title: Partial mechanical circulatory support in an ovine model of post-infarction remodeling.
abstract: BACKGROUND
  Full unloading of the left ventricle (LV) in chronic heart failure (CHF) induces reversal of LV dilation and geometric distortion. In this study we describe the partial unloading effects in ischemic CHF.
  
  
  METHODS
  Six weeks after myocardial infarction, sheep were randomized to partial support ("pump," n = 5), as provided by the CircuLite Synergy micro-pump, or to no therapy ("sham," n = 6) for an additional 6 weeks. At baseline, and at 6 and 12 weeks after infarction, pressure-volume (PV) recordings were made. Systolic and diastolic functions were characterized by the end-systolic volume (ESV) where LV end-systolic pressure reached 90 mm Hg (V90), and the end-diastolic volume (EDV) where LV end-diastolic pressure reached 15 mm Hg (V15), respectively. Magnetic resonance imaging (MRI) was performed 6 and 12 weeks after infarction. During autopsy at 12 weeks, isolated LVs were weighed. Histologically, the degree of fibrosis in the non-infarcted area was assessed using systematic randomized sampling, and myocyte hypertrophy was measured by the mean linear intercept method.
  
  
  RESULTS
  At 6 weeks, PV measurements showed a V90 and V15 increase (p = NS between groups). Six weeks later, V90 and V15 increased in the sham group. In the pump group, V90 decreased but V15 did not change significantly. At 6 weeks, MRI indicated no significant difference between groups. Six weeks later, in the sham group, EDV and ESV increased significantly. In the pump group, EDV decreased significantly and ESV trended to decrease. Sphericity index increased in the sham group and decreased in the pump group, although not significantly. Explanted LV masses were significantly higher in the sham group than in the pump group. The pump group had a decrease in fibrosis and less myocyte hypertrophy.
  
  
  CONCLUSIONS
  Partial support 6 weeks after major myocardial infarction halts and reverses ventricular dilation and hypertrophy.
authors.affiliation: Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium. jefgeens1979@gmail.com
authors.forename: Jef H
authors.initials: JH
authors.lastname: Geens
authors.forename: Steven
authors.initials: S
authors.lastname: Jacobs
authors.forename: Piet
authors.initials: P
authors.lastname: Claus
authors.forename: Sander
authors.initials: S
authors.lastname: Trenson
authors.forename: Veerle
authors.initials: V
authors.lastname: Leunens
authors.forename: Ingrid
authors.initials: I
authors.lastname: Vantichelen
authors.forename: Filip R
authors.initials: FR
authors.lastname: Rega
authors.forename: Erik K
authors.initials: EK
authors.lastname: Verbeken
authors.forename: Daniel
authors.initials: D
authors.lastname: Burkhoff
authors.forename: Bart
authors.initials: B
authors.lastname: Meyns
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006333:Heart Failure / Q000601:surgery; D006353:Heart-Assist Devices; D006439:Hemodynamics; D012756:Sheep; D020257:Ventricular Remodeling
keywords: chronic heart failure; myocardial infarction; partial support; reverse remodeling; sheep model; ventricular assist devices (VADs)