Relative Blood Damage in the Three Phases of a Prosthetic Heart Valve Flow Cycle

Lamson, Theodore C.; Rosenberg, Gerson; Geselowitz, David B.; Deutsch, Steven; Stinebring, David R.; Frangos, John A.; Tarbell, John M.

doi:10.1097/00002480-199307000-00098

Cited by 21 publications

(29 citation statements)

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“…16,33 In addition, cavitation may cause hemolysis and thrombosis by damaging blood cells. 8,15,18 Despite the low incidence (<0.002%), this remains an important consideration during valve design. 14 Current literature has shown that these vapor bubbles occur on the inflow side of the valve during leaflet closure, lasting several hundred microseconds.…”

Section: Introductionmentioning

confidence: 99%

Cavitation Phenomena in Mechanical Heart Valves: Studied by Using a Physical Impinging Rod System

Chen

et al. 2010

Ann Biomed Eng

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When studying mechanical heart valve cavitation, a physical model allows direct flow field and pressure measurements that are difficult to perform with actual valves, as well as separate testing of water hammer and squeeze flow effects. Movable rods of 5 and 10 mm diameter impinged same-sized stationary rods to simulate squeeze flow. A 24 mm piston within a tube simulated water hammer. Adding a 5 mm stationary rod within the tube generated both effects simultaneously. Charged-coupled device (CCD) laser displacement sensors, strobe lighting technique, laser Doppler velocimetry (LDV), particle image velocimetry (PIV) and high fidelity piezoelectric pressure transducers measured impact velocities, cavitation images, squeeze flow velocities, vortices, and pressure changes at impact, respectively. The movable rods created cavitation at critical impact velocities of 1.6 and 1.2 m/s; squeeze flow velocities were 2.8 and 4.64 m/s. The isolated water hammer created cavitation at 1.3 m/s piston speed. The combined piston and stationary rod created cavitation at an impact speed of 0.9 m/s and squeeze flow of 3.2 m/s. These results show squeeze flow alone caused cavitation, notably at lower impact velocity as contact area increased. Water hammer alone also caused cavitation with faster displacement. Both effects together were additive. The pressure change at the vortex center was only 150 mmHg, which cannot generate the magnitude of pressure drop required for cavitation bubble formation. Cavitation occurred at 3-5 m/s squeeze flow, significantly different from the 14 m/s derived by Bernoulli's equation; the temporal acceleration of unsteady flow requires further study.

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Section: Introductionmentioning

confidence: 99%

Cavitation Phenomena in Mechanical Heart Valves: Studied by Using a Physical Impinging Rod System

Chen

et al. 2010

Ann Biomed Eng

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“…15 High stress, appreciable pressure change, or physical contact within these devices can cause damage to blood components due to turbulent effects as well as infection, anemia and secondary shear effects of immunosuppression, thrombosis, and bleeding. 15,17,21 Despite refinements in the design of artificial cardiac prostheses over the past 30 years, mechanical valve replacement has been associated with a variety of valve-related complications leading to serious disability or death. 13 Successful use of temporary cardiac assist devices also depends strongly on the degree of blood trauma experienced.…”

Section: Introductionmentioning

confidence: 99%

“…31 Biomedical researchers have previously characterized the blood damage potential of turbulent flows within prosthetic devices by using Reynolds stress levels. 21 However, Reynolds stresses in these studies have been indirectly extrapolated from multiple studies and do not provide sufficient information to directly quantify flow in the turbulent regime. 18,32 Turbulence is alternatively defined as a superposition of perturbations of eddies with different time, velocity, and length scales (collectively known as the Kolmogorov microscale).…”

Section: Introductionmentioning

confidence: 99%

“…23 Collectively, it appears that a study specifically evaluating the Kolmogorov microscale and its constituent values would provide a better physical understanding of the mechanism of blood damage by turbulence. 21 When shear stresses and velocity gradients are high, cell damage is especially relevant at the cell-fluid interface. When the membrane's threshold value is reached, the cell will lyse and release its contents into the plasma portion of blood.…”

Section: Introductionmentioning

confidence: 99%

“…When the membrane's threshold value is reached, the cell will lyse and release its contents into the plasma portion of blood. 21 Turbulent flow within cardiovascular prosthetic devices can cause cell damage due to shear stress when the uniaxial or biaxial membrane strain of the cell exceeds threshold values. 43 We theorize that eddy induced shear forces may cause cell surface area reduction via the cumulative outcomes of membrane viscoplastic flow effects, reduced proteinprotein stability of the cytoskeletal membrane, and accumulated membrane damage as these effects are carried out over time.…”

Section: Introductionmentioning

confidence: 99%

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The Cumulative and Sublethal Effects of Turbulence on Erythrocytes in a Stirred-Tank Model

et al. 2007

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Mechanical forces generated by prosthetic heart devices (artificial valves, artificial hearts, ventricular assist devices) have been known to cause damage and destruction of erythrocytes. Turbulent flow within such devices generates shear stresses and can induce cell damage. Current models of cell damage rate utilize only the power input per unit mass as a modeling parameter. A stirred-tank reactor provides for a more extensive characterization of turbulence through eddy scale calculations. Through a simplified model, turbulence can be characterized by evaluating the Kolmogorov microscale. Our analysis of erythrocyte rupture in a stirred tank reactor suggests that parameters such as eddy wavelength and eddy velocity may better characterize and model the turbulent damage. Further, hemolysis of red blood cells by turbulent effects has been shown to have a fixed rate for constant levels of power input. Damage inflicted on the remaining, intact erythrocytes (sublethal damage) was evaluated by exposure to turbulence followed by osmotic fragility (OF) testing. Logistic models were fit to the OF data indicating a significant osmotic sensitivity in the sublethal damaged population between control and turbulence-exposed cells (chi(2) test; p < 0.001). This susceptibility indicates a significant cell population more susceptible to destruction as a result of turbulent exposure. This work has therefore helped identify optimization parameters for evaluating cell damage potential when engineering cardiovascular prosthetic devices.

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Simulation of the Three-Dimensional Hinge Flow Fields of a Bileaflet Mechanical Heart Valve Under Aortic Conditions

Simon

Sotiropoulos

et al. 2009

Ann Biomed Eng

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Thromboembolic complications of bileaflet mechanical heart valves (BMHV) are believed to be due to detrimental stresses imposed on blood elements by the hinge flows. Characterization of these flows is thus crucial to identify the underlying causes for complications. In this study, we conduct three-dimensional pulsatile flow simulations through the hinge of a BMHV under aortic conditions. Hinge and leaflet geometries are reconstructed from the Micro-Computed Tomography scans of a BMHV. Simulations are conducted using a Cartesian sharp-interface immersed-boundary methodology combined with a second-order accurate fractional-step method. Physiologic flow boundary conditions and leaflet motion are extracted from the Fluid–Structure Interaction simulations of the bulk of the flow through a BMHV. Calculations reveal the presence, throughout the cardiac cycle, of flow patterns known to be detrimental to blood elements. Flow fields are characterized by: (1) complex systolic flows, with rotating structures and slow reverse flow pattern, and (2) two strong diastolic leakage jets accompanied by fast reverse flow at the hinge bottom. Elevated shear stresses, up to 1920 dyn/cm2 during systole and 6115 dyn/cm2 during diastole, are reported. This study underscores the need to conduct three-dimensional simulations throughout the cardiac cycle to fully characterize the complexity and thromboembolic potential of the hinge flows.

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Relative Blood Damage in the Three Phases of a Prosthetic Heart Valve Flow Cycle

Cited by 21 publications

References 0 publications

Cavitation Phenomena in Mechanical Heart Valves: Studied by Using a Physical Impinging Rod System

Cavitation Phenomena in Mechanical Heart Valves: Studied by Using a Physical Impinging Rod System

The Cumulative and Sublethal Effects of Turbulence on Erythrocytes in a Stirred-Tank Model

Simulation of the Three-Dimensional Hinge Flow Fields of a Bileaflet Mechanical Heart Valve Under Aortic Conditions

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