title: Biventricular finite element modeling of the Acorn CorCap Cardiac Support Device on a failing heart.
abstract: BACKGROUND
  The Acorn CorCap Cardiac Support Device (CSD; Acorn Cardiovascular Inc, St. Paul, MN) is a woven polyester jacket that is placed around the heart and designed to reverse the progressive remodeling associated with dilated cardiomyopathy. However, the effects of the Acorn CSD on myofiber stress and ventricular function remain unknown. We tested the hypothesis that the Acorn CSD reduces end-diastolic (ED) myofiber stress.
  
  
  METHODS
  A previously described weakly coupled biventricular finite element (FE) model and circulatory model based on magnetic resonance images of a dog with dilated cardiomyopathy was used. Virtual applications of the CSD alone (Acorn), CSD with rotated fabric fiber orientation (rotated), CSD with 5% prestretch (tight), and CSD wrapped only around the left ventricle (LV; LV-only) were performed, and the effect on myofiber stress at ED and pump function was calculated.
  
  
  RESULTS
  The Acorn CSD has a large effect on ED myofiber stress in the LV free wall, with reductions of 55%, 79%, 92%, and 40% in the Acorn, rotated, tight, and LV-only cases, respectively. However, there is a tradeoff in which the Acorn CSD reduces stroke volume at LV end-diastolic pressure of 8 mm Hg by 23%, 25%, 30%, and 7%, respectively, in the Acorn, rotated, tight, and LV-only cases.
  
  
  CONCLUSIONS
  The Acorn CSD significantly reduces ED myofiber stress. However, CSD wrapped only around the LV was the only case with minimal negative effect on pump function. Findings suggest that LV-only CSD and Acorn fabric orientation should be optimized to allow maximal myofiber stress reduction with minimal reduction in pump function.
authors: Department of Mechanical Engineering, University of Kentucky, Lexington, Kentucky, USA.
authors: Jonathan F
authors: JF
authors: Wenk
authors: Liang
authors: L
authors: Ge
authors: Zhihong
authors: Z
authors: Zhang
authors: Dimitri
authors: D
authors: Mojsejenko
authors: D Dean
authors: DD
authors: Potter
authors: Elaine E
authors: EE
authors: Tseng
authors: Julius M
authors: JM
authors: Guccione
authors: Mark B
authors: MB
authors: Ratcliffe
mesh_terms: D000818:Animals; D002311:Cardiomyopathy, Dilated / Q000601:surgery*; D004195:Disease Models, Animal; D004285:Dogs; D004867:Equipment Design; D004869:Equipment Safety; D020342:Finite Element Analysis; D006334:Heart Function Tests; D006353:Heart-Assist Devices; D008422:Materials Testing; D011897:Random Allocation; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D020257:Ventricular Remodeling / Q000502:physiology*
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