Analysis of the formation mechanism and occurrence possibility of Post-Stenotic Dilatation of the aorta by CFD approach

Xuelan Zhang; Mingyao Luo; Kun Fang; Jiehua Li; Yuan Peng; Liancun Zheng; Chang Shu

doi:10.1016/j.cmpb.2020.105522

Analysis of the formation mechanism and occurrence possibility of Post-Stenotic Dilatation of the aorta by CFD approach

Comput Methods Programs Biomed. 2020 Oct:194:105522. doi: 10.1016/j.cmpb.2020.105522. Epub 2020 May 11.

Authors

Xuelan Zhang¹, Mingyao Luo², Kun Fang², Jiehua Li³, Yuan Peng³, Liancun Zheng⁴, Chang Shu⁵

Affiliations

¹ School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 10083, China; School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China.
² Department of Vascular Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China.
³ Department of Vascular Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410000, China.
⁴ School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China. Electronic address: liancunzheng@ustb.edu.cn.
⁵ Department of Vascular Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China. Electronic address: changshu01@yahoo.com.

PMID: 32422474
DOI: 10.1016/j.cmpb.2020.105522

Abstract

Background and objective: Post-Stenotic Dilatation (PSD), the common complication of coarctation of the aorta (COA), is a progressive disease involving aortic aneurysm and even rupture. However, there has been no definitive method that could investigate the mechanism of PSD formation, progression and rupture. The purpose of the present work is to analyze the mechanism behind PSD formation and to further assess the risk of COA patients with different coarctation degrees deteriorating into PSD.

Method: Three-dimensional non-Newtonian (Carreau-Yasuda) hemodynamic simulations are performed throughout the cardiac cycle, and a novel parameter (λ_ci¯ intensity) is proposed to evaluate the intensity of vortices within the aorta. The PSD geometry is reconstructed from Computed Tomography scans. To analyze the formation mechanism and occurrence possibility of PSD, the computer technology is utilized to restore the expansive and/or narrow regions to obtain its previous state (COA) and control group (Normal), and to modify the minimum diameter to obtain the aortas with different coarctation degrees. The clinical cases of pre- and post-operation are further introduced to verify the analysis.

Results: Compared with the Normal, the vortical structures with higher swirling strength are generated and accumulated at the downstream of the coarctation segment after COA occurrence, and partially disappear in the wake of PSD formation. The sequence of λ_ci¯ intensity is COA > PSD > Normal and pre-operation > post-operation. With increasing the degree of coarctation, the λ_ci¯ intensity is higher and the jet-flow becomes more drastic.

Conclusions: The formation of PSD is caused by the vortical structures with higher swirling strength accumulating at the downstream of the coarctation segment. An increase in coarctation degree elevates the risk of PSD occurrence and even aneurysmal dilatation.

Keywords: Aorta with different coarctation degrees; Hemodynamics; Post-Stenotic Dilatation of the aorta; Pre- and post-operation; Vortical structures.

MeSH terms

Aorta*
Aortic Coarctation* / diagnostic imaging
Constriction, Pathologic
Dilatation
Hemodynamics
Humans