title: Hemodynamic analysis of edge stenosis in peripheral artery stent grafts.
abstract: OBJECTIVE
  The purpose of this study was to characterize the hemodynamics of peripheral artery stent grafts to guide intelligent stent redesign.
  
  
  METHODS
  Two surgically explanted porcine arteries were mounted in an ex vivo system with subsequent deployment of an Xpert self-expanding nitinol stent or Viabahn stent graft. The arteries were casted with radiopaque resin, and the cast then scanned using micro-computed tomography at 8μm isotropic voxel resolution. The arterial lumen was segmented and a computational mesh grid surface generated. Computational fluid dynamics (CFD) analysis was subsequently performed using COMSOL Multiphysics 5.1.
  
  
  RESULTS
  CFD analysis demonstrated low endothelial shear stress (ESS) involving 9.4 and 63.6% surface area of the central stent graft and bare metal stent, respectively. Recirculation zones were identified adjacent to the bare metal stent struts, while none were identified in the central stent graft. However, the stent graft demonstrated malapposition of the proximal stent graft edge with low velocity flow between the PTFE lining and arterial wall, which was associated with longitudinally and radially oriented recirculation zones and low ESS.
  
  
  CONCLUSIONS
  Computational hemodynamic analysis demonstrates that peripheral artery stent grafts have a superior central hemodynamic profile compared to bare metal stents. Stents grafts, however, suffer from malapposition at the proximal stent edge which is likely a major contributor to edge stenosis.
authors.affiliation: Division of Interventional Radiology, Department of Radiology, UCLA Medical Center, 757 Westwood Plaza, Suite 1638, 90095 Los Angeles, CA, USA. Electronic address: ramsey.hakim@gmail.com.
authors.forename: R
authors.initials: R
authors.lastname: Al-Hakim
authors.affiliation: Division of Interventional Radiology, Department of Radiology, UCLA Medical Center, 757 Westwood Plaza, Suite 1638, 90095 Los Angeles, CA, USA.
authors.forename: E W
authors.initials: EW
authors.lastname: Lee
authors.affiliation: Division of Interventional Radiology, Department of Radiology, UCLA Medical Center, 757 Westwood Plaza, Suite 1638, 90095 Los Angeles, CA, USA.
authors.forename: S T
authors.initials: ST
authors.lastname: Kee
authors.affiliation: Division of Interventional Radiology, Department of Radiology, UCLA Medical Center, 757 Westwood Plaza, Suite 1638, 90095 Los Angeles, CA, USA.
authors.forename: K
authors.initials: K
authors.lastname: Seals
authors.affiliation: Molecular Imaging Center, Keck School of Medicine of USC, 2250 Alcazar St, 90089 Los Angeles, CA, USA.
authors.forename: B
authors.initials: B
authors.lastname: Varghese
authors.affiliation: Division of Interventional Radiology, Department of Radiology, UCLA Medical Center, 757 Westwood Plaza, Suite 1638, 90095 Los Angeles, CA, USA.
authors.forename: A
authors.initials: A
authors.lastname: Chien
authors.affiliation: Division of Interventional Radiology, Department of Radiology, UCLA Medical Center, 757 Westwood Plaza, Suite 1638, 90095 Los Angeles, CA, USA.
authors.forename: M
authors.initials: M
authors.lastname: Quirk
authors.affiliation: Division of Interventional Radiology, Department of Radiology, UCLA Medical Center, 757 Westwood Plaza, Suite 1638, 90095 Los Angeles, CA, USA.
authors.forename: J
authors.initials: J
authors.lastname: McWilliams
mesh_terms: D000497:Alloys; D000818:Animals; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging*; D020099:Coated Materials, Biocompatible; D006439:Hemodynamics; D023421:Models, Animal; D011138:Polytetrafluoroethylene; D000069322:Self Expandable Metallic Stents; D015607:Stents; D013552:Swine; D055114:X-Ray Microtomography
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; C013616:nitinol; D011138:Polytetrafluoroethylene
keywords: Edge stenosis; Experimental studies; Hemodynamics; Peripheral artery; Stent graft