Canine Model of Abdominal Aortic Aneurysm Treated by Endovascular Graft Implantation

The purpose of this study was to monitor the effects of endovascular graft implantation on a canine model of aortic aneurysm. Aneurysms were created in 10 dogs by fascial patch angioplasty of the infrarenal aorta. In five dogs, aneurysm creation was immediately followed by insertion of an endovascular graft. Central aortic and aneurysm sac pressures were then measured by needle puncture. The remaining five dogs were left untreated, as controls. Angiography was performed after aneurysm creation, after endovascular graft implantation, and at 1 month and 3 months. Following insertion of an endovascular graft, mean (s.d.) systolic pressure was lower in the aneurysm sac (82.9 (20.20) mmHg) than in the adjacent aorta (113.4 (25.9) mmHg; P < 0.002) in all the treatment group. The effects on diastolic pressure and mean pressure were less pronounced. Aneurysm size was increased in all controls (25.2 (9.55)%) and decreased in all of the treated group (22.5 (11.7)%: P < 0.001). In conclusion this model of aortic aneurysm has two important characteristics; it has multiple collateral branches, and it grows. Insertion of an endovascular graft was associated with a reduction in aneurysm sac pressure, reduced aneurysm growth, and fibrosis of the space between the aneurysm sac and the graft.