A Computational Study on Renal Artery Anatomy in Patients Treated with Fenestrated or Branched Endovascular Aneurysm Repair.

(1) Background: Renal artery occlusion after F/B EVAR for abdominal aortic aneurysm is a serious complication that may require re-intervention, and understanding the hemodynamic mechanisms by which it occurs is essential to optimize the surgical procedure. (2) Methods: We used computational fluid dynamics (CFD) to analyze the impact of various parameters on blood flow. Theoretical vascular models were constructed based on the common dimensions and angles of aortic stents and branch arteries in clinical practice. Actual case models were constructed from CT image data of six patients treated with F/B-EVAR. Data were collected for analysis after simulation and calculation by FLUENT software. (3) Results: Theoretical model simulations showed that a larger tilt angle of the branch stent, smaller branch entry depth, and larger branch stent diameter were beneficial for blood flow. In the case models, a significant difference in the tilt angle of the renal artery stents was observed between the high- and low-flow groups, while the differences in entry depth and branch stent diameter were not significant. Occluded renal arteries had lower WSS values than patent ones. (4) Conclusions: This study offers valuable guidance for optimizing stent placement in F/B EVAR to mitigate renal artery occlusion risk.