title: Percutaneous mitral valve dilatation: single balloon versus double balloon. A finite element study.
abstract: OBJECTIVE
  Percutaneous mitral valve (MV) dilatation is routinely performed for mitral stenosis using either a single balloon (SB) or double balloon (DB) technique. The study aim was to compare the two techniques using the finite element (FE) method.
  
  
  METHODS
  An established FE model of the MV was modified by fusing MV leaflet edges at commissure level to simulate a stenotic valve (orifice area = 180 mm2). FE models of a 30 mm SB (low-pressure, elastomeric balloon) and an 18 mm DB system (high-pressure, non-elastic balloon) were created.
  
  
  RESULTS
  Both, SB and DB simulations, resulted in the splitting of commissures and consequent relief of stenosis (final MV areas of 610 mm2 and 560 mm2, respectively). Stresses induced by the two balloon systems varied across the valve. At full inflation, SB showed a higher stress in the central part of the leaflets and at the commissures compared to DB simulation, which demonstrated a more uniform stress distribution. This was due to mismatch of the round shape of the SB within an oval mitral orifice. Due to its high compliance, commissural splitting was not easily accomplished with the SB. Conversely, the DB guaranteed commissural splitting, even when a high force was required to break the commissure welds.
  
  
  CONCLUSIONS
  The FE model demonstrated that MV dilatation can be accomplished by both SB and DB techniques. However, the DB method resulted in a higher probability of splitting the fused commissures, with less potential for damage to the MV leaflets by overstretching, even at higher pressures.
authors.affiliation: UCL Institute of Child Health & Great Ormond Street Hospital for Children, London, UK. s.schievano@ich.ucl.ac.uk
authors.forename: Silvia
authors.initials: S
authors.lastname: Schievano
authors.forename: Karyn
authors.initials: K
authors.lastname: Kunzelman
authors.forename: Mark A
authors.initials: MA
authors.lastname: Nicosia
authors.forename: Richard P
authors.initials: RP
authors.lastname: Cochran
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Einstein
authors.forename: Sachin
authors.initials: S
authors.lastname: Khambadkone
authors.forename: Philipp
authors.initials: P
authors.lastname: Bonhoeffer
mesh_terms: D001696:Biomechanical Phenomena; D002404:Catheterization / Q000295:instrumentation / Q000379:methods*; D020342:Finite Element Analysis; D006801:Humans; D066298:In Vitro Techniques; D008943:Mitral Valve / Q000502:physiology; D008946:Mitral Valve Stenosis / Q000628:therapy*; D008955:Models, Cardiovascular