Effects of Surgical Replacement Aortic Root Geometry on Aortic Valve Function using Fluid-Structure Interaction Simulations

Abstract

The coupling between the aortic valve and root, left ventricular outflow tract, ascending aorta, and blood circulation is crucial for full valve function. Aortic root aneurysms and dissections are known to impair aortic valve function even in cases when the valve would otherwise function normally. A valve-conserving procedure, the Yacoub II Operation (YIIO), aims to restore normal physiology by tailoring the aortic root geometry to the patient. However, the relationship between root structure, particularly the sinuses, and valve function remains insufficiently characterized to determine to what degree surgeons should aim for a physiologically shaped sinus. This study presents the development of a computational Fluid-Structure Interaction (FSI) platform to investigate the biomechanical performance of the aortic valve-root complex. An idealized, parametric model of the aortic root, based on an ellipsoid design derived from healthy CT images, was created to systematically assess structure–function relationships. Simulation results demonstrated that geometric parameters, particularly the sinotubular junction (STJ) diameter and ascending aorta diameter significantly influence valve performance. Smaller STJ and ascending aorta diameters were associated with delayed valve opening and closure, prolonged valve open times, reduced maximum geometric and effective orifice areas, lower peak flow rates, and diminished maximum blood velocities. Sinus geometry itself had less of an effect on these outcomes.  The developed FSI platform provides a predictive tool for aiding in surgical planning and outcomes in valve-conserving procedures such as the YIIO. Future work will focus on translating these findings to patient-specific models to enhance pre-operative assessment and long-term repair durability.