Longitudinal Distribution of Mechanical Stresses in Carotid Plaques of Symptomatic Patients

Thrysøe, Samuel A.; Oikawa, Minako; Yuan, Chun; Eldrup, Nikolaj; Klaerke, A; Paaske, William P.; Falk, Erling; Kim, Won Yong; Nygaard, Jens Vinge

doi:10.1161/strokeaha.109.571588

Cited by 25 publications

(12 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…performed at the most severely narrowed longitudinal section of the diseased MCA, as shown in Figure 1, in accordance with previous studies on carotid and coronary arteries (12,13).…”

Section: Measurements and Definition Of The Specific Indices Of Wss Asupporting

confidence: 91%

Characteristics of Wall Shear Stress and Pressure of Intracranial Atherosclerosis Analyzed by a Computational Fluid Dynamics Model: A Pilot Study

et al. 2020

View full text Add to dashboard Cite

Background: Although wall shear stress (WSS) and pressure play important roles in plaque vulnerability, characteristics of the two indices in intracranial atherosclerosis (ICAS) have not been fully investigated yet. This study aimed to elucidate this issue by means of establishing a non-invasive computational fluid dynamics method with time-of-flight magnetic resonance angiography (TOF-MRA) of the whole cerebral artery. Materials and Methods: Subjects with symptomatic ICAS in the middle cerebral artery domain were enrolled, excluding those with concomitant internal carotid artery stenosis. Based on patient-specific TOF-MRA images for three-dimensional (3D) meshes and arterial blood pressure with patient-specific carotid artery ultrasonography for inlet boundary conditions, patients' three-dimensional hemodynamics were modeled by a finite element method governed by Navier-Stokes equations. Results: Among the 55 atherosclerotic lesions analyzed by this TOF-MRA based computational fluid dynamics model, the maximum WSS (WSS max) was most frequently detected at the apex points and the upper half of the upstream sections of the lesions, whereas the maximum pressure was most often located at the lower half of the upstream sections. As the percent stenosis increases, the relative value of WSS max and pressure drop increased with significantly increasing steep beyond 50% stenosis. Moreover, WSS max was found to linearly correlate with pressure drop in ICAS. Conclusions: This study on ICAS revealed certain trends of longitudinal distribution of WSS and pressure and the influences of percent stenosis on cerebral hemodynamics, as well as the correlations between WSS and pressure drop. It represents a step forward in applying computational flow simulation techniques in studying ICAS and stroke, in a patient-specific manner.

show abstract

“…performed at the most severely narrowed longitudinal section of the diseased MCA, as shown in Figure 1, in accordance with previous studies on carotid and coronary arteries (12,13).…”

Section: Measurements and Definition Of The Specific Indices Of Wss Asupporting

confidence: 91%

Characteristics of Wall Shear Stress and Pressure of Intracranial Atherosclerosis Analyzed by a Computational Fluid Dynamics Model: A Pilot Study

et al. 2020

View full text Add to dashboard Cite

show abstract

“…In advanced stages of atherosclerosis, the presence of lumen-narrowing lesions dramatically alters the local hemodynamic conditions in affected arteries. As reported by Thrysøe et al, 2 peak mechanical stress levels are asymmetrically distributed along the carotid plaque, with 50% occurring proximal and 25% distal to the point of maximal stenosis, and correlate inversely with the fibrous cap (FC) thickness. These differences in mechanical load distribution can affect cellular composition and stability of the lesions.…”

mentioning

confidence: 69%

“…2 Monitoring the longitudinal asymmetry of the FC thickness, in particular in asymptomatic patients, could thus contribute to the detection of progressive plaque vulnerability and improve patient management. Taken together, the results of our study provide evidence supporting the role of local hemodynamic factors in plaque destabilization and in the structural differentiation between stable and rupture-prone plaques.…”

Section: Cicha Et Al Mechanisms Of Plaque Rupture At Upstream Shouldementioning

confidence: 99%

Carotid Plaque Vulnerability

Cicha

Wörner

Urschel

et al. 2011

Stroke

View full text Add to dashboard Cite

Background and Purpose-Rupture of atherosclerotic plaques is one of the main causes of ischemic strokes. The aim of this study was to investigate carotid plaque vulnerability markers in relation to blood flow direction and the mechanisms leading to plaque rupture at the upstream side of carotid stenoses. Methods-Frequency and location of rupture, endothelial erosion, neovascularization, and hemorrhage were determined in longitudinal sections of 80 human carotid specimens. Plaques were immunohistochemically analyzed for markers of vulnerability. Plaque geometry was measured to reconstruct shape profiles of ruptured versus stable plaques and to perform computational fluid dynamics analyses. Results-In 86% of ruptured plaques, rupture was observed upstream. In this region, neovascularization and hemorrhage were increased, along with increased immunoreactivity of vascular endothelial and connective tissue growth factor, whereas endothelial erosion was more frequent downstream. Proteolytic enzymes, mast cell chymase and cathepsin L, and the proapoptotic protein Bax showed significantly higher expression upstream as compared with the downstream shoulder of atherosclerotic lesions. Comparison of geometric profiles for ruptured and stable plaques showed increased longitudinal asymmetry of fibrous cap and lipid core thickness in ruptured plaques. The specific geometry of plaques ruptured upstream induced increased levels of shear stress and increased pressure drop between the upstream and the downstream plaque shoulders. Conclusions-Vulnerability of the upstream plaque region is associated with enhanced neovascularization, hemorrhage, and cap thinning induced by proteolytic and proapoptotic mechanisms. These processes are reflected in structural plaque characteristics, analyses of which could improve the efficacy of vascular diagnostics and prevention.

show abstract

“…strain relationship was used to specify the mechanical properties of the plaque components [17,18]. Two examples of velocity fields, first principal stress distributions, and velocity streamlines are presented in Figure 3.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Carotid Plaque Morphology on Longitudinal Fibrous Cap Stress Levels

Thrysøe¹,

Stegmann²,

Eldrup³

et al. 2012

WJM

Self Cite

View full text Add to dashboard Cite

Background and Purpose: Rupture of vulnerable carotid atherosclerotic plaques is a major cause of stroke. Stress levels may reflect risk of rupture in patients with carotid atherosclerotic plaques. Features thought to influence the risk of plaque rupture include the degree of stenosis, lipid-rich necrotic core (LR-NC) size, and thickness of the protective fibrous caps. We used computational models to investigate the effect of these variables on fibrous cap stress levels. Methods: Two-way coupled fluid-structure interaction longitudinal 2D simulations were performed on a bifurcation model based on idealized geometry derived from a symptomatic patient. Models with varying degrees of stenosis (50% -95%), fibrous cap thicknesses (0.05 -1 mm), and LR-NC sizes (2 × 1 mm -6 × 3 mm) were simulated. The stress distribution for each model was calculated and peak principal stresses extracted. Regression analysis was used for assessing the relationship between the variables and stress levels. Results: Mechanical stresses increased with decreasing fibrous cap thicknesses (ß = -0.905, p < 0.001) and increasing LR-NC sizes (ß = 0.262, p < 0.001). The degree of stenosis (ß = 0.024, p = 0.344) and LR-NC placement (ß = -0.001, p = 0.979) had insignificant effects on mechanical stress levels. Conclusions: Thin-capped plaques with large atheromas, known predictors of plaque vulnerability, were shown to exhibit the greatest mechanical stress levels.

show abstract

Longitudinal Distribution of Mechanical Stresses in Carotid Plaques of Symptomatic Patients

Cited by 25 publications

References 11 publications

Characteristics of Wall Shear Stress and Pressure of Intracranial Atherosclerosis Analyzed by a Computational Fluid Dynamics Model: A Pilot Study

Characteristics of Wall Shear Stress and Pressure of Intracranial Atherosclerosis Analyzed by a Computational Fluid Dynamics Model: A Pilot Study

Carotid Plaque Vulnerability

The Effect of Carotid Plaque Morphology on Longitudinal Fibrous Cap Stress Levels

Contact Info

Product

Resources

About