The Investigation of Flow Separation Downstream of a Slotted Tube Stent in the Presence of a Pulsatile Flow Environment

Stent strut configuration has been found to alter local fluid flow and wall shear stress (WSS) patterns that can promote intimal hyperplasia. To quantify these alterations, we used particle image velocimetry (PIV) to investigate local fluid dynamics distal to a deployed stent within an acrylic tube. A blood analogue mixture of glycerol and water was pumped through a flow loop in both steady and pulsatile conditions. Steady and pulsatile velocity profiles and near WSS (NWSS) predicted by PIV were in good agreement with the Poiseuille and Womersley estimations. Introduction of a Palmaz balloon expanded slotted tube stent increased centerline velocities between 6.9% and 9% and decreased NWSS distal from the stent outlet by > 40%. Peak normalized vorticity was similar between non-stented and stented flows, although spatial coverage of higher vorticity was increased upon stent introduction. Future work will incorporate Echo PIV to complement PIV findings on how strut configuration affects flow dynamics.