A Perspective Review on Numerical Simulations of Hemodynamics in Aortic Dissection

Abstract

Aortic dissection, characterized by separation of the layers of the aortic wall, poses a significant challenge for clinicians. While type A aortic dissection patients are normally managed using surgical treatment, optimal treatment strategy for type B aortic dissection remains controversial and requires further evaluation. Although aortic diameter measured by CT angiography has been clinically used as a guideline to predict dilation in aortic dissection, hemodynamic parameters (e.g., pressure and wall shear stress), geometrical factors, and composition of the aorta wall are known to substantially affect disease progression. Due to the limitations of cardiac imaging modalities, numerical simulations have been widely used for the prediction of disease progression and therapeutic outcomes, by providing detailed insights into the hemodynamics. This paper presents a comprehensive review of the existing numerical models developed to investigate reasons behind tear initiation and progression, as well as the effectiveness of various treatment strategies, particularly the stent graft treatment.

A computational model for false lumen thrombosis in type B aortic dissection following thoracic endovascular repair

“…In the last decade, computational fluid dynamics (CFD) studies have provided better insights into the hemodynamic environment associated with aortic dissection (AD), and have allowed the estimation of parameters such as wall shear stress (WSS) and pressure, which are difficult to measure in vivo (Sun and Chaichana, 2016;Doyle and Norman, 2016). CFD studies have demonstrated that flow in AD is disturbed, with a high velocity jet through the primary entry tear, strong recirculation in the FL and near the tears and large variations in WSS (Tse et al, 2011;Chen et al, 2013;Alimohammadi et al, 2014;Cheng et al, 2013;Wan Ab Naim et al;, Dillon-Murphy et al, 2015Ahmed et al, 2016). Several authors have compared flow in pre and post-TEVAR aortas, in order to investigate its effect on AD hemodynamics (Karmonik et al, 2010;Midulla et al, 2012;Cheng et al, 2015;Sun and Chaichana, 2016), and a recent study by Nauta et al (2017) focused on the influence of disturbed flow on the development of thrombus by evaluating platelet activation potential.…”

Coupled Multiphysics Modeling of Aortic Dissection

“…Blood is considered an incompressible Newtonian fluid, which is a reasonable assumption balancing computational cost and accuracy made in line with numerous studies in literature [1,6]. Therefore, balance of linear momentum and continuity equation are expressed using the fluid velocity v and pressure p as primary variables in Arbitrary-Lagrangian-Eulerian (ALE) formulation, posed in the moving domain Ω f (t) as…”

“…Despite the remarkable advancements in the field of computational biomechanics and haemodynamics during the recent years (cf. for work related to aortic dissection [1][2][3][4][5][6]), numerical simulations of fluidstructure interaction in patient-specific cardiovascular settings remain challenging. Nonetheless, several advancements with regards to simulating aortic dissection with fluid-structure interaction are reported in literature.…”

CT patterns of acute type A aortic arch dissection: longer, higher, more anterior

“…This could result from the appearance of turbulent (especially helical) flow patterns in aortic dissections, as can occur in healthy subjects 24,25 and also suggested by simulations. 26 The distribution of the positions of the false lumens suggests that from a variable position in the ascending aorta, the false lumen rotates to the lateral quadrants of the horizontal segment of the arch, and turns again to a posterior position in the descending aorta.…”