The Heart Valve Society

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Under What Conditions Do We Find Vortical Flow in the Sinus of Valsalva?
David Hasler1, Bernhard Vennemann2, Stefan Stortecky3, Thomas Pilgrim3, Dominik Obrist1.
1ARTORG Center, University of Bern, Bern, Switzerland, 2Institute of Fluid Dynamics, ETH Zürich, Zürich, Switzerland, 3Department of Cardiology, Bern University Hospital, University of Bern, Bern, Switzerland.

OBJECTIVE:The flow in the sinus of Valsalva has gained significant interest in recent years. There appears to be a consensus regarding the existence of one or multiple aortic sinus vortices. Aortic valve hemodynamics seem to benefit from such vortices: better washout behind valve leaflets, increased geometric orifice area and smoother valve closure. Given the wide range of different aortic root morphologies and valve designs and the complex nature of the flow (pulsatile, turbulent, three-dimensional) it remains unclear whether these vortices always exist and how their shape and strength is affected by the given conditions. This study investigates the three-dimensional flow in the sinus of Valsalva (sinus flow) in function of aortic root morphology.
METHODS:A bio-prosthetic heart valve (Edwards Intuity Elite 21 mm) was integrated in a custom-built pulse duplicator. Tomographic particle image velocimetry was used to obtain phase-looked measurements of the 3D velocity fields in the vicinity of the valve including the sinus portions. The measurements were conducted in transparent silicone phantoms of the ascending aorta. Aortic roots of various shape and distensibility were tested with different flow profiles.
RESULTS:Sinus flow velocities were on the order of 5-20% of the bulk flow velocity through the valve orifice. In contrast to the classically described regular sinus vortex, we observed dominant vortical rotation in the opposite direction, complex unsteady three-dimensional flow structures, configurations with dominant circumferential flow components and large recirculation regions which transport fluid from the ascending aorta back into the sinus.
CONCLUSIONS:The flow in the sinus of Valsalva was found to depend on the morphology of the aortic root and exhibited continuous or intermittent and strong or weak motion. The classical concept of a single robust large vortex in the sinus portion should be critically revisited - in particular for patient-specific aortic roots.


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