Vol.5 No.1 2012

Research paper : Research and development of a monopivot centrifugal blood pump for clinical use (T. Yamane et al.)−21−Synthesiology - English edition Vol.5 No.1 (2012) Technology Research/Waseda Universitya centrifugal blood pump of Nikkiso/Baylor Medical Universitya centrifugal blood pump of Kyocera/Baylor Medical University4.3 Summery of outcomesAs mentioned above, AIST conducted R&D mainly on the hemocompatibility and durability of the design. The monopivot centrifugal pump features: 1) Small wear, silent sound, durable over four weeks.2) Thrombus free, low hemolysis, hemocompatible over four weeks.3) The product can be offered with a low price as a surgical pump in addition to having the above performance.The following AIST original technologies were useful in the development:1) “Monopivot bearing” is a mechanism AIST proposed internationally.[2] Wear, hemolysis, and thrombus formation occur at the monopivot and it was theoretically and experimentally verified that the contact area has a close relation to them.[3] The hemocompatibility and the durability were verified to be effective over 4 weeks.2) We proposed “flow visualization technique” which can predict quantitatively the hemocompatibility.[5][6] After our presentations flow visualization sessions were increased in international conferences and ISO 14708-5 adopted flow visualization as an ANNEX. As mentioned later the obtained data of the flow visualization was used as the application for the PMDA or for US Food and Drug Administration (FDA) and they were approved.3) “In vitro thrombogenic test” was a method we proposed for evaluation of hemocompatibility before animal experiments.[7] Though this method is still under development, there are several companies doing collaborative researches with us.On the other hand, the original technologies of the company were as follows:1) Cost reduction by adopting an assembling method without seals or adhesive materials.2) Cost reduction by removal of permanent magnets or ceramic components.3) Inhouse manufacturing of a motor driving unit with a radial-flux magnetic coupling.As a result, the equivalent function to a pneumatic driven VAD of 3,160,000 yen was realized with a centrifugal pump of around 60,000 yen. Furthermore, AIST inhouse program for patent application to a product was useful especially for establishing the business plan. 5 Outcome as a productSenko Medical Instrument Mfg. Co. Ltd. started the collaboration research with us in 2002, submitted the pharmaceutical application at the end of 2008 regarding “MERA centrifugal pump (HCF-MP23)” and obtained the approval in January 2011. The pump was launched into the market in April 2011, and the total number of clinical applications was more than 100 at the end of November Fig. 5 Prevention of thrombus formation through in vitro thrombogenic testThe closed circuit including a test pump was filled with purchased bovine blood, and sodium citrate and calcium chloride were added to maintain the active clotting time (ACT) to be around 200 s and the temperature at 37 °C for two hoursFig. 4 Prevention of thrombus formation through flow visualization and computational fluid dynamic analysisElimination of thrombus formation by predicting thrombus at the corner of the pivot supportBefore improvementAfter improvemant(a)Flow visualization(b)Computational Fluid DynamicsRelative speedDirection of rotation7065605550454035302520151050PaBlack ~0.5[m/s]Blue 0.5~1.0[m/s]Green 1.0~1.5[m/s]Red 1.5~[m/s]Before improvementAfter improvementTRY 6.0TRY 9.0


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