Abdominal aortic aneurysms in sheep: prevention of rupture with endoluminal stent-grafts

PURPOSE: The authors evaluated the ability of an aortic balloon-expandable endovascular stent-graft to prevent rupture in a model of spontaneously rupturing abdominal aortic aneurysms in sheep. MATERIALS AND METHODS: Aneurysms were created in 16 sheep by inserting a 60 x 18-mm segment of the left internal jugular vein, end-to-end anastomosed, to the sectioned infrarenal abdominal aorta. The sheep were randomly assigned into two groups; eight animals underwent endovascular implantation of an 80 x 12-mm balloon expandable stent-graft (group A), and eight were only followed up (group B). RESULTS: In group B, seven of eight animals had died of aneurysmal rupture by 3 months. In group A, six of the eight aortic aneurysms were immediately excluded, and six animals were alive at 3 months without rupture. The 3-month survival rate was 100% in group A and 12% in group B (P = .0023). Macro- and microscopic analysis of the section of the aorta in which the stent-graft had been placed revealed rapid retraction of the aneurysmal sac. CONCLUSION: Placement of an endovascular stent-graft induced regression of a branchless aneurysm and prevented rupture.