+E group internal elastic lamina had almost disappeared, with significantly more severe degeneration and disappearance of external elastic lamina. Conclusions: We developed a muscular artery aneurysm model using the EIA arteries of adult Beagles and a simple endovascular procedure. Histologically, internal and external elastic lamina degeneration was an important factor to create significantly dilated aneurysms in this muscular artery model.