Hemodynamics and Wall Mechanics after Surgical Repair of Aortic Arch: Implication for Better Clinical Decisions

Siyeong Ju,Linxia Gu,Shengmao Lin,Ibrahim Abdullah

doi:10.3390/app9040807

Siyeong Ju, Linxia Gu + Show 2 more

Open Access

https://doi.org/10.3390/app9040807

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Abstract

Graft repair of aortic coarctation is commonly used to mimic the physiological aortic arch shape and function. Various graft materials and shapes have been adopted for the surgery. The goal of this work is to quantitatively assess the impact of graft materials and shapes in the hemodynamics and wall mechanics of the restored aortic arch and its correlation with clinical outcomes. A three-dimensional aortic arch model was reconstructed from magnetic resonance images. The fluid–structure interaction (FSI) analysis was performed to characterize the hemodynamics and solid wall mechanics of the repaired aortic arch. Two graft shapes (i.e., a half-moon shape and a crescent one) were considered. Material choices of the aortic arch repair included three commonly used graft materials (i.e., polytetrafluoroethylene (PTFE) synthetic graft, CorMatrix extracellular matrix, and pulmonary homograft) as well as one native tissue serving as a control. The pathological hemodynamic parameters, in terms of the percentage area of low wall shear stress (WSS), high oscillatory shear index (OSI), and high relative residence time (RRT), were quantified to be associated with potential clinical outcomes. Results have shown that the peak von Mises stress for the aortic arch repaired by the crescent graft was 76% less than that of the half-moon graft. Flow disturbance and recirculation were also minimized with the crescent graft. Moreover, pathological hemodynamic parameters were significantly reduced with the crescent graft. The graft material mismatch with the surrounding tissue aggregated the stress concentration on the aortic wall, but had minimal impact on flow dynamics. The present work demonstrated the role and importance of the graft geometry and materials on hemodynamics and wall mechanics, which could guide optimal graft decisions towards better clinical outcomes.

Highlights

Aortic coarctation (CoA) is one of the common congenital heart defects [1]
The major complications include recoarctation and aneurysms at the graft site. These complications are well acknowledged to be associated with altered biomechanical environments
The mechanical environment of the aortic arch altered by the graft shapes, as well as the PTFE, CorMatrix, and pulmonary grafts, was characterized in terms of wall shear stress (WSS), oscillatory shear index (OSI), relative residence time (RRT), and von

Summary

Introduction

Aortic coarctation (CoA) (i.e., a narrowing in the aorta) is one of the common congenital heart defects [1]. A stiff Dacron graft, adopted in 1952, resulted in early and late late complications following repair mismatch by material mismatchsoft[7]. The impacts of graft shapes materials on the hemodynamics and wall mechanics of the aorticofarch aortic arch following surgical repair were characterized. There werebya their total anterior of five model in terms graft configurations in terms of graft and shapes.and Their roles in mechanics the hemodynamics and solid wall materials and shapes. Mises stress (OSI), relative(WSS), residence time (RRT), von(OSI), Misesrelative stress distributions on the aortic wall were obtained distributions the aortic were These obtained and compared among five choices. These and comparedon among the fivewall choices.

Materials and Methods

Results

Influence of Graft Shapes

Influence of Graft Materials

Discussions