Shear layer dynamics in aortic dissection: effect of flow pulsatility

Aortic dissection, kin to aneurysms, is an uncommon disease that involves weakening and partial tearing of the intimal layer lining the interior wall of the aorta. Delimitation of the layer along the vessel results in an inter-layer space that can fill with blood to form a parallel blood conduit known as the false lumen. Blood is supplied to the false lumen by an entry tear, while a re-entry tear downstream allows the two blood streams to merge back as one stream. Steady flow visualization in-vitro revealed a shear layer developing in the merger region and rolling up into a distinct vortex street [Salameh et al., CVET J. 2019]. The current study investigates the effect of using a more clinically relevant pulsatile flow on the shear layer development, and the possibility of the vortex shedding locking phase with the heartbeat. PIV measurements show that the flow is fundamentally altered including the basic shear layer characteristics. The results are consistent with recent clinical observations in patient cohorts which emphasized the importance of good hemodynamic understanding for improved management of patient outcomes and survival. Discussion will be provided on the clinical relevance of the results, and on future research directions including dissection-specific acoustic murmurs and their relation to the underlying disease hemodynamics.