Wall shear stress gradient is independently associated with middle cerebral artery aneurysm development: a case-control CFD patient-specific study based on 77 patients

Abstract Background Previously published computational fluid dynamics (CFD) studies regarding intracranial aneurysm (IA) formation present conflicting results. Our study analysed the involvement of the combination of high wall shear stress (WSS) and a positive WSS gradient (WSSG) in IA formation. Methods We designed a case-control study with a selection of 38 patients with an unruptured middle cerebral artery (MCA) aneurysm and 39 non-aneurysmal controls to determine the involvement of WSS, oscillatory shear index (OSI), the WSSG and its absolute value (absWSSG) in aneurysm formation based on patient-specific CFD simulations using velocity profiles obtained from transcranial colour-coded sonography. Results Among the analysed parameters, only the WSSG had significantly higher values compared to the controls (11.05 vs − 14.76 [Pa/mm], P = 0.020). The WSS, absWSSG and OSI values were not significantly different between the analysed groups. Logistic regression analysis identified WSS and WSSG as significant co-predictors for MCA aneurysm formation, but only the WSSG turned out to be a significant independent prognosticator (OR: 1.009; 95% CI: 1.001–1.017; P = 0.025). Significantly more patients (23/38) in the case group had haemodynamic regions of high WSS combined with a positive WSSG near the bifurcation apex, while in the control group, high WSS was usually accompanied by a negative WSSG (14/39). From the analysis of the ROC curve for WSSG, the area under the curve (AUC) was 0.654, with the optimal cut-off value −0.37 Pa/mm. The largest AUC was recognised for combined WSS and WSSG (AUC = 0.671). Our data confirmed that aneurysms tend to form near the bifurcation apices in regions of high WSS values accompanied by positive WSSG. Conclusions The development of IAs is determined by an independent effect of haemodynamic factors. High WSS impacts MCA aneurysm formation, while a positive WSSG mainly promotes this process.

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Low Wall Shear Stress Is Independently Associated With the Rupture Status of Middle Cerebral Artery Aneurysms

Stroke ◽

10.1161/strokeaha.112.675306 ◽

2013 ◽

Vol 44 (2) ◽

pp. 519-521 ◽

Cited By ~ 115

Author(s):

Yoichi Miura ◽

Fujimaro Ishida ◽

Yasuyuki Umeda ◽

Hiroshi Tanemura ◽

Hidenori Suzuki ◽

...

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Middle Cerebral Artery ◽

Cerebral Artery ◽

Wall Shear ◽

Middle Cerebral Artery Aneurysms

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Impact of blood rheology on wall shear stress in a model of the middle cerebral artery

Interface Focus ◽

10.1098/rsfs.2012.0094 ◽

2013 ◽

Vol 3 (2) ◽

pp. 20120094 ◽

Cited By ~ 26

Author(s):

Miguel O. Bernabeu ◽

Rupert W. Nash ◽

Derek Groen ◽

Hywel B. Carver ◽

James Hetherington ◽

...

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Middle Cerebral Artery ◽

Cerebral Artery ◽

Decomposition Analysis ◽

Blood Rheology ◽

Vascular Pathology ◽

Newtonian Model ◽

Wall Shear ◽

The Impact

Perturbations to the homeostatic distribution of mechanical forces exerted by blood on the endothelial layer have been correlated with vascular pathologies, including intracranial aneurysms and atherosclerosis. Recent computational work suggests that, in order to correctly characterize such forces, the shear-thinning properties of blood must be taken into account. To the best of our knowledge, these findings have never been compared against experimentally observed pathological thresholds. In this work, we apply the three-band diagram (TBD) analysis due to Gizzi et al. (Gizzi et al. 2011 Three-band decomposition analysis of wall shear stress in pulsatile flows. Phys. Rev. E 83 , 031902. ( doi:10.1103/PhysRevE.83.031902 )) to assess the impact of the choice of blood rheology model on a computational model of the right middle cerebral artery. Our results show that, in the model under study, the differences between the wall shear stress predicted by a Newtonian model and the well-known Carreau–Yasuda generalized Newtonian model are only significant if the vascular pathology under study is associated with a pathological threshold in the range 0.94–1.56 Pa, where the results of the TBD analysis of the rheology models considered differs. Otherwise, we observe no significant differences.

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Wall Shear Stress in the Middle Cerebral Artery of HM II Patients - A Prospective, Mechanistic Study Using Vector Flow Mapping

The Journal of Heart and Lung Transplantation ◽

10.1016/j.healun.2019.01.1080 ◽

2019 ◽

Vol 38 (4) ◽

pp. S424

Author(s):

K. Akiyama ◽

R. Ji ◽

F. Castagna ◽

A. Pinsino ◽

J.R. Cockcroft ◽

...

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Middle Cerebral Artery ◽

Cerebral Artery ◽

Mechanistic Study ◽

Flow Mapping ◽

Vector Flow Mapping ◽

Wall Shear

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Statistical wall shear stress maps of ruptured and unruptured middle cerebral artery aneurysms

Journal of The Royal Society Interface ◽

10.1098/rsif.2011.0490 ◽

2011 ◽

Vol 9 (69) ◽

pp. 677-688 ◽

Cited By ~ 37

Author(s):

L. Goubergrits ◽

J. Schaller ◽

U. Kertzscher ◽

N. van den Bruck ◽

K. Poethkow ◽

...

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Middle Cerebral Artery ◽

Cerebral Artery ◽

Dimensional Space ◽

Neck Region ◽

Spherical Shape ◽

Unruptured Aneurysms ◽

Ruptured Aneurysms ◽

Wall Shear

Haemodynamics and morphology play an important role in the genesis, growth and rupture of cerebral aneurysms. The goal of this study was to generate and analyse statistical wall shear stress (WSS) distributions and shapes in middle cerebral artery (MCA) saccular aneurysms. Unsteady flow was simulated in seven ruptured and 15 unruptured MCA aneurysms. In order to compare these results, all geometries must be brought in a uniform coordinate system. For this, aneurysms with corresponding WSS data were transformed into a uniform spherical shape; then, all geometries were uniformly aligned in three-dimensional space. Subsequently, we compared statistical WSS maps and surfaces of ruptured and unruptured aneurysms. No significant ( p > 0.05) differences exist between ruptured and unruptured aneurysms regarding radius and mean WSS. In unruptured aneurysms, statistical WSS map relates regions with high (greater than 3 Pa) WSS to the neck region. In ruptured aneurysms, additional areas with high WSS contiguous to regions of low (less than 1 Pa) WSS are found in the dome region. In ruptured aneurysms, we found significantly lower WSS. The averaged aneurysm surface of unruptured aneurysms is round shaped, whereas the averaged surface of ruptured cases is multi-lobular. Our results confirm the hypothesis of low WSS and irregular shape as the essential rupture risk parameters.

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Patient-Specific Modelling of Aortic Arch Wall Shear Stress Patterns in Patients With Marfan Syndrome

ASME 2009 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2009-206340 ◽

2009 ◽

Author(s):

Bram Trachet ◽

Daniel Devos ◽

Julie De Backer ◽

Anne De Paepe ◽

Bart L. Loeys ◽

...

Keyword(s):

Shear Stress ◽

Aortic Aneurysm ◽

Wall Shear Stress ◽

Marfan Syndrome ◽

Aortic Root ◽

Arterial System ◽

Patient Specific ◽

Physiological Data ◽

Aneurysm Formation ◽

Wall Shear

Marfan syndrome (MFS) is a genetic connective tissue disorder with a high prevalence of aortic aneurysm formation (a pathological dilatation of the aorta), typically at the aortic root. The disorder is caused by mutations in the gene encoding fibrillin-1 [1]. Recently, it has been shown in mouse models that selected manifestations of MFS, such as aortic aneurysm formation, can be explained by excessive signaling by the transforming growth factor–beta (TGF-beta) family of cytokines [2]. Although the footprint of the disease is clearly genetic, there is still a role for (computational) biomechanics and hemodynamics to elucidate why aneurysms develop preferentially at the level of the aortic root, since the genetic defect affects the entire (arterial) system. One of the most obvious parameters to study is the arterial wall shear stress (WSS). WSS plays an important role in the regulation of the vascular system and is considered a significant factor in the development and progression of cardiovascular disease in humans. Low and/or oscillating values of WSS have been associated with the formation of atherosclerotic lesions [3] and with the growth of aneurysms [4]. It is, however, hard to show a link between low WSS and aneurysm initiation, since in most cases the geometrical and physiological data are lacking during the first and most important stages of the aneurysm development. Furthermore follow-up studies in human patients are difficult, since aneurysms grow very slowly (only 0.9 mm/year in MFS patients treated with beta-blockers) and it will take several years before significant changes will have taken place. Therefore, in this study, we have computed the aortic flow field and WSS patterns for 5 different MFS patients with ages varying from 14 to 54 years old, in order to get an idea about the effect of age on the development of the disease.

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Effects of Elasticity on Wall Shear Stress in Patient-Specific Aneurysm of Cerebral Artery

Journal of Flow Control Measurement &amp Visualization ◽

10.4236/jfcmv.2019.72006 ◽

2019 ◽

Vol 07 (02) ◽

pp. 73-86

Author(s):

Ryuhei Yamaguchi ◽

Taihei Kotani ◽

Gaku Tanaka ◽

Simon Tupin ◽

Kahar Osman ◽

...

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Cerebral Artery ◽

Patient Specific ◽

Wall Shear

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THE EFFECT OF ARTERY BIFURCATION ANGLES ON FLUID FLOW AND WALL SHEAR STRESS IN THE MIDDLE CEREBRAL ARTERY

10.15368/theses.2014.168 ◽

2014 ◽

Author(s):

Zachary Ramey Jones

Keyword(s):

Shear Stress ◽

Fluid Flow ◽

Wall Shear Stress ◽

Middle Cerebral Artery ◽

Cerebral Artery ◽

Wall Shear

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Genetic correlates of wall shear stress in a patient-specific 3D-printed cerebral aneurysm model

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2018-014669 ◽

2019 ◽

Vol 11 (10) ◽

pp. 999-1003 ◽

Cited By ~ 6

Author(s):

Michael R Levitt ◽

Christian Mandrycky ◽

Ashley Abel ◽

Cory M Kelly ◽

Samuel Levy ◽

...

Keyword(s):

Endothelial Cells ◽

Shear Stress ◽

Wall Shear Stress ◽

Cerebral Aneurysm ◽

Cell Morphology ◽

Patient Specific ◽

Parent Vessel ◽

3D Printed ◽

Wall Shear ◽

Dynamics Simulations

ObjectivesTo study the correlation between wall shear stress and endothelial cell expression in a patient-specific, three-dimensional (3D)-printed model of a cerebral aneurysm.Materials and methodsA 3D-printed model of a cerebral aneurysm was created from a patient’s angiogram. After populating the model with human endothelial cells, it was exposed to media under flow for 24 hours. Endothelial cell morphology was characterized in five regions of the 3D-printed model using confocal microscopy. Endothelial cells were then harvested from distinct regions of the 3D-printed model for mRNA collection and gene analysis via quantitative polymerase chain reaction (qPCR.) Cell morphology and mRNA measurement were correlated with computational fluid dynamics simulations.ResultsThe model was successfully populated with endothelial cells, which survived under flow for 24 hours. Endothelial morphology showed alignment with flow in the proximal and distal parent vessel and aneurysm neck, but disorganization in the aneurysm dome. Genetic analysis of endothelial mRNA expression in the aneurysm dome and distal parent vessel was compared with the proximal parent vessels. ADAMTS-1 and NOS3 were downregulated in the aneurysm dome, while GJA4 was upregulated in the distal parent vessel. Disorganized morphology and decreased ADAMTS-1 and NOS3 expression correlated with areas of substantially lower wall shear stress and wall shear stress gradient in computational fluid dynamics simulations.ConclusionsCreating 3D-printed models of patient-specific cerebral aneurysms populated with human endothelial cells is feasible. Analysis of these cells after exposure to flow demonstrates differences in both cell morphology and genetic expression, which correlate with areas of differential hemodynamic stress.

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Effects of a Short-Term Left Ventricular Assist Device on Hemodynamics in a Heart Failure Patient-Specific Aorta Model: A CFD Study

Frontiers in Physiology ◽

10.3389/fphys.2021.733464 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yu Wang ◽

Junwei Wang ◽

Jing Peng ◽

Mingming Huo ◽

Zhiqiang Yang ◽

...

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Pressure Difference ◽

Left Ventricular ◽

Patient Specific ◽

Short Term ◽

Ventricular Assist ◽

Left Ventricular Assist ◽

Wall Shear ◽

Hemodynamic Performance

Patients with heart failure (HF) or undergoing cardiogenic shock and percutaneous coronary intervention require short-term cardiac support. Short-term cardiac support using a left ventricular assist device (LVAD) alters the pressure and flows of the vasculature by enhancing perfusion and improving the hemodynamic performance for the HF patients. However, due to the position of the inflow and outflow of the LVAD, the local hemodynamics within the aorta is altered with the LVAD support. Specifically, blood velocity, wall shear stress, and pressure difference are altered within the aorta. In this study, computational fluid dynamics (CFD) was used to elucidate the effects of a short-term LVAD for hemodynamic performance in a patient-specific aorta model. The three-dimensional (3D) geometric models of a patient-specific aorta and a short-term LVAD, Impella CP, were created. Velocity, wall shear stress, and pressure difference in the patient-specific aorta model with the Impella CP assistance were calculated and compared with the baseline values of the aorta without Impella CP support. Impella CP support augmented cardiac output, blood velocity, wall shear stress, and pressure difference in the aorta. The proposed CFD study could analyze the quantitative changes in the important hemodynamic parameters while considering the effects of Impella CP, and provide a scientific basis for further predicting and assessing the effects of these hemodynamic signals on the aorta.

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