title: Numerical model of a valvuloplasty balloon: in vitro validation in a rapid-prototyped phantom.
abstract: BACKGROUND
  Patient-specific simulations can provide insight into the mechanics of cardiovascular procedures. Amongst cardiovascular devices, non-compliant balloons are used in several minimally invasive procedures, such as balloon aortic valvuloplasty. Although these balloons are often included in the computer simulations of these procedures, validation of the balloon behaviour is often lacking. We therefore aim to create and validate a computational model of a valvuloplasty balloon.
  
  
  METHODS
  A finite element (FE) model of a valvuloplasty balloon (Edwards 9350BC23) was designed, including balloon geometry and material properties from tensile testing. Young's Modulus and distensibility of different rapid prototyping (RP) rubber-like materials were evaluated to identify the most suitable compound to reproduce the mechanical properties of calcified arteries in which such balloons are likely to be employed clinically. A cylindrical, simplified implantation site was 3D printed using the selected material and the balloon was inflated inside it. The FE model of balloon inflation alone and its interaction with the cylinder were validated by comparison with experimental Pressure-Volume (P-V) and diameter-Volume (d-V) curves.
  
  
  RESULTS
  Root mean square errors (RMSE) of pressure and diameter were RMSE P = 161.98 mmHg (3.8 % of the maximum pressure) and RMSE d = 0.12 mm (<0.5 mm, within the acquisition system resolution) for the balloon alone, and RMSE P = 94.87 mmHg (1.9 % of the maximum pressure) and RMSE d = 0.49 mm for the balloon inflated inside the simplified implantation site, respectively.
  
  
  CONCLUSIONS
  This validated computational model could be used to virtually simulate more realistic valvuloplasty interventions.
authors.affiliation: Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science & Great Ormond Street Hospital for Children, Great Ormond Street, London, WC1N 3JH, UK. b.biffi@ucl.ac.uk.|Department of Medical Physics and Biomedical Engineering, University College London, London, UK. b.biffi@ucl.ac.uk.
authors.forename: Benedetta
authors.initials: B
authors.lastname: Biffi
authors.affiliation: Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science & Great Ormond Street Hospital for Children, Great Ormond Street, London, WC1N 3JH, UK.
authors.forename: Giorgia M
authors.initials: GM
authors.lastname: Bosi
authors.affiliation: Laboratory of Biological Structure Mechanics (LaBS), Chemistry, Materials and Chemical Engineering Department "Giulio Natta", Politecnico di Milano, Milan, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Lintas
authors.affiliation: Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science & Great Ormond Street Hospital for Children, Great Ormond Street, London, WC1N 3JH, UK.
authors.forename: Rod
authors.initials: R
authors.lastname: Jones
authors.affiliation: Department of Mechanical Engineering, UCL Faculty of Engineering Science, London, UK.
authors.forename: Spyros
authors.initials: S
authors.lastname: Tzamtzis
authors.affiliation: Department of Mechanical Engineering, UCL Faculty of Engineering Science, London, UK.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Burriesci
authors.affiliation: Laboratory of Biological Structure Mechanics (LaBS), Chemistry, Materials and Chemical Engineering Department "Giulio Natta", Politecnico di Milano, Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Migliavacca
authors.affiliation: Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science & Great Ormond Street Hospital for Children, Great Ormond Street, London, WC1N 3JH, UK.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Taylor
authors.affiliation: Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science & Great Ormond Street Hospital for Children, Great Ormond Street, London, WC1N 3JH, UK.
authors.forename: Silvia
authors.initials: S
authors.lastname: Schievano
authors.affiliation: Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science & Great Ormond Street Hospital for Children, Great Ormond Street, London, WC1N 3JH, UK.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Biglino
mesh_terms: D063126:Balloon Valvuloplasty / Q000295:instrumentation*; D055119:Elastic Modulus; D020342:Finite Element Analysis; D008422:Materials Testing; D055595:Mechanical Phenomena; D066230:Patient-Specific Modeling; D019047:Phantoms, Imaging; D011312:Pressure; D066330:Printing, Three-Dimensional; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D013718:Tensile Strength; D013997:Time Factors
keywords: 3D printing/rapid prototyping materials; Implantation site material properties; Percutaneous procedures; Validation of computational models; Valvuloplasty balloons