Abstract 13815: Predictions of Wall-shear Stress on the Bicuspid Aortic Valves Using Three-dimensional Fluid-structure Interaction Models
INTRODUCTION: The bicuspid aortic valve (BAV) is associated with a high prevalence of calcific aortic valve disease. Although abnormal hemodynamics has been proposed as potential pathogenic contributor, the native BAV hemodynamic stresses remain largely unknown. The objective of the present study was to characterize the regional wall shear stress (WSS) abnormalities on BAV leaflets using three-dimensional (3D) fluid-structure interaction (FSI) modeling.
METHODS: The normal tricuspid aortic valve (TAV) model consisted of the aortic root, the aortic sinus and three identical compliant leaflets. The type-0 BAV consists of two equally-sized leaflets and two sinuses with no visible raphe while the type-1 BAV is characterized by asymmetry between a normal leaflet and a larger fused leaflet. The fully coupled FSI simulations were run in ANSYS by imposing a physiologic transvalvular pressure at the inlet of the fluid domain. Local leaflet WSS was characterized in terms of temporal shear magnitude (TSM).
RESULTS: The TAV, type-0 BAV and type-1 BAV models successfully predicted leaflet and blood flow dynamics at a mean physiologic cardiac output of 4.2 L/min, 3.5 L/min and 3.2 L/min, respectively. The comparison of the flow in the three anatomies (Fig.1) suggests the existence of a central jet in the TAV and type-0 BAV but a jet skewed toward the smaller leaflet in the type-1 BAV model. The fibrosa (i.e., leaflet surface prone to calcification) WSS magnitudes in the type-0 BAV (TSM: 1.84 dyn/cm2) and type-1 BAV (TSM: 2.05 dyn/cm2) were found to be significantly higher than that in the TAV model (TSM: 0.55 dyn/cm2).
CONCLUSION: This study provides new evidence of the existence of abnormal hemodynamic stresses on BAV leaflets. The results provide new insights into the macro-scale valvular hemodynamics and are critical to the assessment of the hemodynamic theory of calcific aortic valve disease in BAV patients.
Figure 1. Snapshots of flow velocity field in TAV, type-0 and type-1 BAVs.
Author Disclosures: K. Cao: None. P. Sucosky: None.
This research has received full or partial funding support from the American Heart Association.
- © 2014 by American Heart Association, Inc.