Date of Award

1-1-2018

Document Type

Thesis

Degree Name

M.S.

Department

Mechanical Engineering

First Advisor

Ali N. Azadani, Ph.D.

Keywords

LAA, Appendage, FEA

Abstract

The left atrial appendage has been a historically understudied region of the heart until fairly recently with the new understanding of its role in the stroke pathway of patients with atrial fibrillation. The goal of this study is to take a look at the biomechanical behavior of the left atrium and left atrial appendage under normal physiological loading conditions using material properties taken from biaxial stretch tests. Several different options for material properties models were tested and biaxial stretch test data of cadaveric human tissue samples for the left atrium and appendage were fit to a Fung-type strain-energy function for input into simulation. Simulations were performed on geometry of the left atrium and appendage extracted from computed tomographical images of a single patient spanning from the pulmonary veins to the mitral valve annulus. Physiological pressure loading conditions were simulated at 5 mmHg, 7.5 mmHg, 10 mmHg, 15 mmHg, and 20 mmHg over two cardiac cycles. Results showed that peak stresses and strains were concentrated at branches in the atrium as well as the ostial entrance to the appendage. Ostial diameter of the appendage was measured across to axes and showed increases from a baseline of 1.347 cm x 2.927 cm in the unloaded configuration up to a size of 1.749 cm x 3.219 cm in the loaded configuration. Finite element simulations may be a useful tool for improving patient treatment options, especially when it comes to mechanical left atrial appendage occlusion devices.

Provenance

Received from ProQuest

Rights holder

Sky Tianqi Gao

File size

67 p.

File format

application/pdf

Language

en

Discipline

Bioengineering

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