Effect of Parametric Variation of Chordae Tendineae Structure on Simulated Atrioventricular Valve Closure

Many approaches have been used to model chordae tendineae geometries in finite element simulations of atrioventricular heart valves. Unfortunately, current "functional" chordae tendineae geometries lack anatomical fidelity (e.g., branching) that would be helpful when informing clinical decisions. The objectives of this work are (i) to improve synthetic chordae tendineae geometric fidelity to consider branching and (ii) to evaluate how the chordae tendineae geometry affects finite element simulations of valve closure.

In this work, we develop an open-source method to construct synthetic chordae tendineae geometries in the SlicerHeart Extension of 3D Slicer. The generated geometries are then used in FEBio finite element simulations of atrioventricular valve function to evaluate how variations in chordae tendineae geometry influence valve behavior. Effects are evaluated using functional and mechanical metrics. Three synthetic geometries were used (healthy mitral valve, mitral valve with annular dilation, and a tricuspid valve) and a patient specific healthy mitral valve.

Our findings demonstrated that altering the chordae tendineae geometry of a stereotypical mitral valve led to changes in clinically relevant valve metrics (regurgitant orifice area, contact area, and billowing volume) and valve mechanics (first principal strains). Specifically, cross sectional area had influence over 9 out of 10 valve closure metrics, followed by chordae tendineae density, length, radius and branches. The effects of these parameters can be drastic. For example, when primary chord density is decreased ROA increased by $75\%$ relative to baseline.

This study presents a flexible, open-source method for generating synthetic chordae tendineae with realistic branching structures. Further, we establish relationships between the chordae tendineae geometry and valve functional/mechanical metrics. This research contribution helps enrich our open-source workflow and brings the finite element simulations closer to use in a patient-specific clinical setting.