title: Reduced leaflet stress in the stentless quadrileaflet mitral valve: a finite element model.
abstract: BACKGROUND
  Failure of bioprosthetics is usually caused by calcification of the leaflets as a consequence of high tensile stresses. The stentless valve resembles native mitral valve anatomy, has a flexible leaflet attachment and a suspension at the papillary muscles, and preserves annuloventricular continuity. In this study, the effects of the stentless valve design on leaflet stress were investigated with a finite element model.
  
  
  METHODS
  Finite element models of the stentless quadrileaflet mitral valve were created in the close and open configurations. The geometry of the stented trileaflet mitral valve was also analyzed for comparative purposes. Under the designated pressures, the regional stresses were evaluated, and the distributions of stresses were assessed.
  
  
  RESULTS
  Regardless of whether the valve is in the open or close configuration, the maximum first principal stress was significantly lower in the stentless valve than in the stented valve. For the stentless valves, limited stress concentration was discretely distributed in the papillary flaps under both close and open conditions. In contrast, in the stented valve, increased stress concentration was evident at the central belly under the open condition and at the commissural attachment under close condition. In either configuration, the maximum second principal stress was markedly lower in the stentless valve than in the stented valve.
  
  
  CONCLUSIONS
  The stentless valve was associated with a significant reduction in leaflet stress and a more homogeneous stress distribution compared to the stented valve. These findings are consistent with recent reports of the clinical effectiveness of the stentless quadrileaflet mitral valve.
authors.affiliation: Department of Cardiac Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China. wangjiangang7545@126.com
authors.forename: Jian-Gang
authors.initials: JG
authors.lastname: Wang
authors.forename: Xing-Cheng
authors.initials: XC
authors.lastname: Kuai
authors.forename: Bi-Qiao
authors.initials: BQ
authors.lastname: Ren
authors.forename: Guang-Fu
authors.initials: GF
authors.lastname: Gong
authors.forename: Xin-Min
authors.initials: XM
authors.lastname: Zhou
mesh_terms: D006350:Heart Valve Prosthesis; D006801:Humans; D008943:Mitral Valve / Q000033:anatomy & histology* / Q000502:physiology; D010210:Papillary Muscles / Q000033:anatomy & histology* / Q000502:physiology; D011312:Pressure; D011474:Prosthesis Design; D015607:Stents; D013314:Stress, Mechanical