Pulsatile Flow in the Human Left Coronary Artery Bifurcation: Average Conditions

1996 ◽  
Vol 118 (1) ◽  
pp. 74-82 ◽  
Author(s):  
Xiaoyi He ◽  
David N. Ku
Keyword(s):  
Shear Stress ◽  
Coronary Artery ◽  
Wall Shear Stress ◽  
Coronary Arteries ◽  
Left Coronary Artery ◽  
Outer Wall ◽  
Oscillatory Behavior ◽  
Circumflex Artery ◽  
Wall Shear

The localization of atherosclerosis in the coronary arteries may be governed by local hemodynamic features. In this study, the pulsatile hemodynamics of the left coronary artery bifurcation was numerically simulated using the spectral element method for realistic in vivo anatomic and physiologic conditions. The velocity profiles were found to be skewed in both the left anterior descending and the circumflex coronary arteries. Velocity skewing arose from the bifurcation as well as from the curvature of the artery over the myocardial surface. Arterial wall shear stress was significantly lower in the bifurcation region, including the side walls. The greatest oscillatory behavior was localized to the outer wall of the circumflex artery. The time-averaged mean wall shear stress varied from about 3 to 98 dynes/cm2 in the left coronary artery system. The highly localized distribution of low and oscillatory shear stress along the walls strongly correlates with the focal locations of atheroma in the human left coronary artery.

Abstract 2800: Assessment of Computational Fluid Dynamics to Calculate Individual Coronary Wall Shear Stress In-Vivo

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Johannes Rieber ◽  
Thomas Redel ◽  
Holger Hetterich ◽  
Tobias Potzger ◽  
Konstantin Nikolaou ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Coronary Angiography ◽  
Wall Shear Stress ◽  
Radio Frequency ◽  
Intravascular Ultrasound ◽  
Coronary Arteries ◽  
Wall Shear

Beyond classic risk parameters non physiologic or oscillating wall shear stress (WSS) has been proven to act as a local factor for initiation and progression of atherosclerosis as well as for plaque rupture. Direct measurement of WSS in-vivo is difficult and restricted to animal models. Computational fluid dynamics (CFD) is a validated tool to compute flow parameters and WSS. For this purpose an exact model of the underlying patient specific geometry of the coronary tree is a prerequisite. Using 3D-IVUS or modern multislice computed tomographic coronary angiography (CTA) with submilimeter resolution these data can be provided. The aim of this study was to 1.) demonstrate feasibility of in-vivo CFD calculation of human coronaries based on CTA and 2.) to correlate the findings with radio frequency tissue information derived by intravascular ultrasound. We prospectively included 10 patients with suspected coronary artery disease who received CTA (Dual source 64 slice CT) and invasive conventional coronary angiography. Intravascular ultrasound and ECG-triggered radio frequency analysis (VH) was attempted in all three epicardial vessels. In the CTA-dataset the coronaries were segmented and a mesh model for CFD was generated. CFD calculations were performed using a commercial available software package with laminar flow and blood as a Newtonian fluid as boundary conditions. Coronary models were stationary with rigid vessel walls, while the pulsatile inflow characteristics was derived from invasive Doppler velocity measurement. Flow pattern calculations, vessel wall shear stress and IVUS analysis were successfully performed in 24/30 and 17/30 coronary arteries. The presence of high shear stress and non turbulent flow was inversely correlated with the presence of plaque as determined by intravascular ultrasound. No correlation of any CFD parameter with the radio frequency tissue information could yet be observed. The findings of the present study demonstrate the feasibility of assessing fluid tissue interactions in human coronary arteries using CTA and its correlation to invasive findings. The possible impact of CFD parameters on risk- and treatment stratification has to be determined in a large scale prospective trial.

scholarly journals Coronary CT angiography-based estimation of myocardial perfusion territories for coronary artery FFR and wall shear stress simulation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yu-Fang Hsieh ◽  
Chih-Kuo Lee ◽  
Weichung Wang ◽  
Yu-Cheng Huang ◽  
Wen-Jeng Lee ◽  
...  
Keyword(s):  
Shear Stress ◽  
Coronary Artery ◽  
Wall Shear Stress ◽  
Boundary Conditions ◽  
Mass Flow Rate ◽  
Coronary Arteries ◽  
Mass Flow ◽  
Flow Rate ◽  
Fractional Flow ◽  
Wall Shear

AbstractThis study aims to apply a CCTA-derived territory-based patient-specific estimation of boundary conditions for coronary artery fractional flow reserve (FFR) and wall shear stress (WSS) simulation. The non-invasive simulation can help diagnose the significance of coronary stenosis and the likelihood of myocardial ischemia. FFR is often regarded as the gold standard to evaluate the functional significance of stenosis in coronary arteries. In another aspect, proximal wall shear stress ($$\mathrm{{WSS}_{prox}}$$ WSS prox ) can also be an indicator of plaque vulnerability. During the simulation process, the mass flow rate of the blood in coronary arteries is one of the most important boundary conditions. This study utilized the myocardium territory to estimate and allocate the mass flow rate. 20 patients are included in this study. From the knowledge of anatomical information of coronary arteries and the myocardium, the territory-based FFR and the $$\mathrm{{WSS}_{prox}}$$ WSS prox can both be derived from fluid dynamics simulations. Applying the threshold of distinguishing between significant and non-significant stenosis, the territory-based method can reach the accuracy, sensitivity, and specificity of 0.88, 0.90, and 0.80, respectively. For significantly stenotic cases ($$\mathrm{FFR}_{m}$$ FFR m $$\le$$ ≤ 0.80), the vessels usually have higher wall shear stress in the proximal region of the lesion.

Influence of bifurcation angle in left coronary artery with stenosis: A CFD analysis

2020 ◽  
Vol 31 (6) ◽  
pp. 339-349
Author(s):  
Sarfaraz Kamangar ◽  
Irfan Anjum Badruddin ◽  
Ali E. Anqi ◽  
C. Ahamed Saleel ◽  
Vineet Tirth ◽  
...  
Keyword(s):  
Shear Stress ◽  
Coronary Artery ◽  
Wall Shear Stress ◽  
Left Coronary Artery ◽  
Computational Study ◽  
Flow Behavior ◽  
Recirculation Region ◽  
Hemodynamic Parameters ◽  
Bifurcation Angle ◽  
Wall Shear

BACKGROUND: The left coronary artery commonly known as LCA gets divided into two branches, such as the left circumflex (LCX) and left anterior descending (LAD) at a particular angle. This angle is varies from person to person. The present computational study contributes remarkable expertise about the influence of this angle variation on the hemodynamic parameters in the presence of 80% area stenosis at the LAD branch. OBJECTIVE: This study aimed to compare the effect of the bifurcation angle on hemodynamic parameters in the left coronary artery with 80% stenosis. METHOD: Computational models of left coronary bifurcation angles of 30°, 60°, 90°, 120° were developed to understand the flow behavior of left coronary artery branches. The 80% area stenosis (AS) is considered at the LAD branch immediate to bifurcation. RESULTS: Measurements of pressure, velocity and wall shear stress were carried out corresponding to various bifurcation angles. It was found that the drop-in pressure increases as the angle increases from narrow to wider. A slight elevation in the velocity at the stenosis was observed. In addition, the obtained results further reveal a recirculation region immediately after the plaque, which leads to more deposition of plaque in the flow obstructed area. It is known that the shear stress at the arterial wall across the stenosis increases as the angle of bifurcation increases from narrow to wider. CONCLUSIONS: The bifurcation of the left coronary artery and size of the stenosis have a notable impact on the pressure and wall shear stress. These two factors should be given due consideration by cardiologists to assess the complexity of stenosis in the LCA branches.

Non-Newtonian models for molecular viscosity and wall shear stress in a 3D reconstructed human left coronary artery

2008 ◽  
Vol 30 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Johannes V. Soulis ◽  
George D. Giannoglou ◽  
Yiannis S. Chatzizisis ◽  
Kypriani V. Seralidou ◽  
George E. Parcharidis ◽  
...  
Keyword(s):  
Shear Stress ◽  
Coronary Artery ◽  
Wall Shear Stress ◽  
Left Coronary Artery ◽  
Wall Shear ◽  
Molecular Viscosity
Sign in / Sign up

Export Citation Format

Share Document