title: Evaluation of a Spiral Groove Geometry for Improvement of Hemolysis Level in a Hydrodynamically Levitated Centrifugal Blood Pump.
abstract: The purpose of this study is to evaluate a spiral groove geometry for a thrust bearing to improve the hemolysis level in a hydrodynamically levitated centrifugal blood pump. We compared three geometric models: (i) the groove width is the same as the ridge width at any given polar coordinate (conventional model); (ii) the groove width contracts inward from 9.7 to 0.5 mm (contraction model); and (iii) the groove width expands inward from 0.5 to 4.2 mm (expansion model). To evaluate the hemolysis level, an impeller levitation performance test and in vitro hemolysis test were conducted using a mock circulation loop. In these tests, the driving conditions were set at a pressure head of 200 mm Hg and a flow rate of 4.0 L/min. As a result of the impeller levitation performance test, the bottom bearing gaps of the contraction and conventional models were 88 and 25 μm, respectively. The impeller of the expansion model touched the bottom housing. In the hemolysis test, the relative normalized index of hemolysis (NIH) ratios of the contraction model in comparison with BPX-80 and HPM-15 were 0.6 and 0.9, respectively. In contrast, the relative NIH ratios of the conventional model in comparison with BPX-80 and HPM-15 were 9.6 and 13.7, respectively. We confirmed that the contraction model achieved a large bearing gap and improved the hemolysis level in a hydrodynamically levitated centrifugal blood pump.
authors.affiliation: Graduate School of Science and Technology, Tokyo University of Science, Noda, Chiba, Japan.
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Murashige
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Kosaka
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sakota
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nishida
authors.affiliation: Tokyo University of Science, Noda, Chiba, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kawaguchi
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.|Kobe University, Kobe, Hyogo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamane
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Maruyama
mesh_terms: D000818:Animals; D002417:Cattle; D002498:Centrifugation; D006353:Heart-Assist Devices / Q000009:adverse effects*; D006439:Hemodynamics; D006461:Hemolysis; D008953:Models, Anatomic; D008955:Models, Cardiovascular; D011474:Prosthesis Design; D013314:Stress, Mechanical; D013997:Time Factors
keywords: Bearing gap; Centrifugal blood pump; Hemolysis; Hydrodynamic bearing; Spiral groove