The Effect of the Curvature of the Abdominal Aorta Aneurysm on the Migration Forces Acting on a Stent Graft

Background: Abdominal Aorta Aneurysm (AAA) is an irreversible dealation of the artery walls which is defined by growth of 50% of the artery diameter. Endovascular aneurysm repair (EVAR) stent grafts (SGs) offer an alternative treatment for conventional open vascular surgery. The SG restore normal blood flow regime to the artery, but in 1% of these cases, there is a stent migration problem in the connection between the top part of the SG to the artery.

The aim of this study is to find the relation between the magnitude of the drag forces and aorta curvature,

Methods: Geometry structures of AAA of patients specific were reconstructed from CT. For each patient, a stent graft was inserted, tailored to his specific geometry. Computational fluid dynamics (CFD) simulations of pulsatile blood flow during the cardiac cycle, were employed, and drag forces were calculated.

Results: The values of the drag forces which were obtained from cases of three specific patients were 6.25-9.25 N. These results are corresponding with the values shown in the literature.

Conclusion: As the aneurysm diameter and the healthy artery inlet diameter become wider, the drag force increased linearly, however it`s not clear enough if the morphology of the aneurysm or the healthy artery influence the drag force in a way that it may cause migration to the stent graft.