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You are here: Contents > 2017 > Volume 26 Number 4 July 2017 > AORTIC VALVE DISEASE > Stress Analysis of Transcatheter Aortic Valve Leaflets Under Dynamic Loading: Effect of Reduced Tissue Thickness

Stress Analysis of Transcatheter Aortic Valve Leaflets Under Dynamic Loading: Effect of Reduced Tissue Thickness

Mostafa Abbasi1, Ali N. Azadani1,2

1The DU Cardiovascular Biomechanics Laboratory, Department of Mechanical and Materials Engineering, University of Denver, Denver, Colorado, USA
2Electronic correspondence: ali.azadani@du.edu

Background and aim of the study: In order to accommodate transcatheter valves to miniaturized catheters, the leaflet thickness must be reduced to a value which is typically less than that of surgical bioprostheses. The study aim was to use finite-element simulations to determine the impact of the thickness reduction on stress and strain distribution.

Methods: A 23 mm transcatheter aortic valve (TAV) was modelled based on the Edwards SAPIEN XT (Edwards Lifesciences, Irvine, CA, USA). Finite-element (FE) analysis was performed using the ABAQUS/Explicit solver. An ensemble-averaged transvalvular pressure waveform measured from in-vitro tests conducted in a pulse duplicator was applied to the leaflets. Through a parametric study, uniform TAV leaflet thickness was reduced from 0.5 to 0.18 mm.

Results: By reducing leaflet thickness, significantly higher

stress values were found in the leaflet’s fixed edge during systole, and in the commissures during diastole. Through dynamic FE simulations, the highest stress values were found during systole in the leaflet fixed edge. In contrast, at the peak of diastole high-stress regions were mainly observed in the commissures. The peak stress was increased by 178% and 507% within the leaflets after reducing the thickness of 0.5 mm to 0.18 mm at the peak of systole and diastole, respectively.

Conclusion: The study results indicated that, the smaller the leaflet thickness, the higher the maximum principal stress. Increased mechanical stress on TAV leaflets may lead to accelerated tissue degeneration. By using a thinner leaflet, TAV durability may not atch with that of surgical bioprostheses.

The Journal of Heart Valve Disease 2017;26:386-396


Stress Analysis of Transcatheter Aortic Valve Leaflets Under Dynamic Loading: Effect of Reduced Tissue Thickness

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