Relative blood damage index of the jellyfish valve and the Bjork-Shiley tilting-disk valve

Morsi, Yos S.; Kogure, Masahisa; Umezu, Mitsuo

doi:10.1007/bf02480061

Cited by 11 publications

(8 citation statements)

References 15 publications

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“…RBC are exposed to varying mechanical stresses throughout their traverse of the circulation without any mechanical damage. However, RBC undergo extremely high SS (>100 Pa) for a short period of time (<1 s) in artificial circulatory systems (e.g., heart-lung machines), which can cause both sub-hemolytic and hemolytic damage [26]. Hemolytic damage depends on magnitude of SS and duration, with the stress threshold for human RBC reported to be 300 Pa when exposed for less than one second [17,28].…”

Section: Introductionmentioning

confidence: 99%

Erythrocyte deformability responses to intermittent and continuous subhemolytic shear stress

et al. 2014

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BACKGROUND: Previous studies have demonstrated that red blood cells (RBC) either lyse or at least experience mechanical damage following prolonged exposure to high shear stress ( 100 Pa). Conversely, prolonged shear stress exposure within the physiological range (5-20 Pa, 300 s) was recently reported to improve RBC deformability. This study investigated the relationships between shear stress and RBC deformability to determine the breakpoint between beneficial vs. detrimental exposure to shear stress (i.e., "subhemolytic threshold"). A second aim of the study was to determine whether the frequency of intermittent application of shear stress influenced the subhemolytic threshold. METHODS: RBC were exposed to various levels of shear stress (0-100 Pa) in a Couette type shearing system for 300 s. RBC deformability was then immediately measured via ektacytometry. Parallel experiments were conducted at the same shear stresses, except the application time differed while keeping constant the total exposure time: shear stress was applied either for 30 s and repeated 10 times (10 × 30 s) or applied for 15 s and repeated 20 times (20 × 15 s). RESULTS: For a range of donors, the subhemolytic threshold with constant shear stress application was between 30-40 Pa. When physiological shear stress was applied in an intermittent manner, more frequent applications tended to improve (i.e., increase) RBC deformability. However, when supra-physiological shear stress was applied, both continuous and intermittent protocols damaged RBC. Changes of RBC mechanical behavior occurred without increases of hemoglobin in the suspending media, thus attesting to the absence of hemolysis. CONCLUSION: Shear stress has a biphasic effect on the mechanical properties of RBC, with the duration and rate of exposure appearing to have minimal impact on the subhemolytic threshold when compared with the magnitude of applied shear stress.

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Section: Introductionmentioning

confidence: 99%

Erythrocyte deformability responses to intermittent and continuous subhemolytic shear stress

et al. 2014

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“…The fluid‐induced mechanical stresses through these devices are often nonphysiological and elevated. For example, the blood through ventricular assist devices (VADs) and artificial heart valves can be exposed to very high shear stress (>100 Pa) for a short period of time (<1 s) . For VADs, high shear stresses located at or near the rotating tips lead to blood damage .…”

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confidence: 99%

Shear-Induced Hemolysis: Species Differences

et al. 2015

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The nonphysiological mechanical shear stress in blood-contacting medical devices is one major factor to device-induced blood damage. Animal blood is often used to test device-induced blood damage potential of these devices due to its easy accessibility and low cost. However, the differences in shear-induced blood damage between animals and human have not been well characterized. The purpose of this study was to investigate shear-induced hemolysis of human and three commonly used preclinical evaluation animal species (ovine, porcine, and bovine) under shear conditions encountered in blood-contacting medical devices. Shear-induced hemolysis experiments were conducted using two single-pass blood-shearing devices. Driven by an externally pressurized reservoir, blood single-passes through a small annular gap in the shearing devices where the blood was exposed to a uniform high shear stress. Shear-induced hemolysis at different conditions of exposure time (0.04 to 1.5 s) and shear stress (25 to 320 Pa) was quantified for ovine, porcine, bovine, and human blood, respectively. Within these ranges of shear stress and exposure time, shear-induced hemolysis was less than 2% for the four species. The results showed that the ovine blood was more susceptible to shear-induced injury than the bovine, porcine, and human blood. The response of the porcine and bovine blood to shear was similar to the human blood. The dependence of hemolysis on shear stress level and exposure time was found to fit well the power law functional form for the four species. The coefficients of the power law models for the ovine, porcine, bovine, and human blood were derived.

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“…In common cardiovascular devices, such as blood pumps and heart valves, the blood can be exposed to very high shear stress (>100 Pa) for a short period of time (<1 s) (2). To study blood damage under such flow conditions, Couette‐type blood‐shearing devices are used.…”

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confidence: 99%

Study of Flow-Induced Hemolysis Using Novel Couette-Type Blood-Shearing Devices

et al. 2011

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To assist the development and application of blood-contacting medical devices, two novel flow-through Couette-type blood-shearing devices have been developed to study the quantitative relationship between blood damage indexes and flow-dependent parameters. One device is an axial flow-through Couette-type device supported by a pair of pin bearings adapted from the adult Jarvik 2000 blood pump. The other is a centrifugal flow-through Couette-type device supported with magnetic bearings adapted from the CentriMag blood pump. In both devices, a rotor spindle was used to replace the original impeller blades so that a small gap was created between the housing and the rotating spindle surface. Computational fluid dynamics simulations have shown that a uniform, high shear stress region can be generated inside the small gap while the shear stresses elsewhere are relatively low. The possibility of secondary blood damage caused by mechanical seals was eliminated due to the use of a magnetic rotor system. Blood flow through the gap was driven by an externally pressurized reservoir. By adjusting the rotational speed and blood flow rate, shear-induced hemolysis was quantified at a matrix of exposure time (0.039 to 1.48 s) and shear stress (50 to 320 Pa). All of the experiments were conducted at room temperature using heparinized ovine blood with a hematocrit value of 30%. The measured hemolysis levels were much lower than those published in the literature, and the overestimation of those earlier studies may be attributable to device-related secondary blood-damaging effects. A new set of coefficients for the power law model was derived from the regression of the experimental data.

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Relative blood damage index of the jellyfish valve and the Bjork-Shiley tilting-disk valve

Cited by 11 publications

References 15 publications

Erythrocyte deformability responses to intermittent and continuous subhemolytic shear stress

Erythrocyte deformability responses to intermittent and continuous subhemolytic shear stress

Shear-Induced Hemolysis: Species Differences

Study of Flow-Induced Hemolysis Using Novel Couette-Type Blood-Shearing Devices

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