Orientation effects of bicuspid aortic valve with mild/severe aortic stenosis on aortic hemodynamics: a parametric study

Abstract

While bicuspid aortic valve (BAV) shows different phenotypes associated with aortic aneurysm and valvular dysfunction due to aortic stenosis (AS), hemodynamics in patients with stenotic BAVs remains poorly understood. Here we address a study of the effects of valve phenotypes on aortic hemodynamics in different configurations of AS using an image-based subject-specific left ventricle (LV)-aorta integrated computational model. The model was built up by combining both MRI images and realistic motions of aortic valve, mitral valve, and LV apex as well as its contraction and dilatation of a healthy subject. Physiological boundary conditions were given based on a parameter-adjusted 0-1D cardiovascular model. Symmetrical BAV models with mild and severe stenosis were constructed with the orientation angle varying every 15° from 0° to 165° with regards to mitral valve while within a planar disc and the orientation effects on aortic hemodynamics were systematically investigated. Our results revealed that systolic jets in aorta were dominated by a combination of valve orientation and AS. Furthermore the hemodynamic indices of maximum wall shear stress (WSS), oscillatory shear index (OSI), and axial energy loss also demonstrated a feature of phenotype-and stenosis-dependency, pointing to the importance of taking into account the valve configuration in clinical decision-making on BAV patients.