Assessment of the Combined Effects of Valve Phenotype and Aneurysm Progression on Ascending Thoracic Aortic Hemodynamics

In the context of ascending aorta hemodynamics, it is well established that both valve morphology and vessel geometry play a key role. However, the possibility of conducting systematic comparisons is limited by the challenges associated with acquiring patient-specific follow-up data. In this paper, we combined a novel definition for a parametric time-varying inlet velocity profile with a virtual aneurysm growth model to investigate the combined effects of valve morphology and aneurysm progression on aortic hemodynamics. We successfully modeled the reduced orifice area and eccentric inflow characteristic of bicuspid aortic valves and their consequent effects on hemodynamics. Controlled comparisons revealed that flow patterns and related biomarkers are primarily influenced by the presence of an eccentric inflow that induces disrupted hemodynamics, elevated wall shear stresses, and increased oscillatory indexes. While aneurysm growth exerts minimal influence on hemodynamic parameters for small diameter increases, its impact becomes more relevant with substantial aortic bulge enlargement, and it remains dependent on the specific valve phenotype. The current study underlines the pivotal role of aortic valve boundary conditions and the influence of eccentric inlet velocity on ascending aortic flow patterns in both healthy and aneurysmal conditions. Knowledge of valve morphology and the definition of corresponding inflow conditions are essential for patient-specific analyses when in vivo patient-specific boundary conditions are unavailable.