The shear stess profile of the pivotal fenestrated endograft at the level of the renal branches: A computational study for complex aortic aneurysms.

Purpose: This study investigated the impact of the variant angulations on the values and distribution of wall shear stress on the renal branches and the mating vessels of a pivotal fenestrated design.

Methods: An idealized endograft model of two renal branches was computationally reconstructed with variable angulations of the left renal branch. These ranged from the 1:30' to 3:30' o'clock position, corresponding from 45° to 105° with increments of 15°. A fluid-structure-interaction analysis was performed to estimate the wall shear stress.

Results: The proximal part of the renal branch preserved quite constant wall shear stress. The transition zone between its distal end and the renal artery showed the highest values compared to the proximal and middle segments, ranging from 8.9 to 12.4 Pa. The lowest stress values presented at 90° whereas the highest at 45°. The post-mating arterial segment showed constantly low stress values regardless of the pivotal branch angle (6.3 to 6.6 Pa). The 45° configuration showed a distribution of the highest stress posteriorly whereas the 105°-angulation anteriorly.

Conclusions: The variant horizontal branch orientation influences the wall shear stress distribution across its length and affects its values only at its transition with the mating vessel. These findings and their potential association with adverse effects deserve further clinical validation.