A coupled fluid-structure finite element model of the aortic valve and root.

BACKGROUND AND AIM OF THE STUDY: The study aim was to develop a three-dimensional coupled fluid-structure finite element model of the aortic valve and root. This model extends previous purely structural finite element models, and represents a significant step toward realistic simulation of the complex interactions among tissue material properties and valvular function.

METHODS: The aortic root and valve geometry were extracted from magnetic resonance images and imported into the LS-Dyna explicit finite element package. Leaflet and root tissue were modeled with elastic material properties, and blood was modeled as a Newtonian liquid. A dynamic, fully unsteady analysis was performed in which blood flow through the valve was computed along with the motion of the leaflets and root in response to standard physiologic pressure wave profiles.

RESULTS: The opening and closing of the aortic valve under physiological loading conditions was successfully simulated, and feasibility of the model illustrated. The motion of the simulated leaflets was consistent with that seen in intact hearts. Analysis of fluid flow patterns revealed eddy structures in the sinus regions and flow into the coronary circulation.

CONCLUSION: The addition of blood flow to structural models of the aortic valve and root is a significant advance in modeling, and allows a closer simulation of valvular function. The model will be used to further assess normal and abnormal physiology as well as the effects of surgical intervention.