title: Development of the Nimbus/University of Pittsburgh innovative ventricular assist system.
abstract: BACKGROUND
  Nimbus Inc, and the University of Pittsburgh's McGowan Center for Artificial Organ Development have been collaborators on rotary blood pump technology initiatives since 1992. Currently, a major focus is an innovative ventricular assist system (IVAS) that features an implantable, electrically powered axial flow blood pump. In addition to the blood pump, a major development item is the electronic controller and the control algorithm for modulating pump speed in response to varying physical demand.
  
  
  METHODS
  Methods used in developing the IVAS include computational fluid dynamic modeling of the pump's interior flow field, flow visualization of the flow field using laser-based imaging, computer simulation of blood pump-physiological interactions, vibroaccoustic monitoring, and an extensive in vivo test program.
  
  
  RESULTS
  Results to date, which are presented below, include successful in vivo tests of blood pumps with blood-immersed bearings, and feasibility demonstration of vibroacoustic monitoring in this application.
  
  
  CONCLUSIONS
  This unique blend of industrial experience and technologies with the University-based Research and Development Center has greatly enhanced the progress made on this IVAS project.
authors.affiliation: Nimbus Inc, Rancho Cordova, California 95670, USA. kcbutler@pacbell.net
authors.forename: K C
authors.initials: KC
authors.lastname: Butler
authors.forename: J J
authors.initials: JJ
authors.lastname: Dow
authors.forename: P
authors.initials: P
authors.lastname: Litwak
authors.forename: R L
authors.initials: RL
authors.lastname: Kormos
authors.forename: H S
authors.initials: HS
authors.lastname: Borovetz
mesh_terms: D000818:Animals; D002417:Cattle; D004867:Equipment Design; D006333:Heart Failure / Q000209:etiology / Q000401:mortality / Q000601:surgery*; D006353:Heart-Assist Devices; D006785:Hospitals, University; D006801:Humans; D008955:Models, Cardiovascular; D010414:Pennsylvania; D011673:Pulsatile Flow