SELF-EXPANDABLE MACROPOROUS NITINOL STENTS FOR TRANSFEMORAL EXCLUSIONOF AORTIC-ANEURYSMS IN DOGS - PRELIMINARY-RESULTS

This experimental study evaluated the feasibility of excluding artific ially created aortic aneurysms in dogs with transfemorally inserted ni tinol stents, serving as intraluminal bypass. Infrarenal aortic aneury sms were created in eleven dogs (28-35 kg) by end-to-end anastomosis o f sacciform conduits. Single and double wire-knitted, macroporous, sup erelastic, self-expanding nitinol stents without any additional wrappi ng or in-between fabrics served as endovascular grafts. The pore size of the double-knitted stents was less than 0.7 mm2. Angiography follow ing stent placement showed immediate exclusion of the aneurysms for th e double-knitted stents. For the single-knitted stents (2 cases), part ial exclusion was achieved only after considerable delay. CT studies i n the dogs with the double-knitted stents revealed patency of the graf ts after 3 to 5 weeks with the aneurysms totally thrombosed. So far gr oss pathology of 1 dog at 24 h and 1 at 12 months revealed patency of the stents. At 12 months histopathology showed a neointima covering th e inner stent surface with the aneurysm filled by an organized thrombu s. It is concluded, that an ''open'' stent with a tight meshwork appea rs to be a suitable device to instantly exclude artificial aneurysms o f the canine aorta.