Hemodynamic analysis of a novel stent graft design with slit perforations in thoracic aortic aneurysm

ChiWei Ong; Fei Xiong; Foad Kabinejadian; Gideon Praveen Kumar; FangSen Cui; Gongfa Chen; Pei Ho; HwaLiang Leo

doi:10.1016/j.jbiomech.2019.01.019

Hemodynamic analysis of a novel stent graft design with slit perforations in thoracic aortic aneurysm

J Biomech. 2019 Mar 6:85:210-217. doi: 10.1016/j.jbiomech.2019.01.019. Epub 2019 Jan 19.

Authors

ChiWei Ong¹, Fei Xiong¹, Foad Kabinejadian², Gideon Praveen Kumar³, FangSen Cui³, Gongfa Chen⁴, Pei Ho⁵, HwaLiang Leo⁶

Affiliations

¹ Department of Biomedical Engineering, National University of Singapore, Singapore.
² Department of Biomedical Engineering, Tulane University, New Orleans, LA, USA.
³ Institute of High Performance Computing, A*STAR, Singapore 138632, Singapore.
⁴ Center of Computational Mechanics, Guangdong University of Technology, China.
⁵ Department of Cardiac, Thoracic & Vascular Surgery, National University Health System, Singapore.
⁶ Department of Biomedical Engineering, National University of Singapore, Singapore. Electronic address: bielhl@nus.edu.sg.

PMID: 30704763
DOI: 10.1016/j.jbiomech.2019.01.019

Abstract

Thoracic endovascular aortic repair (TEVAR) has been introduced as a less invasive approach to the treatment of thoracic aortic aneurysm (TAA). However, the effectiveness of TEVAR in the treatment of TAA is often limited due to the complex anatomy of aortic arch. Flow preservation at the three supra-aortic branches further increases the overall technical difficulty. This study proposes a novel stent graft design with slit perforations that can positively alter the hemodynamics at the aortic arch while maintaining blood flow to supra-aortic branches. We carried out a computational fluid dynamic (CFD) analysis to evaluate flow characteristics near stented aortic arch in simplified TAA models, followed by in-vitro experiments using particle image velocimetry (PIV) in a mock circulatory loop. The hemodynamics result was studied in terms of time-averaged wall shear stress (TAWSS), oscillating shear index (OSI), and endothelial cell action potential (ECAP). The results showed that the stent graft with slit perforations can reduce the disturbed flow region considerably. Furthermore, the effect of the slits on flow preservation to the supra-aortic branches was simulated and compared with experimental results. The effectiveness of the stent graft with slit perforations in preserving flow to the branches was demonstrated by both simulated and experimental results. Low TAWSS and elevated ECAP were observed in the aortic arch aneurysm after the placement of the stent graft with slits, implying the potential of thrombus formation in the aneurysm. On the other hand, the effects of the stent grafts with full-slit design and half-slit design on the shear stress did not differ significantly. The present analysis indicated that not only could the stent graft with slit perforations shield the aneurysm from rupture, but also it resulted in a favorable environment for thrombus that can contribute to the shrinkage of the aneurysm.

Keywords: Computational fluid dynamics; Flow preservation; Particle image velocimetry; Shear stress; Thoracic aortic aneurysm.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aortic Aneurysm, Thoracic* / physiopathology
Aortic Aneurysm, Thoracic* / therapy
Blood Vessel Prosthesis* / standards
Hemodynamics* / physiology
Humans
Models, Cardiovascular
Prosthesis Design*
Stents / standards
Stress, Mechanical
Thrombosis
Treatment Outcome