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Journal of Artificial Organs

, Volume 14, Issue 1, pp 70–73 | Cite as

What is the ideal off-test trial for continuous-flow ventricular-assist-device explantation? Intracircuit back-flow analysis in a mock circulation model

  • Masahiko AndoEmail author
  • Takashi Nishimura
  • Yoshiaki Takewa
  • Daisuke Ogawa
  • Kenji Yamazaki
  • Koichi Kashiwa
  • Shunei Kyo
  • Minoru Ono
  • Yoshiyuki Taenaka
  • Eisuke Tatsumi
Brief Communication

Abstract

Bridge to recovery has become a major goal after left-ventricular-assist-device (LVAD) implantation thanks to recent development in adjunctive therapies. Precise assessment of native heart function under minimum LVAD support is the key for successful LVAD explantation. However, weaning of centrifugal LVADs normally generates diastolic intracircuit backward flow. This retrograde flow may become excessive load for the native heart during off-pump test. The flow itself is an inevitable characteristic of centrifugal pumps. Therefore, evaluating this retrograde flow in vitro is of considerable significance, even if its amount is different from that in clinical settings. The purpose of this study was to assess diastolic backflow of continuous-flow centrifugal LVADs in a mock circulation model. A centrifugal LVAD (EVAHEART, Sun Medical Technology) was installed in a mock circulation model by the left ventricle uptake and the ascending aortic return. Pump flow was measured at the pump rotational speed of 1000, 1500, 2000, and 2500 rpm, and pulse rate of the virtual native heart was varied to 60, 90, and 120 beats/min. After data collection, pump flow was integrated, and forward and backward intracircuit flow were calculated. As a result, nonphysiological reverse flow of approximately 2.0 L/min exists at the rotational speed, providing 0 L/min mean pump flow. An ideal off-test trial condition should be realizing both ±0 L/min pump flow and no intracircuit backward flow at the same time. We are developing a novel EVAHEART drive mode that can change its rotational speed in synchronization with cardiac cycle with the aim of controlling this retrograde flow with the new drive mode and creating an ideal off-test condition.

Keywords

Left-ventricular-assist device Bridge to recovery Mock circulation model 

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Copyright information

© The Japanese Society for Artificial Organs 2011

Authors and Affiliations

  • Masahiko Ando
    • 1
    • 2
    Email author
  • Takashi Nishimura
    • 3
  • Yoshiaki Takewa
    • 1
  • Daisuke Ogawa
    • 6
  • Kenji Yamazaki
    • 5
  • Koichi Kashiwa
    • 4
  • Shunei Kyo
    • 3
  • Minoru Ono
    • 2
  • Yoshiyuki Taenaka
    • 1
  • Eisuke Tatsumi
    • 1
  1. 1.Department of Artificial OrganNational Cardiovascular Center Research InstituteSuitaJapan
  2. 2.Department of Cardiothoracic SurgeryThe University of TokyoTokyoJapan
  3. 3.Department of Therapeutic Strategy for Heart FailureThe University of TokyoTokyoJapan
  4. 4.Department of Medical EngineeringThe University of Tokyo HospitalTokyoJapan
  5. 5.Department of Cardiovascular SurgeryTokyo Women’s Medical UniversityTokyoJapan
  6. 6.Sun Medical Technology Research CorporationNaganoJapan

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