title: Effects of pulsatile- and continuous-flow left ventricular assist devices on left ventricular unloading.
abstract: BACKGROUND
  In patients with end-stage heart failure, the use of left ventricular assist devices (LVADs) has improved clinical outcomes. Although newer continuous-flow devices have significant advantages, the effect of continuous flow on left ventricular unloading and hemodynamics is less well established. The aim of this investigation was to compare the effects of pulsatile- vs continuous-flow LVADs on left ventricular reverse remodeling and hemodynamic indices.
  
  
  METHODS
  Thirty-five patients undergoing implantation with a pulsatile volume displacement pump operating at fixed speed (n = 15; HeartMate XVE; Thoratec Corp., Pleasanton, CA) or a continuous-flow rotary pump with an axial design operating at a fixed rotor speed (n = 20; HeartMate II; Thoratec) were evaluated. Right heart catheterization and echocardiography were performed pre-operatively, and at 1- and 6-month follow-up intervals.
  
  
  RESULTS
  Thirty-five of 40 eligible patients with end-stage heart failure were included in this study. When used at fixed speed, use of both devices led to a substantial reduction in left ventricular volumes and dimensions at 1 month (p < 0.01). A marked and sustained reduction in filling pressures was also noted with both devices at 1 and 6 months (p < 0.01). The volume and pressure unloading effects of the HeartMate XVE were not superior to those with the HeartMate II (all p-values not statistically significant).
  
  
  CONCLUSIONS
  Substantial left ventricular unloading and hemodynamic improvement is achieved with the HeartMate XVE and the HeartMate II. We conclude that continuous-flow LVADs are as effective as pulsatile-flow LVADs with regard to degree of left ventricular unloading and cardiac hemodynamics.
authors.affiliation: Department of Cardiology, University of Minnesota, Minneapolis, Minnesota 55455, USA. garci205@umn.edu
authors.forename: Santiago
authors.initials: S
authors.lastname: Garcia
authors.forename: Forum
authors.initials: F
authors.lastname: Kandar
authors.forename: Andrew
authors.initials: A
authors.lastname: Boyle
authors.forename: Monica
authors.initials: M
authors.lastname: Colvin-Adams
authors.forename: Kenneth
authors.initials: K
authors.lastname: Lliao
authors.forename: Lyle
authors.initials: L
authors.lastname: Joyce
authors.forename: Ranjit
authors.initials: R
authors.lastname: John
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D002543:Cerebral Hemorrhage / Q000209:etiology / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000503:physiopathology / Q000628:therapy*; D006353:Heart-Assist Devices / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D011673:Pulsatile Flow / Q000502:physiology*; D020521:Stroke / Q000209:etiology / Q000503:physiopathology; D016896:Treatment Outcome; D020257:Ventricular Remodeling / Q000502:physiology*