Two-dimensional color-mapping of turbulent shear stress distribution downstream of two aortic bioprosthetic valves in vitro

Nygaard, Hans; Giersiepen, M; Hasenkam, J. Michael; Reul, H.; Paulsen, Peter Kildeberg; Rovsing, Poul E.; Westphal, D.

doi:10.1016/0021-9290(92)90262-y

Cited by 37 publications

(19 citation statements)

References 21 publications

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“…The results showed that damage to RBCs and platelets were due to Reynolds shear stress in turbulence. 14,18,31,36 However, more recent research may indicate otherwise. Grigioni et al 15 pointed out that the Index of Hemolysis would increase with Reynolds shear stress in the experiment by Sallam, 35 thus indicating there was some contribution by Reynolds shear stress.…”

Section: Introductionmentioning

confidence: 87%

Estimation of Viscous Dissipative Stresses Induced by a Mechanical Heart Valve Using PIV Data

2009

Ann Biomed Eng

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Among the clinical complications of mechanical heart valves (MHVs), hemolysis was previously thought to result from Reynolds stresses in turbulent flows. A more recent hypothesis suggests viscous dissipative stresses at spatial scales similar in size to red blood cells may be related to hemolysis in MHVs, but the resolution of current instrumentation is insufficient to measure the smallest eddy sizes. We studied the St. Jude Medical (SJM) 27 mm valve in the aortic position of a pulsatile circulatory mock loop under physiologic conditions with particle image velocimetry (PIV). Assuming a dynamic equilibrium assumption between the resolved and sub-grid-scale (SGS) energy flux, the SGS energy flux was calculated from the strain rate tensor computed from the resolved velocity fields and the SGS stress was determined by the Smagorinsky model, from which the turbulence dissipation rate and then the viscous dissipative stresses were estimated. Our results showed Reynolds stresses up to 80 N/m2 throughout the cardiac cycle, and viscous dissipative stresses below 12 N/m2. The viscous dissipative stresses remain far below the threshold of red blood cell hemolysis, but could potentially damage platelets, implying the need for further study in the phenomenon of MHV hemolytic complications.

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Section: Introductionmentioning

confidence: 87%

Estimation of Viscous Dissipative Stresses Induced by a Mechanical Heart Valve Using PIV Data

2009

Ann Biomed Eng

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“…Researchers have extensively explored the causes of hemolysis induced by mechanical heart valves (MHVs) through flow visualization tools such as particle image velocimetry, Doppler ultrasound, and hot‐film anemometry (6,14–17). The results of these studies confirmed the hemolysis outcomes observed during MHV clinical use and identified the hinge region as the most prominent contributor to cell damage.…”

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confidence: 87%

Computational Evaluation of Platelet Activation Induced by a Bioprosthetic Heart Valve

Sirois

Sun

2010

Artificial Organs

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It is known that bioprosthetic heart valves (BHVs) have better hemodynamics and lower thromboembolic events compared with their mechanical counterparts; however, patients implanted with BHVs still face the potential of such complications. The risk of a clinical thromboembolism is on average 0.7% per year in patients with tissue valves in sinus rhythm. In this study, we developed a computational fluid dynamic (CFD) model of a BHV implanted in an aortic root and investigated the BHV-induced platelet activation using a damage accumulation model previously applied to mechanical valves. The CFD model was validated against published experimental data, including the flow velocity profile across the valve and the transvalvular pressure drop, and close matches were obtained. Hemodynamic performance measures such as flow velocity, turbulent kinetic energy, and wall shear stress were explored. Lagrangian particle tracking was used to calculate the extent of platelet activation for central bulk flow and flow in the vicinity of the leaflets. A peak flow of 2.22 m/s was observed at 40 msec after peak systole in the vicinity of a fold at the base of the leaflets. With the platelet activation expressed as 0-100% of activation threshold levels, mean damage on one pass was 2.489 × 10(-7)% and maximum damage on one pass was 8.778 × 10(-4)%. Our results suggested that the potential for BHV-induced platelet activation was low and that the leaflet's fully open geometry might play a role in the extent of blood element damage.

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“…Reynolds shear stresses (turbulent stresses have been correlated in literature with hemolysis and platelet activation [19,21,[44][45][46]. Turbulent non-physiological flow (that happens due to valve deterioration) was connected with blood damage, such as platelet activation, thrombus formation and hemolysis [47][48][49][50][51]. In-vitro studies investigated the risk of platelet activation highlighting 10 to 100 Pa as the beginning of platelet activation [52].…”

Section: Comparison Between Idealized and Anatomical Sinus Geometriesmentioning

confidence: 99%

Sinus Hemodynamics in Representative Stenotic Native Bicuspid and Tricuspid Aortic Valves: An In-Vitro Study

Hatoum

Dasi

2018

Fluids

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(1) The study’s objective is to assess sinus hemodynamics differences between stenotic native bicuspid aortic valve (BAV) and native tricuspid aortic valve (TrAV) sinuses in order to assess sinus flow shear and vorticity dynamics in these common pathological states of the aortic valve. (2) Representative patient-specific aortic roots with BAV and TrAV were selected, segmented, and 3D printed. The flow dynamics within the sinus were assessed in-vitro using particle image velocimetry in a left heart simulator at physiological pressure and flow conditions. Hemodynamic data calculations, vortex tracking, shear stress probability density functions and sinus washout calculations based on Lagrangian particle tracking were performed. (3) (a) At peak systole, velocity and vorticity in BAV reach 0.67 ± 0.02 m/s and 374 ± 5 s−1 versus 0.49 ± 0.03 m/s and 293 ± 3 s−1 in TrAV; (b) Aortic sinus vortex is slower to form but conserved in BAV sinus; (c) BAV shear stresses exceed those of TrAV (1.05 Pa versus 0.8 Pa); (d) Complete TrAV washout was achieved after 1.5 cycles while it was not for BAV. 4) In conclusion, sinus hemodynamics dependence on the different native aortic valve types and sinus morphologies was clearly highlighted in this study.

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Two-dimensional color-mapping of turbulent shear stress distribution downstream of two aortic bioprosthetic valves in vitro

Cited by 37 publications

References 21 publications

Estimation of Viscous Dissipative Stresses Induced by a Mechanical Heart Valve Using PIV Data

Estimation of Viscous Dissipative Stresses Induced by a Mechanical Heart Valve Using PIV Data

Computational Evaluation of Platelet Activation Induced by a Bioprosthetic Heart Valve

Sinus Hemodynamics in Representative Stenotic Native Bicuspid and Tricuspid Aortic Valves: An In-Vitro Study

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