Antithrombogenic properties of a monopivot magnetic suspension centrifugal pump for circulatory assist.
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.
Yamane
Takashi
T
National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan. yamane.t@aist.go.jp
Maruyama
Osamu
O
Nishida
Masahiro
M
Kosaka
Ryo
R
Chida
Takahiro
T
Kawamura
Hiroshi
H
Kuwana
Katsuyuki
K
Ishihara
Kazuhiko
K
Sankai
Yoshiyuki
Y
Matsuzaki
Mio
M
Shigeta
Osamu
O
Enomoto
Yoshiharu
Y
Tsutsui
Tatsuo
T
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