Systolic fluid–structure interaction model of the congenitally bicuspid aortic valve: assessment of modelling requirements

Abstract

A transient fluid–structure interaction (FSI) model of a congenitally bicuspid aortic valve has been developed which allows simultaneous calculation of fluid flow and structural deformation. The valve is modelled during the systolic phase (the stage when blood pressure is elevated within the heart to pump blood to the body). The geometry was simplified to represent the bicuspid aortic valve in two dimensions. A congenital bicuspid valve is compared within the aortic root only and within the aortic arch. Symmetric and asymmetric cusps were simulated, along with differences in mechanical properties. A moving arbitrary Lagrange–Euler mesh was used to allow FSI. The FSI model requires blood flow to induce valve opening and induced strains in the region of 10%. It was determined that bicuspid aortic valve simulations required the inclusion of the ascending aorta and aortic arch. The flow patterns developed were sensitive to cusp asymmetry and differences in mechanical properties. Stiffening of the valve amplified peak velocities, and recirculation which developed in the ascending aorta. Model predictions demonstrate the need to take into account the category, including any existing cusp asymmetry, of a congenital bicuspid aortic valve when simulating its fluid flow and mechanics.

Keywords::

• bicuspid aortic valve
• congenital malformation
• fluid–structure interaction
• multi-physics modelling

Acknowledgements

The authors thank Duncan E.T. Shepherd and David W.L. Hukins for useful discussion and comments on the manuscript.

Additional information

Funding

This work was supported by the Nuffield Foundation through a summer bursary awarded to MYSK [URB/39926]. The research leading to these results has received funding from the [European Community's] Seventh Framework Programme [FP7/2007-2013] under a Marie Curie Intra-European Fellowship for Career Development [grant agreement number 252278], awarded to DME.