title: Dispersive aortic cannulas reduce aortic wall shear stress affecting atherosclerotic plaque embolization.
abstract: Neurologic complications during on-pump cardiovascular surgery are often induced by mobilization of atherosclerotic plaques, which is directly related to enhanced wall shear stress. In the present study, we numerically evaluated the impact of dispersive aortic cannulas on aortic blood flow characteristics, with special regard to the resulting wall shear stress profiles. An idealized numerical model of the human aorta and its branches was created and used to model straight as well as bent dispersive aortic cannulas with meshlike tips inserted in the distal ascending aorta. Standard cannulas with straight beveled or bent tips served as controls. Using a recently optimized computing method, simulations of pulsatile and nonpulsatile extracorporeal circulation were performed. Dispersive aortic cannulas reduced the maximum and average aortic wall shear stress values to approximately 50% of those with control cannulas, while the difference in local values was even larger. Moreover, under pulsatile circulation, dispersive cannulas shortened the time period during which wall shear stress values were increased. The turbulent kinetic energy was also diminished by utilizing dispersive cannulas, reducing the risk of hemolysis. In summary, dispersive aortic cannulas decrease aortic wall shear stress and turbulence during extracorporeal circulation and may therefore reduce the risk of endothelial and blood cell damage as well as that of neurologic complications caused by atherosclerotic plaque mobilization.
authors.affiliation: Research Group for Experimental Surgery, Department of Cardiovascular Surgery, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany; Department of Medicine, Center for Biomedical Engineering, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Assmann
authors.forename: Fethi
authors.initials: F
authors.lastname: Gül
authors.forename: Ali Cemal
authors.initials: AC
authors.lastname: Benim
authors.forename: Franz
authors.initials: F
authors.lastname: Joos
authors.forename: Payam
authors.initials: P
authors.lastname: Akhyari
authors.forename: Artur
authors.initials: A
authors.lastname: Lichtenberg
mesh_terms: D001011:Aorta / Q000503:physiopathology*; D001783:Blood Flow Velocity; D006328:Cardiac Catheterization / Q000295:instrumentation / Q000379:methods*; D005112:Extracorporeal Circulation / Q000009:adverse effects* / Q000379:methods; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008955:Models, Cardiovascular; D058226:Plaque, Atherosclerotic / Q000503:physiopathology / Q000601:surgery*; D011673:Pulsatile Flow; D012016:Reference Values; D015203:Reproducibility of Results; D033081:Shear Strength / Q000502:physiology*; D013314:Stress, Mechanical
keywords: Aortic blood flow; Aortic cannula; Computational fluid dynamics; Extracorporeal circulation; Plaque embolization; Wall shear stress