title: The Relationship Between Pulsatile Flow Impingement and Intraluminal Thrombus Deposition in Abdominal Aortic Aneurysms.
abstract: Direct numerical simulations were performed on four patient-specific abdominal aortic aneurysm (AAA) geometries and the resulting pulsatile blood flow dynamics were compared to aneurysm shape and correlated with intraluminal thrombus (ILT) deposition. For three of the cases, turbulent vortex structures impinged/sheared along the anterior wall and along the posterior wall a zone of recirculating blood formed. Within the impingement region the AAA wall was devoid of ILT and remote to this region there was an accumulation of ILT. The high wall shear stress (WSS) caused by the impact of vortexes is thought to prevent the attachment of ILT. WSS from impingement is comparable to peak-systolic WSS in a normal-sized aorta and therefore may not damage the wall. Expansion occurred to a greater extent in the direction of jet impingement and the wall-normal force from the continuous impact of vortexes may contribute to expansion. It was shown that the impingement region has low oscillatory shear index (OSI) and recirculation zones can have either low or high OSI. No correlation could be identified between OSI and ILT deposition since different flow dynamics can have similar OSI values.
authors.affiliation: Department of Mechanical Engineering, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: Richard J
authors.identifier: 0000-0002-8428-4981
authors.initials: RJ
authors.lastname: Lozowy
authors.affiliation: Department of Mechanical Engineering, University of Manitoba, Winnipeg, MB, Canada. david.kuhn@umanitoba.ca.
authors.forename: David C S
authors.initials: DC
authors.lastname: Kuhn
authors.affiliation: Department of Surgery, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: Annie A
authors.initials: AA
authors.lastname: Ducas
authors.affiliation: Department of Surgery, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: April J
authors.initials: AJ
authors.lastname: Boyd
mesh_terms: D001012:Aorta, Abdominal / Q000503:physiopathology; D017544:Aortic Aneurysm, Abdominal / Q000503:physiopathology*; D001783:Blood Flow Velocity; D003198:Computer Simulation; D006439:Hemodynamics; D006801:Humans; D008955:Models, Cardiovascular; D011673:Pulsatile Flow; D013314:Stress, Mechanical; D013927:Thrombosis / Q000503:physiopathology*
keywords: Abdominal aortic aneurysm; Intraluminal thrombus; Oscillating wall shear stress; Pulsatile flow