The influence of multi-stenosis in the left coronary artery subjected to the variable blood flow rate

PurposeCoronary artery disease (CAD) is reported as one of the most common sources of death all over the world. The presence of stenosis (plaque) in the coronary arteries results in the restriction of blood supply, leading to myocardial infarction. The current study investigates the influence of multi stenosis on hemodynamic properties in a patient-specific left coronary artery.Design/methodology/approachA three-dimensional model of the patient-specific left coronary artery was reconstructed based on computed tomography (CT) scan images using MIMICS-20 software. The diseased model of the left coronary artery was investigated, having the narrowing of 90% and 70% of area stenosis (AS) at the left anterior descending (LAD) and left circumflex (LCX), respectively.FindingsThe results indicate that the upstream region of stenosis experiences very high pressure for 90% AS during the systolic period of the cardiac cycle. The pressure drops maximum as the flow travels into the stenotic zone, and the high flow velocities were observed across the 90% AS. The higher wall shear stresses occur at the stenosis region, and it increases with the increase in the flow rate. It is found that the maximum wall shear stress across 90% AS is at the highest risk for rupture. A recirculation region immediately after the stenosis results in the further development of stenosis.Originality/valueThe current study provides evidence that there is a strong effect of multi-stenosis on the blood flow in the left coronary artery.

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The Influence of Non-Newtonian Model on Properties of Blood Flow Through a Left Coronary Artery with Presence of Different Double Stenosis

International Journal of Heat and Technology ◽

10.18280/ijht.390324 ◽

2021 ◽

Vol 39 (3) ◽

pp. 895-905

Author(s):

Saleem K. Kadhim ◽

Mohammed G. Al-Azawy ◽

Sinan Abdul-Ghafar Ali ◽

Mina Qays Kadhim

Keyword(s):

Blood Flow ◽

Coronary Artery ◽

Left Coronary Artery ◽

Calculated Data ◽

Shear Stresses ◽

Numerical Investigations ◽

Newtonian Model ◽

Flow Through ◽

Wall Shear ◽

Flow States

Cardiovascular diseases were the main cause for loosing lives in the last decades due to the restricted blood flow states in the blood vessels areas. Numerical investigations have been conducted as the aim of this work to examine the blood flow, and wall shear stresses adjacent to the mono stenosis up to different degrees involved in the main, side and distal main branches as well as observe the pulsatile flow of blood in the left coronary artery through various percentage of stenosis. Both the Carreau non-Newtonian rheological model and the Newtonian model were utilized to model the blood fluid and wall shear stresses of left coronary artery, in a row, all the calculated data were validated with the previously published papers. It was found that the blood flow inside areas of the artery lie within the range of non-Newtonian rheological effects can be present, verifying the need to treat blood as non-Newtonian fluid; especially, with the case of 90% blockage.

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Numerical Simulation of Dispersed Particle-Blood Flow in the Stenosed Coronary Arteries

International Journal of Differential Equations ◽

10.1155/2018/2593425 ◽

2018 ◽

Vol 2018 ◽

pp. 1-16 ◽

Cited By ~ 2

Author(s):

Mongkol Kaewbumrung ◽

Somsak Orankitjaroen ◽

Pichit Boonkrong ◽

Buraskorn Nuntadilok ◽

Benchawan Wiwatanapataphee

Keyword(s):

Numerical Simulation ◽

Blood Flow ◽

Shear Stress ◽

Coronary Artery ◽

Pressure Drop ◽

Wall Shear Stress ◽

Stokes Equations ◽

Spherical Shape ◽

Shear Stresses ◽

Wall Shear

A mathematical model of dispersed bioparticle-blood flow through the stenosed coronary artery under the pulsatile boundary conditions is proposed. Blood is assumed to be an incompressible non-Newtonian fluid and its flow is considered as turbulence described by the Reynolds-averaged Navier-Stokes equations. Bioparticles are assumed to be spherical shape with the same density as blood, and their translation and rotational motions are governed by Newtonian equations. Impact of particle movement on the blood velocity, the pressure distribution, and the wall shear stress distribution in three different severity degrees of stenosis including 25%, 50%, and 75% are investigated through the numerical simulation using ANSYS 18.2. Increasing degree of stenosis severity results in higher values of the pressure drop and wall shear stresses. The higher level of bioparticle motion directly varies with the pressure drop and wall shear stress. The area of coronary artery with higher density of bioparticles also presents the higher wall shear stress.

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Investigation of two-way fluid-structure interaction of blood flow in a patient-specific left coronary artery

Bio-Medical Materials and Engineering ◽

10.3233/bme-201171 ◽

2021 ◽

pp. 1-18

Author(s):

Abdulgaphur Athani ◽

N.N.N. Ghazali ◽

Irfan Anjum Badruddin ◽

Sarfaraz Kamangar ◽

Ali E. Anqi ◽

...

Keyword(s):

Blood Flow ◽

Shear Stress ◽

Coronary Artery ◽

Wall Shear Stress ◽

Left Coronary Artery ◽

Fluid Structure Interaction ◽

Patient Specific ◽

Hemodynamic Parameters ◽

Fluid Structure ◽

Structure Interaction

BACKGROUND: The blood flow in the human artery has been a subject of sincere interest due to its prime importance linked with human health. The hemodynamic study has revealed an essential aspect of blood flow that eventually proved to be paramount to make a correct decision to treat patients suffering from cardiac disease. OBJECTIVE: The current study aims to elucidate the two-way fluid-structure interaction (FSI) analysis of the blood flow and the effect of stenosis on hemodynamic parameters. METHODS: A patient-specific 3D model of the left coronary artery was constructed based on computed tomography (CT) images. The blood is assumed to be incompressible, homogenous, and behaves as Non-Newtonian, while the artery is considered as a nonlinear elastic, anisotropic, and incompressible material. Pulsatile flow conditions were applied at the boundary. Two-way coupled FSI modeling approach was used between fluid and solid domain. The hemodynamic parameters such as the pressure, velocity streamline, and wall shear stress were analyzed in the fluid domain and the solid domain deformation. RESULTS: The simulated results reveal that pressure drop exists in the vicinity of stenosis and a recirculation region after the stenosis. It was noted that stenosis leads to high wall stress. The results also demonstrate an overestimation of wall shear stress and velocity in the rigid wall CFD model compared to the FSI model.

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Two-Phase Non-Newtonian Pulsatile Blood Flow Simulations in a Rigid and Flexible Patient-Specific Left Coronary Artery (LCA) Exhibiting Multi-Stenosis

Applied Sciences ◽

10.3390/app112311361 ◽

2021 ◽

Vol 11 (23) ◽

pp. 11361

Author(s):

Abdulgaphur Athani ◽

Nik Nazri Nik Ghazali ◽

Irfan Anjum Badruddin ◽

Abdullah Y. Usmani ◽

Sarfaraz Kamangar ◽

...

Keyword(s):

Blood Flow ◽

Coronary Artery ◽

Left Coronary Artery ◽

Solid Wall ◽

Three Dimensional ◽

Patient Specific ◽

Maximum Pressure ◽

Three Dimensional Model ◽

Two Phase ◽

Pressure Drops

Coronary artery disease (CAD) is stated as one of the most common causes of death all over the world. This article explores the influence of multi stenosis in a flexible and rigid left coronary artery (LCA) model using a multiphase blood flow system which has not yet been studied. Two-way fluid–solid interaction (FSI) is employed to achieve flow within the flexible artery model. A realistic three-dimensional model of multi-stenosed LCA was reconstructed based on computerized tomography (CT) images. The fluid domain was solved using a finite volume-based commercial software (FLUENT 2020). The fluid (blood) and solid (wall) domains were fully coupled by using the ANSYS Fluid-Structure Interaction solver. The maximum pressure drops, and wall shear stress was determined across the sever stenosis (90% AS). The higher region of displacement occurs at the pre-stenosis area compared to the other area of the left coronary artery model. An increase in blood flow velocity across the restricted regions (stenosis) in the LCA was observed, whereas the recirculation zone at the post-stenosis and bifurcation regions was noted. An overestimation of hemodynamic descriptors for the rigid models was found as compared to the FSI models.

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Blood Flow Manipulation in the Aorta With Coarctation and Arch Narrowing for Pediatric Subjects

Journal of Applied Mechanics ◽

10.1115/1.4048570 ◽

2020 ◽

Vol 88 (2) ◽

Author(s):

Yuxi Jia ◽

Kumaradevan Punithakumar ◽

Michelle Noga ◽

Arman Hemmati

Keyword(s):

Blood Pressure ◽

Blood Flow ◽

Shear Stress ◽

Wall Shear Stress ◽

Aortic Arch ◽

Flow Direction ◽

Upper Body ◽

Patient Specific ◽

Shear Stresses ◽

Wall Shear

Abstract The characteristics of blood flow in an abnormal pediatric aorta with an aortic coarctation and aortic arch narrowing are examined using direct numerical simulations and patient-specific boundary conditions. The blood flow simulations of a normal pediatric aorta are used for comparison to identify unique flow features resulting from the aorta geometrical anomalies. Despite flow similarities compared to the flow in normal aortic arch, the flow velocity decreases with an increase in pressure, wall shear stress, and vorticity around both anomalies. The presence of wall shear stresses in the trailing indentation region and aorta coarctation opposing the primary flow direction suggests that there exist recirculation zones in the aorta. The discrepancy in relative flowrates through the top and bottom of the aorta outlets, and the pressure drop across the coarctation, implies a high blood pressure in the upper body and a low blood pressure in the lower body. We propose using flow manipulators prior to the aortic arch and coarctation to lower the wall shear stress, while making the recirculation regions both smaller and weaker. The flow manipulators form a guide to divert and correct blood flow in critical regions of the aorta with anomalies.

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Integrating Patient-Specific Electrocardiogram Signals and Image-Based Computational Fluid Dynamics Method to Analyze Coronary Blood Flow in Patients during Cardiac Arrhythmias

Journal of Medical and Biological Engineering ◽

10.1007/s40846-019-00504-8 ◽

2019 ◽

Vol 40 (2) ◽

pp. 264-272

Author(s):

Szu-Hsien Chou ◽

Kuan-Yu Lin ◽

Zhen-Ye Chen ◽

Chun-Jung Juan ◽

Chien-Yi Ho ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Blood Flow ◽

Coronary Artery ◽

Cardiac Arrhythmia ◽

Coronary Arteries ◽

Flow Rate ◽

Blood Flow Rate ◽

Patient Specific ◽

Ecg Signals

Abstract Purpose The aim of this study was to use the computational fluid dynamics (CFD) method, patient-specific electrocardiogram (ECG) signals, and computed tomography three-dimensional image reconstruction technique to investigate the blood flow in coronary arteries during cardiac arrhythmia. Methods Two patients with premature ventricular contraction-type cardiac arrhythmia and one with atrial fibrillation-type cardiac arrhythmia were investigated. The inlet velocity of the coronary artery in simulation was applied with the measured velocity profile of the left ventricular outflow tract (LVOT) from the Doppler echocardiography. The measured patient central aortic blood pressure waveform was employed for the coronary artery outlet in simulation. The no-slip boundary condition was applied to the arterial wall. Results For the patient with irregular cardiac rhythms (Case I), the coronary blood flow rate under the shortened and lengthened cardiac rhythms were 0.66 and 0.96 mL/s, respectively. In Case II, the maximum velocity at the LVOT under a normal heartbeat was found to be 101 cm/s, whereas the average value was 73 cm/s. In Case III, the patient was also diagnosed with a congenital stenosis problem at the myocardial bridge (MCB) at the LAD. The measured blood flow rate at the MCB of the LAD for the three heartbeats in Case III was found to be 0.68, 1.08, and 1.14 mL/s. Conclusion The integration of patient-specific ECG signals and image-based CFD methods can clearly analyze hemodynamic information for patients during cardiac arrhythmia. The cardiac arrhythmia can reduce the blood flow in the coronary arteries.

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The Wall Shear Stress of a Pulsatile Blood Flow in a Patient Specific Stenotic Right Coronary Artery

Engineering ◽

10.4236/eng.2013.510b080 ◽

2013 ◽

Vol 05 (10) ◽

pp. 396-399 ◽

Cited By ~ 1

Author(s):

Biyue Liu

Keyword(s):

Blood Flow ◽

Shear Stress ◽

Coronary Artery ◽

Wall Shear Stress ◽

Right Coronary Artery ◽

Patient Specific ◽

Pulsatile Blood Flow ◽

Wall Shear

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Human fetal hearts with tetralogy of Fallot have altered fluid dynamics and forces

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00235.2018 ◽

2018 ◽

Vol 315 (6) ◽

pp. H1649-H1659 ◽

Cited By ~ 6

Author(s):

Hadi Wiputra ◽

Ching Kit Chen ◽

Elias Talbi ◽

Guat Ling Lim ◽

Sanah Merchant Soomar ◽

...

Keyword(s):

Blood Flow ◽

Tetralogy Of Fallot ◽

Congenital Heart ◽

Elevated Pressure ◽

Patient Specific ◽

Shear Stresses ◽

Additional Energy ◽

Congenital Heart Malformations ◽

Wall Shear ◽

Heart Malformations

Studies have suggested the effect of blood flow forces in pathogenesis and progression of some congenital heart malformations. It is therefore of interest to study the fluid mechanic environment of the malformed prenatal heart, such as the tetralogy of Fallot (TOF), especially when little is known about fetal TOF. In this study, we performed patient-specific ultrasound-based flow simulations of three TOF and seven normal human fetal hearts. TOF right ventricles (RVs) had smaller end-diastolic volumes (EDVs) but similar stroke volumes (SVs), whereas TOF left ventricles (LVs) had similar EDVs but slightly increased SVs compared with normal ventricles. Simulations showed that TOF ventricles had elevated systolic intraventricular pressure gradient (IVPG) and required additional energy for ejection but IVPG elevations were considered to be mild relative to arterial pressure. TOF RVs and LVs had similar pressures because of equalization via ventricular septal defect (VSD). Furthermore, relative to normal, TOF RVs had increased diastolic wall shear stresses (WSS) but TOF LVs were not. This was caused by high tricuspid inflow that exceeded RV SV, leading to right-to-left shunting and chaotic flow with enhanced vorticity interaction with the wall to elevate WSS. Two of the three TOF RVs but none of the LVs had increased thickness. As pressure elevations were mild, we hypothesized that pressure and WSS elevation could play a role in the RV thickening, among other causative factors. Finally, the endocardium surrounding the VSD consistently experienced high WSS because of RV-to-LV flow shunt and high flow rate through the over-riding aorta. NEW & NOTEWORTHY Blood flow forces are thought to cause congenital heart malformations and influence disease progression. We performed novel investigations of intracardiac fluid mechanics of tetralogy of Fallot (TOF) human fetal hearts and found essential differences from normal hearts. The TOF right ventricle (RV) and left ventricle had similar and elevated pressure but only the TOF RV had elevated wall shear stress because of elevated tricuspid inflow, and this may contribute to the observed RV thickening. TOF hearts also expended more energy for ejection.

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

Bio-Medical Materials and Engineering ◽

10.3233/bme-201107 ◽

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.

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