title: Utilization of acoustic signatures to identify HeartMate XVE device end-of-life.
abstract: BACKGROUND
  As outcomes for destination therapy continue to improve, many patients are requiring left ventricular assist device (LVAD) exchange due to end-of-life of their LVAD. Current techniques to identify and diagnose device end-of-life issues usually require invasive testing or off-site filter dust analysis. In this study we assess a non-invasive technique using acoustic signals generated from the HeartMate XVE LVAD to potentially identify impending device end-of-life issues.
  
  
  METHODS
  Nine patients were prospectively followed after implantation of the HeartMate XVE LVAD as destination therapy between May 2004 and July 2006. Acoustic signals were collected using an aquatic hydrophone system interfaced with a data acquisition system and a standard laptop computer. Data were collected at pre-set intervals. All data/acoustic signals were prospectively interpreted by a blinded independent reviewer skilled at interpreting acoustic signals. Acoustic data suggesting possible device failure were then correlated with clinical findings and LVAD examination at the time of device removal.
  
  
  RESULTS
  All patients survived long enough to develop signs of impending device end-of-life. Four of 9 (44%) patients developed inflow valve incompetence, 4 (44%) were identified as having significant bearing wear, and 1 (12%) had both. All acoustically identified device issues were confirmed by standard clinical examinations and testing (echocardiography, angiography, laboratory tests and filter dust analysis). The acoustic findings were subsequently confirmed at time of device exchange. All patients ultimately had their device successfully exchanged and have continued to live with their new apparatus.
  
  
  CONCLUSIONS
  Acoustic signal monitoring can successfully identify HeartMate XVE device end-of-life. This new method provides a low-cost, reproducible, non-invasive technique that may be used to identify possible impending device failure.
authors.affiliation: Mechanical Assist Device Program, Advocate Christ Medical Center, Oak Lawn, Illinois 60453, USA. mscabg@aol.com
authors.forename: Mark S
authors.initials: MS
authors.lastname: Slaughter
authors.forename: Chad M
authors.initials: CM
authors.lastname: Feldman
authors.forename: Michael A
authors.initials: MA
authors.lastname: Sobieski
authors.forename: Marc A
authors.initials: MA
authors.lastname: Silver
authors.forename: Michele M
authors.initials: MM
authors.lastname: Martin
authors.forename: Sudha
authors.initials: S
authors.lastname: Kurien
authors.forename: Laura A
authors.initials: LA
authors.lastname: Coyle
authors.forename: Brian
authors.initials: B
authors.lastname: Pederson
mesh_terms: D000162:Acoustics; D004562:Electrocardiography; D004867:Equipment Design; D004868:Equipment Failure; D006333:Heart Failure / Q000628:therapy*; D006353:Heart-Assist Devices; D006801:Humans; D015203:Reproducibility of Results