Vol.5 No.1 2012

Research paper−17−Synthesiology - English edition Vol.5 No.1 pp.17-24 (Jun. 2012) a long-term VAD.The history of the artificial heart is that of overcoming thrombosis and infections. Dr. Kolff and Dr. Akutsu initiated animal experiments of an artificial heart in 1957 at the Cleveland Clinic Foundation Hospital. It was not before the development of antithrombogenic materials in 1981 that a clinical study started for a total replacement artificial heart. The subsequent clinical applications moved to implantable ventricular assist devices (VADs) from 1987. It enabled patients to go out of hospitals and reached the number of 4600 cases. The first generation of VADs was mainly large-size pulsatile pumps which weighed more than 1400 grams.Small-size rotary VADs were introduced in 1998 and an innovation occurred. They are called the second generation VADs, which use mechanical bearings. Clinical study for axial-flow pumps started in 1998 and the total number has reached 6500 up to now. Their merits are the small size for implantation, such as 200-500 g, and the reliability due to reduced number of components.The second innovation occurred when they introduced non-contact bearings in combination with the rotary mechanisms. They are called the third generation VADs and their clinical study started in 2004. They are using the magnetic bearing, which levitates the impeller with position sensors and electromagnets, or the hydrodynamic bearing, which levitates the impeller with grooves on the surfaces accompanied by high pressure spots, or the mechanical seal, which block the invasion of blood with thin liquid films. Most of them are centrifugal pumps, which are featured with hyper durability 1 Historical background of R&D of artificial heartsPopulation Statistics of the Ministry of Health, Labor and Welfare (MHLW) in 2010 indicates 350 thousand people died of cancer, 190 thousand died of heart disease, and 120 thousand died of brain/vessel disease. The second and the third causes sum up to 300 thousand people in total. Among them there are 195 heart transplantation nominees as the most serious patients. Even though the transplantation law was improved to include donors based on family agreement and the number of donors increased from 6 to 40, 150 donors are still lacking. The possible remedy for this situation is an artificial heart or regenerative medicine. However, in emergency cases, the artificial heart is the only choice for heart patients.History of the artificial heart technology is as follows: 1) Initiation as the total replacement artificial heart with large-scale pneumatic pumps,2) Change of the purpose from heart replacement to heart assistance (paracorporeal use),3) Out-of-hospital pumps with implantable ventricular assist devices (VAD),4) Reduction of size by using rotary blood pumps,5) Durability enhancement with non-contact bearings: the maximum period of use at present is 7.5 years.As surgical pumps6) Roller pumps or centrifugal pumps are limited to one-day use,7) The circulatory assist pumps with catheters are limited to one-week use,8) A new category of care, bridge-to-decision, is emerging, which is used for 1 to 12 months before the implantation of - Collaboration for a product between medical and engineering teams-AIST succeeded in developing a circulatory assist centrifugal pump, which can be used as a bridge-to-bridge device of a period within four weeks before a long-term use of ventricular assist device. The adopted mechanism of monopivot bearing was originally proposed by AIST. As design verification, flow visualization was performed to evaluate the geometry and the in vitro antithrombogenic testing, proposed originally by AIST, was applied to evaluate the antithrombogenicity. And then, the animal testing was conducted in collaboration between medical and engineering teams. AIST not only succeeded in developing a product with original seeds, but also established and distributed engineering evaluation methods and the R&D guidance for industries.Research and development of a monopivot centrifugal blood pump for clinical use Keywords : Artificial heart, centrifugal pump, monopivot bearing, flow visualization, in vitro antithrombogenic test[Translation from Synthesiology, Vol.5, No.1, p.16-24 (2012)]Takashi Yamane*, Osamu Maruyama, Masahiro Nishida, Ryo KOSAKAHuman Technology Research Institute, AIST 1-2-1 Namiki, tsukuba 305-8564, Japan *E-mail: (current affiliation: *Professor, Kobe University 1-1 Rokkoudai-machi Nada-ku kobe 657-8501, Japan *Email: )Original manuscript received September 5, 2011, Revisions received December 13, 2011, Accepted December 20, 2011


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