Computational Modeling for Surgical Reconstruction of Aortic Valve by Using Autologous Pericardium

Abstract

The objective of this study was to evaluate the clinical effectiveness of surgical reconstruction of aortic valve using autologous pericardium, and the hemodynamic impact of matching the circumferential direction of the trimmed leaflet to inherent fiber orientation of the pericardium during surgery. A patient specific aortic valve model was built based on CTA data. The reconstructive surgery was carried out on the model following normal operating procedures. FSI simulation was performed to analyze the hemodynamic characteristics among the diseased model, normal model and three operative models with different misaligned angles between the circumferential direction of the substitute and inherent fiber orientation. The differences of EOA, velocity distribution, stress and strain on leaflets, and the valve deformation between the five models were compared and analyzed. The results showed that reconstructive surgery helps enlarge EOA, reduce abnormity of leaflet motion and blood ejection compared to diseased model. There was no significant difference between operative models with different misaligned angles in terms of leaflet motion and flow pattern, but as the misaligned angle increased, greater strain and deformation were observed on leaflets during the diastolic period. The present study demonstrated the instant clinical effectiveness of the reconstructive surgery of aortic valve by the improvement of EOA and flow pattern, and suggested that during the operation it may be unnecessary to match the circumferential direction of the substitute to inherent fiber orientation of the pericardium since the hemodynamic characteristics were insensitive to the fiber alignment, but the strain and deformation increment on the substitutes during diastolic period still raised concern about their durability.

Biaxial Estimation of Biomechanical Constitutive Parameters of Passive Porcine Sclera Soft Tissue

“…On the other hand, the Choi-Vito model had the smallest variance in the material parameters with deviations between 31% and 91%. This result might not be surprising considering that the Choi-Vito model was originally formulated for the pericardium tissue [42,48,49] which, in much respect, may be similar in functionality to the sclera tissue. The implications of such deviations in terms of applying the estimated average material parameters directly to finite element (FE) models is problematic, and this has been discussed in the next section.…”

A Fluid–Structure Interaction Study of Different Bicuspid Aortic Valve Phenotypes Throughout the Cardiac Cycle

“…In the simulation study, the material of aortic valve was assumed as an isotropic material to avoid the problem of excessive distortion of the mesh during the contact process of the leaflets. In fact, the aortic valve tissue exhibits obvious fiber arrangement ( Grande-Allen et al, 2001 ; Feng et al, 2020 ), which belongs to an anisotropic material. Studies have shown that the isotropic and anisotropic leaflet materials may have little effect on the study of hemodynamic performance ( Weston et al, 1999 ; Ge and Sotiropoulos, 2010 ).…”

Effect of Valve Height on the Opening and Closing Performance of the Aortic Valve Under Aortic Root Dilatation

“…Second, in this simulation study, the material of the aortic valve was assumed to have isotropic and linear elastic material properties to simplify the computation and improve the feasibility of the analysis and avoid the problem of excessive distortion of the mesh during the contact process of the leaflets. In fact, the aortic valve tissue exhibits an obvious fiber arrangement (Feng et al, 2020 ), which is a characteristic of a hyperelastic and anisotropic material. Studies have shown that isotropic and anisotropic leaflet materials are not expected to significantly affect the dynamic performance of leaflets (Hammer et al, 2016 ; Cao and Sucosky, 2017 ).…”

“…The shell element was selected as the element type of the valve and vessel wall. Physiologically speaking, the aortic valve tissue exhibits an obvious fiber arrangement (Feng et al, 2020 ), which belongs to a hyperelastic and anisotropic material. In fact, during systole, valve leaflets typically experience strains below 10% (Weinberg and Mofrad, 2007 ; Cao and Sucosky, 2017 ) and essentially behave as an isotropic material (Billiar and Sacks, 2000 ).…”