Influence of Geometric Changes in the Thoracic Aorta due to Arterial Switch Operations on the Wall Shear Stress Distribution.

Tomohiro Fukui,Hiroaki Asama,Koji Morinishi,Toshiyuki Itoi,Manabu Kimura

doi:10.2174/1874120701711010009

Abstract

Background:The transposition of the great arteries (TGA) is one of the most severe congenital heart diseases. The arterial switch operation (ASO) is the preferred procedure to treat TGA. Although numerous reports have shown good results after ASOs, some patients suffer from circulatory system problems following the procedure. One reason for problems post-ASO is the local changes in the curvature and torsion of the thoracic aorta.Objective:The influence of these geometric changes on the blood flow field needs to be investigated in detail to consider possible cardiovascular problems after an ASO.Method:In this study, we conduct blood flow simulations in the thoracic aorta post-ASO, evaluate geometric changes in the aorta due to the ASO in terms of curvature and torsion, and consider the effect of geometric changes on blood flow in the aorta.Results:It was found that a large curvature near the aortic root causes an increase in the maximal wall shear stress value in the middle systole. Moreover, a large torsion results in a circumferential change in the maximal wall shear stress region. It was also found that the maximal wall shear stress in the post-ASO models is significantly higher than that in the normal models. This indicates that the aortic aneurysm initiation risk for a post-ASO artery may be higher than that of a normal artery.Conclusion:To reduce the risk of initiating an aneurism, it is suggested that the curvature near the aortic root should be decreased during the ASO.

Highlights

The geometry of the thoracic aorta is complicated with varying curvature, torsion, branches, and tapering, and the area is well known for its localization of aortic aneurysms, from the root of the ascending aorta to the aortic arch
To reduce the risk of initiating an aneurism, it is suggested that the curvature near the aortic root should be decreased during the arterial switch operation (ASO)
The curvature and torsion are both related to the maximal wall shear stress in the aorta

Summary

Introduction

The geometry of the thoracic aorta is complicated with varying curvature, torsion, branches, and tapering, and the area is well known for its localization of aortic aneurysms, from the root of the ascending aorta to the aortic arch. This is attributed to the local wall shear stress distribution changes resulting from its complicated geometry. The arterial switch operation (ASO) is the preferred procedure to treat TGA. One reason for problems post-ASO is the local changes in the curvature and torsion of the thoracic aorta

Methods

Results

Discussion

Conclusion