title: Antithrombogenic properties of a monopivot magnetic suspension centrifugal pump for circulatory assist.
abstract: The National Institute of Advanced Industrial Science and Technology (AIST) monopivot magnetic suspension centrifugal pump (MC105) was developed for open-heart surgery and several weeks of circulatory assist. The monopivot centrifugal pump has a closed impeller of 50 mm in diameter, supported by a single pivot bearing, and is driven through a magnetic coupling to widen the fluid gap. Design parameters such as pivot length and tongue radius were determined through flow visualization experiments, and the effectiveness was verified in preliminary animal experiments. The maximum overall pump efficiency reached 18%, and the normalized index of hemolysis tested with bovine blood was as low as 0.0013 g/100 L. Animal experiments with MC105 were conducted in sheep for 3, 15, 29, and 35 days in a configuration of left ventricle bypass. No thrombus was formed around the pivot bearing except when the pump speed was reduced by 20% of normal operational speed, which reduced the pump flow by 40% to avoid inlet suction. Subsequently, the antithrombogenic design was verified in animal experiments for 5 weeks at a minimum rotational speed of greater than 1500 rpm and a minimum pump flow greater than 1.0 L/min; no thrombus formation was observed under these conditions.
authors.affiliation: National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan. yamane.t@aist.go.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamane
authors.forename: Osamu
authors.initials: O
authors.lastname: Maruyama
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nishida
authors.forename: Ryo
authors.initials: R
authors.lastname: Kosaka
authors.forename: Takahiro
authors.initials: T
authors.lastname: Chida
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawamura
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Kuwana
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ishihara
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Sankai
authors.forename: Mio
authors.initials: M
authors.lastname: Matsuzaki
authors.forename: Osamu
authors.initials: O
authors.lastname: Shigeta
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Enomoto
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Tsutsui
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D006353:Heart-Assist Devices; D006461:Hemolysis; D008280:Magnetics / Q000295:instrumentation*; D012756:Sheep; D013927:Thrombosis / Q000097:blood*; D014914:Whole Blood Coagulation Time