title: Studying the flow dynamics in an aortic endograft with crossed-limbs.
abstract: OBJECTIVE
  To evaluate the flow phenomena within an aortic endograft with crossed-limbs, comparing to an endograft with the ordinary limb bifurcation.
  
  
  METHODS
  An endograft model with crossed-limbs was computationally reconstructed based on Computed Tomography patient-specific data, using commercially available software. Accordingly, its analogue model was reconstructed in the ordinary fashion (ordinary bifurcation). Computational fluid dynamics analysis was performed to determine and compare the flow fields, velocity profiles, pressure and shear stress distribution throughout the different parts of both endograft configurations, in different phases of the cardiac cycle.
  
  
  RESULTS
  The flow patterns between the "Ballerina" and the classic endograft were similar, with flow disturbance near the inlet zone at late diastole and smooth flow patterns during the systolic phase. Both configurations presented similar pressure distribution patterns throughout the cardiac cycle. The highest and lowest pressures were demonstrated in the inlet-main body area and the iliac limbs, respectively. Marked differences were observed in the velocity profiles of the proximal limb segments between the two configurations, mostly in the peak- and end-systolic phase. The regions of lower velocities correlated well to low shear values. Differences in the shear stress distribution were noted between the two configurations in the systolic and, predominantly, in the diastolic phase.
  
  
  CONCLUSIONS
  There are differences in the velocity profiles and shear distribution between the limbs of the two endograft configurations. The pathophysiologic implication of our findings and their possible association with clinical events, such as thrombus apposition, deserves further investigation.
authors.affiliation: 1 Department of Vascular Surgery, Democritus Medical School, University Hospital of Alexandroupolis, Alexandroupolis - Greece.
authors.forename: Efstratios
authors.initials: E
authors.lastname: Georgakarakos
authors.forename: Antonios
authors.initials: A
authors.lastname: Xenakis
authors.forename: Christos
authors.initials: C
authors.lastname: Manopoulos
authors.forename: George S
authors.initials: GS
authors.lastname: Georgiadis
authors.forename: Christos
authors.initials: C
authors.lastname: Argyriou
authors.forename: Sokrates
authors.initials: S
authors.lastname: Tsangaris
authors.forename: Miltos K
authors.initials: MK
authors.lastname: Lazarides
mesh_terms: D001014:Aortic Aneurysm / Q000000981:diagnostic imaging / Q000601:surgery*; D001783:Blood Flow Velocity; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000379:methods*; D003198:Computer Simulation; D057510:Endovascular Procedures; D006439:Hemodynamics; D018056:Hemorheology; D006801:Humans; D008955:Models, Cardiovascular; D011474:Prosthesis Design; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed