Quantitative in silico analysis for patient-specific annuloplasty in bicuspid aortic valve regurgitation

Bicuspid aortic valve (BAV) patients are more predisposed to aortic regurgitation. Annuloplasty is a crucial therapeutic intervention, however, determining its ideal size remains a clinical challenge. This study aims to quantify the effects of varying annuloplasty sizes on treating BAV regurgitation, providing optimal size range for effective treatment while avoiding complications. Annuloplasty was simulated on a patient-specific BAV model using 19-27 mm diameter Hegar dilators to reduce the basal ring and elastic ring sutures to constrain it. Finite element simulation was performed to simulate BAV motion, followed by computational fluid dynamics simulation to obtain hemodynamic parameters at peak systole. Results show that as the basal ring size decreased, the leaflet coaptation area increased, accompanied by a reduction in maximum principal stress at the coaptation zone. However, the reduction in annuloplasty size significantly elevated the peak systolic flow velocity within the sinus, particularly near the basal ring, leading to a higher wall shear stress in the adjacent region. Moreover, an excessively small basal ring diameter induced a sharp increase in transvalvular pressure gradient. These findings suggest that the small-sized annuloplasty enhances BAV function and durability, whereas excessive ring reduction may aggravate mechanical burden on the aortic root, potentially resulting in long-term complications such as tissue damage and stenosis. Thus, these factors establish critical upper and lower limits for optimal annuloplasty sizing.