Study on regurgitation of a bearing-less mini axial aortic valvo-pump with closed impeller

Kun-Xi Qian
DOI: 10.4236/health.2009.13028                

Abstract

The back-flow of an aortic valvo-pump will re-duce the pumping flow rate but can wash out the gap between the rotor and the stator, and thus can improve the antithrombogenicity of the de-vice. To investigate the regurgitation of a 23mm OD aortic valvo-pump, its closed impeller was replaced by a cylinder and hereby the valvo- pump had lost its pumping function. The pres-sure head crossing the aortic valvo-pump was maintained by a locally made pulsatile centrifugal pump, beating rhythmically from 30 to 120mmHg. The back flow from outlet to inlet of valvo-pump via the above-mentioned gap was measured. Results demonstrated that this gap and the pressure head had remarkable effect on back- flow; a larger gap and/or a larger pressure head would lead to a larger back-flow. By 0,20mm gap and 100mmHg pressure head, the valvo-pump had ca. 0,8 l/min back-flow. Instantaneous meas-urement indicated that the back-flow had a pul-satile form with high rate during diastole while low rate during systole of the natural heart imi-tated by pulsatile centrifugal pump. The pump rotated at 12500rpm, 15000rpm and 17500rpm respectively, but it was found the rotating speed had no affection on back-flow. This investigation provides a basis for pump design seeking for both increase of the flow rate and improvement of the compatibility; the former is particularly important for a mini axial pump and the latter is extremely difficult for closed impeller.

Keywords

Aortic Valvo-Pump; Regurgitation Measurement; Different Air-Gap and Pressure Head; Anti-Thrombogenicity

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	K. X. Qian, D. F. Wang, S. Topaz, W. M. Ru, P. Zeng, H. Y. Yuan, J. B. Zwischenberg, (2005) Use of implantable aortic valvo-pump placed in valve annulus for long term left ventricular assist. ASAIO J., 52(6).
[2]	K. X. Qian, W. M. Ru, P. Zeng, H. Y. Yuan, (2005) Pre-sent status and prospects of research and development of artificial heart pump and aortic valvo-pump in Jiangsu University. Chn J Med Instrumentation., 23(4).
[3]	K. X. Qian, W. M. Ru, P. Zeng, H. Y. Yuan, (2005) World-first implantable aortic valvo-pump with sufficient hemo-dynamic property. J Med Eng Techn., 29(2), 302-304.
[4]	K. X. Qian, W. M. Ru, P. Zeng, H. Y. Yuan, (2007) World- smallest LVAD with 27g weight and 21mm OD can pro-duce 5l/min flow with 50mmHg pressure increase. J Med Eng Techn, 31(3), 181-184.
[5]	K. X. Qian, (2002) Axial reciprocation of rotating impel-ler: A novel approach to preventing thrombosis in cen-trifugal pump. ASAIO Journal, 48(48), 562-564.
[6]	K. X. Qian, (1994) Pulsatile blood flow from impeller pump: A dream has come true. Journal of Biomaterials Applications, 9(2), 158-177.
[7]	K. X. Qian, (1995) Pulsatile centrifugal impeller heart a successful application of engineering to medicine, Bio-medical Engineering Applications. Basis Communica-tions, 7(3), 263-275.
[8]	K. X. Qian, (2009) Connecting conduit-free and bypass circuit-less mini LVADs eliminate the most likely sites of thrombosis. Health, 1(1), 31-34.