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Article

Fluid Flow Characteristics of Healthy and Calcified Aortic Valves Using Three-Dimensional Lagrangian Coherent Structures Analysis

1
Biomedical Research Center, Qatar University, Doha P.O. Box 2713, Qatar
2
Department of Mechanical Engineering, TOBB University of Economics and Technology, 06560 Ankara, Turkey
3
Department of Biomedical Sciences, College of Health Science-QU Health, Qatar University, Doha P.O. Box 2713, Qatar
4
Department of Mechanical Engineering, Faculty of Engineering, Yeditepe University, Kayisdagi Cad., 34755 Istanbul, Turkey
*
Authors to whom correspondence should be addressed.
Contributed equally to this work.
Academic Editors: Fang-Bao Tian and Li Wang
Fluids 2021, 6(6), 203; https://doi.org/10.3390/fluids6060203
Received: 19 April 2021 / Revised: 9 May 2021 / Accepted: 21 May 2021 / Published: 31 May 2021
(This article belongs to the Special Issue Computational Biofluid Mechanics)
Aortic valve calcification is an important cardiovascular disorder that deteriorates the accurate functioning of the valve leaflets. The increasing stiffness due to the calcification prevents the complete closure of the valve and therefore leads to significant hemodynamic alterations. Computational fluid dynamics (CFD) modeling enables the investigation of the entire flow domain by processing medical images from aortic valve patients. In this study, we computationally modeled and simulated a 3D aortic valve using patient-specific dimensions of the aortic root and aortic sinus. Leaflet stiffness is deteriorated in aortic valve disease due to calcification. In order to investigate the influence of leaflet calcification on flow dynamics, three different leaflet-stiffness values were considered for healthy, mildly calcified, and severely calcified leaflets. Time-dependent CFD results were used for applying the Lagrangian coherent structures (LCS) technique by performing finite-time Lyapunov exponent (FTLE) computations along with Lagrangian particle residence time (PRT) analysis to identify unique vortex structures at the front and backside of the leaflets. Obtained results indicated that the peak flow velocity at the valve orifice increased with the calcification rate. For the healthy aortic valve, a low-pressure field was observed at the leaflet tips. This low-pressure field gradually expanded through the entire aortic sinus as the calcification level increased. FTLE field plots of the healthy and calcified valves showed a variety of differences in terms of flow structures. When the number of fluid particles in the healthy valve model was taken as reference, 1.59 and 1.74 times more particles accumulated in the mildly and severely calcified valves, respectively, indicating that the calcified valves were not sufficiently opened to allow normal mass flow rates. View Full-Text
Keywords: Lagrangian coherent structures; aortic valve; calcification; hemodynamics; finite-time Lyapunov exponent; particle residence time; fluid–structure interaction Lagrangian coherent structures; aortic valve; calcification; hemodynamics; finite-time Lyapunov exponent; particle residence time; fluid–structure interaction
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MDPI and ACS Style

Mutlu, O.; Salman, H.E.; Yalcin, H.C.; Olcay, A.B. Fluid Flow Characteristics of Healthy and Calcified Aortic Valves Using Three-Dimensional Lagrangian Coherent Structures Analysis. Fluids 2021, 6, 203. https://doi.org/10.3390/fluids6060203

AMA Style

Mutlu O, Salman HE, Yalcin HC, Olcay AB. Fluid Flow Characteristics of Healthy and Calcified Aortic Valves Using Three-Dimensional Lagrangian Coherent Structures Analysis. Fluids. 2021; 6(6):203. https://doi.org/10.3390/fluids6060203

Chicago/Turabian Style

Mutlu, Onur, Huseyin E. Salman, Huseyin C. Yalcin, and Ali B. Olcay 2021. "Fluid Flow Characteristics of Healthy and Calcified Aortic Valves Using Three-Dimensional Lagrangian Coherent Structures Analysis" Fluids 6, no. 6: 203. https://doi.org/10.3390/fluids6060203

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