Numerical Analysis of Pulsatile Blood Flow in a Stented Human Coronary Artery with a Flow Divider

Dehlaghi, Vahab; Shadpoor, Mohammad Tafazoli; Najarian, Siamak

doi:10.3844/ajassp.2007.397.404

Cited by 5 publications

(4 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…where, The outflow boundary conditions were assumed to be zero pressure at the flow outlet and no slip conditions at the vessel wall. The dynamic viscosity of blood and its density were assumed to be 3.5×10 -3 Pa.s and 1050 kg/m 3 , respectively [19,20,21,22] . The blood velocity boundary conditions were obtained from phase contrast MRI scanning.…”

Section: Methodsmentioning

confidence: 99%

“…Although it is difficult to verify conclusively such relationships without suitable in vivo studies, CFD can provide an excellent research tool to help understand these underlying issues. CFD is being employed by several researchers to explore further the nature of flow stagnation patterns on stent strut shape and spacing [20,21,22,23,24] . These studies have confirmed that the flow stagnation patterns between stent struts depend most strongly on stent strut spacing and have demonstrated that vessel wall compliance has little effect on these flow patterns.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Stent Geometry on Phase Shift between Pressure and Flow Waveforms in Stented Human Coronary Artery

Dehlaghi¹,

Najarian²,

Tafazzoli-Shadpour³

2008

American J. of Applied Sciences

Self Cite

View full text Add to dashboard Cite

Shear stress is known to play a central role in restenosis formation and is sensitive to stent geometry. Alterations of the phase shift between pressure and flow waveform created by a different stents were studied to compare the hemodynamic effects of stent design properties on restenosis in stented human coronary artery. Blood pressure waveforms were computed in three different sites, pre-stent, middle of stented arterial segment, and post-stent regions using computational fluid dynamics. Blood flow was assumed as pulsatile, incompressible, and Newtonian flow. Rigid boundary conditions were assumed for all models. The governing Navier-Stokes equations were solved using commercial software package (Fluent V6.0.12). Stents were assumed with real structure and modeled using the commercial software package (Gambit, V2.0). The alterations of the phase shift between pressure and flow waveform created by a different stents were investigated in three major regions using commercial software package (Matlab, V7.0). It is concluded that stent geometry changes the phase shift between pressure and flow waveforms in stented human coronary artery, and wall shear stress between stent struts was sensitive to these variations. The results show that variation in the phase shift is sensitive to stent geometry

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Stent Geometry on Phase Shift between Pressure and Flow Waveforms in Stented Human Coronary Artery

Dehlaghi¹,

Najarian²,

Tafazzoli-Shadpour³

2008

American J. of Applied Sciences

Self Cite

View full text Add to dashboard Cite

show abstract

“…Atherosclerosis is a vascular disease that reduces arterial lumen size through plaque formation and arterial wall thickening. The pathological complications of atherosclerosis, namely Coronary Heart Disease (CHD) and stroke, remain the leading cause of mortality in the western world (Dehlaghi et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Utilization of Specific Index for Measuring the Association between Periodontal Conditions and Coronary Artery Disease

Nader¹,

Mehdizadeh²

2010

Current Research in Dentistry

View full text Add to dashboard Cite

Problem statement: There is increasing evidence that periodontal disease could play a role in the Progression of coronary heart disease although there are conflicting results about this association in the literature and the difference of used periodontal scoring systems among the studies might be a reason. The purpose of this study was to evaluate a specific scoring system Periodontal Index for Risk of Infectiousness (PIRI) in comparison with one of the classic periodontal indices Extent and Severity Index (ESI). Approach: A Total of 200 patients (100 candidate for bypass Surgery and 100 presumably healthy controls) were enrolled in this cross-sectional study age and sex matching were done for the two groups. PIRI and ESI were used to assess the periodontal status in both groups. Results: The average of attachment loss extent in CHD group was 94.77±13 and for severity: 4.47±1.36. The mean ESI scores was significantly higher in patients than in controls (p<0/0001) PIRI score showed that 87 patients in CHD group were in moderate group and 13 patients in severe group also PIRI scores between two groups, showed a significant difference (p = 0/01). A logistic regression model showed a association between both indices and coronary situation of patients. Conclusion: Our findings suggest that PIRI might be the best indicator for quantifying of subgingival surface exposure to microbial products and the risk of systemic consequences of periodontitis. Although it should be evaluated in other studies.

show abstract

“…The identification of relationships between geometric variables and hemodynamic patterns can be used to infer which mechanical factors are more likely to be involved in the localization of disease (Dehlaghi et al, 2007;2008a;2008b;Wellnhofer et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Wall Shear Stress Distribution in Patient Specific Coronary Artery Bifurcation

Dehlaghi¹

2010

American Journal of Applied Sciences

View full text Add to dashboard Cite

Problem statement: Atherogenesis is affected by hemodynamic parameters, such as wall shear stress and wall shear stress spatial gradient. These parameters are largely dependent on the geometry of arterial tree. Arterial bifurcations contain significant flow disturbances. Approach: The effects of branch angle and vessel diameter ratio at the bifurcations on the wall shear stress distribution in the coronary arterial tree based on CT images were studied. CT images were digitally processed to extract geometrical contours representing the coronary vessel walls. The lumen of the coronary arteries of the patients was segmented using the open source software package (VMTK). The resulting lumens of coronary arteries were fed into a commercial mesh generator (GAMBIT, Fluent Inc.) to generate a volume that was filled with tetrahedral elements. The FIDAP software (Fluent Corp.) was used to carry out the simulation by solving Navier-Stokes equations. The FIELDVIEW software (Version 10.0, Intelligent Light, Lyndhurst, NJ) was used for the visualization of flow patterns and the quantification of wall shear stress. Post processing was done with VMTK and MATLAB. A parabolic velocity profile was prescribed at the inlets and outlets, except for 1. Stress free outlet was assigned to the remaining outlet. Results: The results show that for angle lower than 90°, low shear stress regions are observed at the non-flow divider and the apex. For angle larger than 90°, low shear stress regions only at the nonflow divider. By increasing of diameter of side branch ratio, low shear stress regions in the side branch appear at the non-flow divider. Conclusion: It is concluded that not only angle and diameter are important, but also the overall 3D shape of the artery. More research is required to further quantify the effects angle and diameter on shear stress patterns in coronaries.

show abstract

Numerical Analysis of Pulsatile Blood Flow in a Stented Human Coronary Artery with a Flow Divider

Cited by 5 publications

References 24 publications

Effect of Stent Geometry on Phase Shift between Pressure and Flow Waveforms in Stented Human Coronary Artery

Effect of Stent Geometry on Phase Shift between Pressure and Flow Waveforms in Stented Human Coronary Artery

Utilization of Specific Index for Measuring the Association between Periodontal Conditions and Coronary Artery Disease

Wall Shear Stress Distribution in Patient Specific Coronary Artery Bifurcation

Contact Info

Product

Resources

About