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  • SAGE Publications  (2)
  • Gui, Xing-Min  (2)
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  • SAGE Publications  (2)
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  • 1
    Online Resource
    Online Resource
    SAGE Publications ; 2017
    In:  The International Journal of Artificial Organs Vol. 40, No. 9 ( 2017-09), p. 489-497
    In: The International Journal of Artificial Organs, SAGE Publications, Vol. 40, No. 9 ( 2017-09), p. 489-497
    Abstract: A fully implantable axial left ventricular assist device LAP31 was developed for Chinese or other heart failure patients who need partial support. Based on the 5-Lpm total cardiac blood output of Chinese without heart failure disease, the design point of LAP31 was set to a flow rate of 3 Lpm with 100-mmHg pressure head. To achieve the required pressure head and good hemolytic performance, a structure that includes a spindly rotor hub and a diffuser with splitter and cantilevered main blades was developed. Computational fluid dynamics (CFD) was used to analyze the hydraulic and hemodynamic performance of LAP31. Then in vitro hydraulics experiments were conducted. The numerical simulation results show that LAP31 could generate a 1 to 8 Lpm flow rate with a 60.9 to 182.7 mmHg pressure head when the pump was rotating between 9,000 and 12,000 rpm. The average scalar shear stress of the blood pump was 21.7 Pa, and the average exposure time was 71.0 milliseconds. The mean hemolysis index of LAP31 obtained using Heuser's hemolysis model and Giersiepen's model was 0.220% and 3.89 × 10 5% respectively. After adding the splitter blades, the flow separation at the suction surface of the diffuser was reduced. The cantilever structure reduced the tangential velocity from 6.1 to 4.7–1.4 m/s within the blade gap by changing the blade gap from shroud to hub. Subsequently, the blood damage caused by shear stress was reduced. In conclusion, the hydraulic and hemolytic characteristics of the LAP31 are acceptable for partial support.
    Type of Medium: Online Resource
    ISSN: 0391-3988 , 1724-6040
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2017
    detail.hit.zdb_id: 1474999-3
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  • 2
    In: The International Journal of Artificial Organs, SAGE Publications, Vol. 42, No. 4 ( 2019-04), p. 182-189
    Abstract: Adverse events caused by flow-induced thrombus formation around the bearing/shaft of an axial blood pump remain a serious problem for axial blood pumps. Moreover, excessive anticoagulation with thrombosis around the bearing potentially increases the risk of postoperative gastrointestinal bleeding. The purpose of this study is to analyze the influence of the bearing structure on the thrombosis potential of an axial blood pump. The bearing/shaft structure was embedded into an axial blood pump numerical model. The numerical simulation and analysis are focused on the low wall shear stresses, recirculation, and residence time close to the bearing region to evaluate the potential for thrombosis around the bearing. Then, the flow field near the blood pump bearing was tested via in vitro particle image velocimetry experiments to verify the numerical results. The simulation results showed that after embedding the bearing/shaft structure a recirculation zone appeared in the outlet guide vane bearing/shaft region, the residence time increased 11-fold in comparison to the pump without the bearing/shaft structure, the scalar shear stress in the shaft surface was less than 7.8 Pa, and the stress accumulation was less than 0.10 Pa s. The numerical results showed that platelets that flow through the bearing region are exposed to significantly lower wall shear stress and a longer residence time, leading to activated platelet adhesion. The reduced stress accumulation and increased time in the bearing region lead to increased platelet activation.
    Type of Medium: Online Resource
    ISSN: 0391-3988 , 1724-6040
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2019
    detail.hit.zdb_id: 1474999-3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
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