Abstract:
"Aortic root numeric model: Annulus diameter prediction of effective height and coaptation in post-aortic valve repair"
The successful repair of the aortic valve and root depends critically on achieving optimal leaflet coaptation and effective height, which are directly influenced by the dimensions of the aortic annulus (AA). This study delves into the biomechanical relationship between the aortic annulus diameter and key performance metrics of the aortic valve following repair, including maximum principal stress, strain energy density, coaptation area, and effective height. Understanding these interdependencies is crucial for optimizing surgical outcomes and ensuring long-term valve durability.
The methodology involved the development of sophisticated three-dimensional fluid-structure interaction (FSI) models of the aortic valve and root. Six distinct cases were numerically modeled, covering a range of AA diameters from 20 mm to 30 mm. The structural component of the model incorporated flexible cusps within a compliant aortic root, endowed with material properties closely mimicking physiological values to ensure biomechanical fidelity. For the fluid dynamics aspect, blood hemodynamics were simulated under physiological diastolic pressures in both the left ventricle and ascending aorta. Additionally, to specifically calculate effective height, no-flow models were utilized, mimicking clinical measurement conditions, where the cusps were loaded with a transvalvular pressure decrease, while all other parameters remained identical to the FSI models.
The biomechanical results revealed a critical threshold: aortic valve models with an AA diameter ranging from 20 mm to 26 mm consistently achieved full closure, indicating proper coaptation. However, models with AA diameters between 28 mm and 30 mm exhibited only partial closure, highlighting a significant compromise in valve function. This detailed numeric analysis provides essential insights into how annular diameter manipulation during aortic valve repair impacts the biomechanical performance, stress distribution, and overall efficacy of the repaired valve, offering predictive capabilities valuable for surgical planning and improving patient outcomes.
