title: Extended in vivo evaluation of a miniaturized axial flow pump with a novel inflow cannula for a minimal invasive implantation procedure.
abstract: BACKGROUND
  Minimally invasive techniques are desirable to minimize surgical trauma during left ventricular assist device (LVAD) implantation. This is particularly challenging for full-flow support. In this study, a minimally invasive implantation technique was developed for a microaxial rotary pump. The system was evaluated in a chronic sheep model.
  
  
  METHODS
  A HeartWare MVAD (HeartWare, Miami Lakes, FL) pump (length, 50 mm; diameter, 21 mm; maximum flow, 7-8 liters/min) was combined with a novel inflow cannula, including a new flow-optimized tip. The device was implanted into sheep (range, 60-80 kg, mean, 71.6 ± 6.8 kg) through a right-sided minithoracotomy. The inflow cannula was inserted through the superior pulmonary vein, passing through the left atrium into the left ventricle. Scheduled implant period was 30 days for 8 sheep and 100 days for 3 sheep. Mean support flow was set to half of the nominal cardiac output.
  
  
  RESULTS
  Six of 8 sheep finished the scheduled 30-day investigation period (one failed due to early non-pump-related post-operative bleeding and one due to prototype controller failure). The 3 sheep scheduled for 100 days reached the study end point. Peak pump flows of up to 6.9 liters/min were achieved. At necropsy, no signs of mitral valve lesions or thrombus formation around the cannula, the tip, or the insertion site were observed, except for valve leaflet erosion in 1 animal, where the cannula had been entangled in the sub-valvular chords due to lack of ultrasound monitoring.
  
  
  CONCLUSIONS
  The minimally invasive implantation technique using the HeartWare MVAD pump, together with a new cannula, provided excellent results in a chronic animal model.
authors.affiliation: Center for Medical Physics and Biomedical Engineering; Department of Cardiothoracic Surgery, Medical University of Vienna, Vienna, Austria; Ludwig-Boltzmann-Cluster for Cardiovascular Research, Vienna, Austria. Electronic address: heinrich.schima@meduniwien.ac.at.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Schima
authors.affiliation: Department of Cardiothoracic Surgery, Medical University of Vienna, Vienna, Austria; Heartware Inc, Miami Lakes, Florida.
authors.forename: Philipp
authors.initials: P
authors.lastname: Zrunek
authors.affiliation: Center for Medical Physics and Biomedical Engineering; Ludwig-Boltzmann-Cluster for Cardiovascular Research, Vienna, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Stoiber
authors.affiliation: Heartware Inc, Miami Lakes, Florida.
authors.forename: Jeff
authors.initials: J
authors.lastname: Larose
authors.affiliation: Heartware Inc, Miami Lakes, Florida.
authors.forename: Charles
authors.initials: C
authors.lastname: Shambaugh
authors.affiliation: Heartware Inc, Miami Lakes, Florida.
authors.forename: Dan
authors.initials: D
authors.lastname: Tamez
authors.affiliation: Department of Cardiothoracic Surgery, Medical University of Vienna, Vienna, Austria.
authors.forename: Zeno
authors.initials: Z
authors.lastname: Deckert
authors.affiliation: Division of Biomedical Research, Medical University of Vienna, Vienna, Austria.
authors.forename: Roberto
authors.initials: R
authors.lastname: Plasenzotti
authors.affiliation: Division of Biomedical Research, Medical University of Vienna, Vienna, Austria; Ludwig-Boltzmann-Cluster for Cardiovascular Research, Vienna, Austria.
authors.forename: Helga
authors.initials: H
authors.lastname: Bergmeister
authors.affiliation: Department of Cardiothoracic Surgery, Medical University of Vienna, Vienna, Austria; Ludwig-Boltzmann-Cluster for Cardiovascular Research, Vienna, Austria.
authors.forename: Georg
authors.initials: G
authors.lastname: Wieselthaler
mesh_terms: D000818:Animals; D057785:Catheters; D019544:Equipment Failure Analysis; D005260:Female; D006325:Heart Atria / Q000473:pathology / Q000601:surgery; D006353:Heart-Assist Devices; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008422:Materials Testing; D008904:Miniaturization; D019060:Minimally Invasive Surgical Procedures; D008943:Mitral Valve / Q000473:pathology / Q000601:surgery; D011474:Prosthesis Design; D012756:Sheep; D013908:Thoracotomy
keywords: LVAD; atrial cannulation; miniaturized; minimal invasive