A NEW ANIMAL-MODEL FOR ABDOMINAL AORTIC-ANEURYSMS - INITIAL RESULTS USING A MULTIPLE-WIRE STENT

Objectives: The effect of a plain 48-wire self-expanding flexible sten t (Wallstent-Schneider (Europe) AG) on abdominal aortic aneurysms has been studied in a new animal model. Methods: Aneurysms were created by interposing fusiform segments of glutaraldehyde-tanned bovine interna l jugular vein into the infrarenal aortas of 12 Large White pigs. The first six pigs were assessed after 6 weeks by ultrasonography and arte riography; they were then sacrificed for pathological examination. End ovascular placement of the stents, 2 weeks after aneurysm creation, wa s performed under arteriographic control in the next six pigs. These p igs were assessed by ultrasonography and arteriography 6 weeks after s tenting they were their sacrificed for pathological examination. Resul ts: At 6 weeks the aneurysms in the first group were pulsatile with pa rtial endothelialisation and no mural thrombus. Placement of the stent in the second group was accomplished easily. Stenting resulted in an immediate reduction in wall pulsatility of all aneurysms and thrombosi s of the excluded aneurysm sac occurred in three cases. In the other t hree cases the pulse pressure in the sac was reduced. In all cases the re tons a significant reduction in maximum aneurysm diameter when meas ured 6 weeks after stenting. Conclusions: A pulsatile, non-thrombogeni c aortic aneurysm model approaching human dimensions has been successf ully developed for the study of endoprostheses prior to their clinical use. Endovascular placement of a plain, multiple-wire Wallstent was a ssociated with reductions in aneurysm pulsatility, pulse pressure with in the sac and maximum aneurysm diameter over the study period. Stenti ng was associated with thrombosis of the excluded aneurysm sac in 50% of cases.