Endovascular AAA exclusion: Will stents with hooks and barbs prevent stent-graft migration?

Purpose: To investigate if stents with hooks and barbs will improve stent-g raft fixation in the abdominal aorta. Methods: Sixteen- to 24-mm-diameter Dacron grafts were deployed inside cada veric aortas. The grafts were anchored by stents as in endovascular abdomin al aortic aneurysm repair. One hundred thirty-seven stent-graft deployments were carried out with modified self-expanding Z-stents with (A) no hooks a nd barbs (n = 75), (B) 4 5-mm-long hooks and barbs (n = 39), (C) 8 10-mm-lo ng, strengthened hooks and barbs (n = 19), or (D) hooks only (n = 4). Incre asing longitudinal traction was applied to determine the displacement force needed to extract the stent-g rafts. The radial force of the stents was me asured a nd correlated to the displacement force. Results: The median (interquartile range) displacement force needed to extr act grafts anchored by stent A was 2.5 N (2.0 to 3.4), stent B 7.8 N (7.4 t o 10.8), and stent C 22.5 N (17.1 to 27.9), p < 0.001. Both hooks and barbs added anchoring strength. During traction, the weaker barbs were distorted or caused intimal tears. The stronger barbs engaged the entire aortic wall . The radial force of the stents had no impact on fixation, while aortic ca lcification and graft oversizing had marginal effects. Conclusions: Stent barbs and hooks increased the fixation of stent-grafts t enfold, while the radial force of stents had no impact. These data may prov e important in future endograft development to prevent stent-graft migratio n after aneurysm exclusion.