title: The helical flow pump with a hydrodynamic levitation impeller.
abstract: The helical flow pump (HFP) is a novel rotary blood pump invented for developing a total artificial heart (TAH). The HFP with a hydrodynamic levitation impeller, which consists of a multi-vane impeller involving rotor magnets, stator coils at the core position, and double helical-volute pump housing, was developed. Between the stator and impeller, a hydrodynamic bearing is formed. Since the helical volutes are formed at both sides of the impeller, blood flows with a helical flow pattern inside the pump. The developed HFP showed maximum output of 19 l/min against 100 mmHg of pressure head and 11 % maximum efficiency. The profile of the H-Q (pressure head vs. flow) curve was similar to that of the undulation pump. Hydrodynamic levitation of the impeller was possible with higher than 1,000 rpm rotation speed. The normalized index of the hemolysis ratio of the HFP to centrifugal pump (BPX-80) was from 2.61 to 8.07 depending on the design of the bearing. The HFP was implanted in two goats with a left ventricular bypass method. After surgery, hemolysis occurred in both goats. The hemolysis ceased on postoperative days 14 and 9, respectively. In the first experiment, no thrombus was found in the pump after 203 days of pumping. In the second experiment, a white thrombus was found in the pump after 23 days of pumping. While further research and development are necessary, we are expecting to develop an excellent TAH with the HFP.
authors.affiliation: Department of Biomedical Engineering, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan. abe@bme.gr.jp
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Abe
authors.forename: Kohei
authors.initials: K
authors.lastname: Ishii
authors.forename: Takashi
authors.initials: T
authors.lastname: Isoyama
authors.forename: Itsuro
authors.initials: I
authors.lastname: Saito
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Inoue
authors.forename: Toshiya
authors.initials: T
authors.lastname: Ono
authors.forename: Hidemoto
authors.initials: H
authors.lastname: Nakagawa
authors.forename: Emiko
authors.initials: E
authors.lastname: Nakano
authors.forename: Kyoko
authors.initials: K
authors.lastname: Fukazawa
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ishihara
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Fukunaga
authors.forename: Minoru
authors.initials: M
authors.lastname: Ono
authors.forename: Kou
authors.initials: K
authors.lastname: Imachi
mesh_terms: D000818:Animals; D001698:Biomedical Engineering; D004867:Equipment Design; D006041:Goats; D006354:Heart, Artificial; D006353:Heart-Assist Devices / Q000009:adverse effects; D006461:Hemolysis; D057446:Hydrodynamics; D012212:Rheology