Effects on Aortoiliac Fluid Dynamics After Endovascular Sealing of Abdominal Aneurysms

Vasc Endovascular Surg. 2018 Nov;52(8):621-628. doi: 10.1177/1538574418791059. Epub 2018 Jul 29.


Objectives:: To evaluate the effects on aortoiliac fluid dynamics after the implantation of an endograft based on endovascular aneurysm sealing (EVAS) versus endovascular aneurysm repair (EVAR) strategy.

Methods:: An adaptive geometrical deformable model was used for aortic lumen segmentation in 8 patients before and after the surgery. Abdominal aneurysms were treated with an endograft based on the EVAS system (Nellix, n = 4) and with a device based on an anatomical fixation technology (n = 4). Pressure, blood velocity, and wall shear stress (WSS) were estimated at different aortic regions using computational fluid dynamics methods. Physiologic inlet/outlet flow values at the abdominal aorta, the celiac trunk, and the mesenteric and the renal arteries were set. Pressure references were set at iliac arteries outlet.

Results:: Maximum aneurysm sizes were similar for both groups in the preoperative scans. The lumen area was lower after EVAR ( P < .05) and EVAS ( P < .01) compared to preoperative aortic lumen sizes. Pressure increase was higher in the proximal abdominal aorta after EVAS compared to EVAR (2.3 ± 0.3 mm Hg vs 0.9 ± 0.3 mm Hg, P < .001). Peak blood velocities inside the endografts were 3-fold higher for EVAS compared to EVAR (54 ± 5 cm/s vs 17 ± 4 cm/s, P < .01). Velocities at the iliac arteries also remained higher for EVAS (38 ± 4 cm/s vs 24 ± 4 cm/s, P < .05). Peak WSS at the iliac arteries remained higher for EVAS compared to EVAR group ( P < .05).

Conclusion:: The significant modification of the aortic bifurcation anatomy after EVAS alters aortoiliac fluid dynamics, showing a pressure impact at the renal arteries level and an acceleration of the blood velocity at the iliac region with a concomitant increase in peak WSS.

Keywords: Nellix endograft; abdominal aortic aneurysm; computational fluid dynamics; endovascular repair; geometric deformable models; sac anchoring prosthesis.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Aorta, Abdominal / diagnostic imaging
  • Aorta, Abdominal / physiopathology
  • Aorta, Abdominal / surgery*
  • Aortic Aneurysm, Abdominal / diagnostic imaging
  • Aortic Aneurysm, Abdominal / physiopathology
  • Aortic Aneurysm, Abdominal / surgery*
  • Arterial Pressure
  • Blood Flow Velocity
  • Blood Vessel Prosthesis
  • Blood Vessel Prosthesis Implantation* / adverse effects
  • Blood Vessel Prosthesis Implantation* / instrumentation
  • Endovascular Procedures* / adverse effects
  • Endovascular Procedures* / instrumentation
  • Hemodynamics*
  • Humans
  • Hydrodynamics
  • Iliac Artery / diagnostic imaging
  • Iliac Artery / physiopathology
  • Iliac Artery / surgery*
  • Male
  • Models, Cardiovascular*
  • Patient-Specific Modeling*
  • Retrospective Studies
  • Stents
  • Treatment Outcome