Thorac Cardiovasc Surg 2014; 62 - SC122
DOI: 10.1055/s-0034-1367383

Dispersive aortic cannulas reduce aortic wall shear stress affecting atherosclerotic plaque embolisation

A. Assmann 1, F. Gül 2, A.C. Benim 2, F. Joos 3, P. Akhyari 1, A. Lichtenberg 1
  • 1Heinrich Heine University, Medical Faculty, Department of Cardiovascular Surgery, Duesseldorf, Germany
  • 2Duesseldorf University of Applied Sciences, CFD Lab, Department of Mechanical and Process Engineering, Duesseldorf, Germany
  • 3Helmut Schmidt University, Laboratory of Turbomachinery, Hamburg, Germany

Objectives: Neurologic complications during on-pump cardiovascular surgery are prevalently induced by mobilisation 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.

Methods: An idealized numerical model of the human aorta and its outlets was created, and straight as well as bent aortic cannulas with dispersive tips were inserted in the distal ascending aorta. Standard straight or bent cannulas served as controls. Using a validated computing method, simulations of pulsatile and non-pulsatile extracorporeal circulation were performed.

Results: Dispersive aortic cannulas reduced the maximum and average aortic wall shear stress values to approximately 50% as compared to control cannulas, while the difference of local values was even larger. Moreover, at pulsatile circulation, dispersive cannulas shortened the time period of high wall shear stress values. The turbulent kinetic energy was diminished by utilizing dispersive cannulas.

Conclusion: Dispersive aortic cannulas decrease aortic wall shear stress during extracorporeal circulation, and may therefore reduce the risk of endothelial damage and neurologic complications caused by atherosclerotic plaque mobilisation.