Dataset Information

Effect of Wall Elasticity on Hemodynamics and Wall Shear Stress in Patient-Specific Simulations in the Coronary Arteries.

ABSTRACT: Wall shear stress (WSS) has been shown to be associated with myocardial infarction and progression of atherosclerosis. Wall elasticity is an important feature of hemodynamic modeling affecting WSS calculations. The objective of this study was to investigate the role of wall elasticity on WSS, and justify use of either rigid or elastic models in future studies. Digital anatomic models of the aorta and coronaries were created based on coronary computed tomography angiography (CCTA) in four patients. Hemodynamics were computed in rigid and elastic models using a finite element flow solver. WSS in five timepoints in the cardiac cycle and time averaged wall shear stress (TAWSS) were compared between the models at each 3mm subsegment and 4 arcs in cross sections along the centerlines of coronaries. In the left main, proximal left anterior descending, left circumflex and proximal right coronary artery of the elastic model, the mean percent radial increase were 5.95+/-1.25, 4.02+/-0.97, 4.08+/-0.94, 4.84+/-1.05%, respectively. WSS at each timepoint in the cardiac cycle had slightly different values, however when averaged over the cardiac cycle, there were negligible differences between the models. In both the subsegments (n=704) and sub-arc analysis, TAWSS in the two models were highly correlated (r=0.99) In investigation on the effect of coronary wall elasticity on WSS in CCTA-based models, the results of this study show no significant differences in TAWSS justifying using rigid wall models for future larger studies.

SUBMITTER: Eslami P

PROVIDER: S-EPMC7105147 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

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Effect of Wall Elasticity on Hemodynamics and Wall Shear Stress in Patient-Specific Simulations in the Coronary Arteries.

Eslami Parastou P Tran Justin J Jin Zexi Z Karady Julia J Sotoodeh Romina R Lu Michael T MT Hoffmann Udo U Marsden Alison A

Journal of biomechanical engineering 20200201 2

Wall shear stress (WSS) has been shown to be associated with myocardial infarction (MI) and progression of atherosclerosis. Wall elasticity is an important feature of hemodynamic modeling affecting WSS calculations. The objective of this study was to investigate the role of wall elasticity on WSS, and justify use of either rigid or elastic models in future studies. Digital anatomic models of the aorta and coronaries were created based on coronary computed tomography angiography (CCTA) in four pa ...[more]

PMID: 31074768

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Project description:AimsAtherosclerotic plaque development has been associated with wall shear stress (WSS). However, the multidirectionality of blood flow, and thus of WSS, is rarely taken into account. The purpose of this study was to comprehensively compare five metrics that describe (multidirectional) WSS behaviour and assess how WSS multidirectionality affects coronary plaque initiation and progression.Methods and resultsAdult familial hypercholesterolaemic pigs (n = 10) that were fed a high-fat diet, underwent imaging of the three main coronary arteries at three-time points [3 (T1), 9 (T2), and 10-12 (T3) months]. Three-dimensional geometry of the arterial lumen, in combination with local flow velocity measurements, was used to calculate WSS at T1 and T2. For analysis, arteries were divided into 3 mm/45° sectors (n = 3648). Changes in wall thickness and final plaque composition were assessed with near-infrared spectroscopy-intravascular ultrasound, optical coherence tomography imaging, and histology. Both in pigs with advanced and mild disease, the highest plaque progression rate was exclusively found at low time-averaged WSS (TAWSS) or high multidirectional WSS regions at both T1 and T2. However, the eventually largest plaque growth was located in regions with initial low TAWSS or high multidirectional WSS that, over time, became exposed to high TAWSS or low multidirectional WSS at T2. Besides plaque size, also the presence of vulnerable plaque components at the last time point was related to low and multidirectional WSS. Almost all WSS metrics had good predictive values for the development of plaque (47-50%) and advanced fibrous cap atheroma (FCA) development (59-61%).ConclusionThis study demonstrates that low and multidirectional WSS promote both initiation and progression of coronary atherosclerotic plaques. The high-predictive values of the multidirectional WSS metrics for FCA development indicate their potential as an additional clinical marker for the vulnerable disease.

Project description:BACKGROUND:Enhanced External Counterpulsation (EECP) can chronically relieve ischemic chest pain and improve the prognosis of coronary heart disease (CHD). Despite its role in mitigating heart complications, EECP and the mechanisms behind its therapeutic nature, such as its effects on blood flow hemodynamics, are still not fully understood. This study aims to elucidate the effect of EECP on significant hemodynamic parameters in the coronary arterial tree. METHODS:A finite volume method was used in conjunction with the inlet pressure wave (surrogated by the measured aortic pressure) before and during EECP and outlet flow resistance, assuming the blood as newtonian fluid. The time-average wall shear stress (TAWSS) and oscillatory shear index (OSI) were determined from the flow field. RESULTS:Regardless of the degree of vascular stenosis, hemodynamic conditions and flow patterns could be improved during EECP. In comparison with the original tree, the tree with a severe stenosis (75% area stenosis) demonstrated more significant improvement in hemodynamic conditions and flow patterns during EECP, with surface area ratio of TAWSS risk area (SAR-TAWSS) reduced from 12.3% to 6.7% (vs. SAR-TAWSS reduced from 7.2% to 5.6% in the original tree) and surface area ratio of OSI risk area (SAR-OSI) reduced from 6.8% to 2.5% (vs. SAR-OSI of both 0% before and during EECP in the original tree because of mild stenosis). Moreover, it was also shown that small ratio of diastolic pressure (D) and systolic pressure (S) (D/S) could only improve the hemodynamic condition mildly. The SAR-TAWSS reduction ratio significantly increased as D/S became larger. CONCLUSIONS:A key finding of the study was that the improvement of hemodynamic conditions along the LMCA trees during EECP became more significant with the increase of D/S and the severity degree of stenoses at the bifurcation site. These findings have important implications on EECP as adjuvant therapy before or after percutaneous coronary intervention (PCI) in patients with diffuse atherosclerosis.

Dataset Information

Effect of Wall Elasticity on Hemodynamics and Wall Shear Stress in Patient-Specific Simulations in the Coronary Arteries.

Publications

Effect of Wall Elasticity on Hemodynamics and Wall Shear Stress in Patient-Specific Simulations in the Coronary Arteries.

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