Flow Velocity and Turbulence in the Transverse Aorta of a Proximally Directed Aortic Cannula: Hydrodynamic Study in a Transparent Model

Abstract

The objective of this study was to visualize and characterize the effect of cannula tip direction on flow within transverse aortic arch. A hydrodynamic analysis of the Dispersion arterial cannula (Edwards Lifescience LLC, Irvine, CA) was performed using particle image velocimetry in glass perfusion models of healthy and aneurysmal aortic arches. Flow velocity, streamline, distribution of magnitude of the strain rate tensor (function of shear stress), and degree of flow turbulence were comparatively analyzed for cannula tip directed toward the aortic arch (standard direction) and toward the aortic root (root direction). Standard direction cannulation in the model of the healthy aorta showed the flow velocity in the transverse aortic arch was rapid, the streamlines were nonlinear, and the magnitude of the strain rate tensor was high along aortic curvatures. Conversely, directing the cannula tip toward the aortic root generated slower and less turbulent flow in the transverse aortic arch despite high velocity and turbulence and nonlinear streamlines in the ascending aorta. In the aneurysmal aortic arch model, the flow velocity was more rapid in the area where aortic arch vessels originated, and a reversely directed vortex was observed between the aneurysm and the origination of the arch vessels. In the root direction model, the flow velocity distribution was slower than that in the standard direction. Directing the cannula tip of the Dispersion cannula toward the aortic root generated slower and less turbulent flow in the transverse arch of the glass models of both healthy and aneurysmal aortic arches.