title: Using contracting band to improve right ventricle ejection fraction for patients with repaired tetralogy of Fallot: a modeling study using patient-specific CMR-based 2-layer anisotropic models of human right and left ventricles.
abstract: OBJECTIVE
  Patients with repaired tetralogy of Fallot account for most cases of late-onset right ventricle failure. The current surgical approach, which includes pulmonary valve replacement/insertion, has yielded mixed results. A new surgical option of placing an elastic band in the right ventricle is proposed to improve right ventricular cardiac function as measured by the ejection fraction.
  
  
  METHODS
  A total of 20 computational right ventricular/left ventricular/patch/band combination models using cardiac magnetic resonance imaging from a patient with tetralogy of Fallot were constructed to investigate the effect of band material stiffness variations, band length, and active contraction. These models included 4 different band material properties, 3 band length, 3 active contracting band materials, and models with patch and scar replaced by contracting tissue.
  
  
  RESULTS
  Our results indicated that the band insertion, combined with active band contraction and tissue regeneration techniques that restore right ventricular myocardium, has the potential to improve right ventricular ejection fraction by 7.5% (41.63% ejection fraction from the best active band model to more than 34.10% ejection fraction from baseline passive band model) and 4.2% (41.63% from the best active band model compared with cardiac magnetic resonance imaging-measured ejection fraction of 37.45%).
  
  
  CONCLUSIONS
  The cardiac magnetic resonance imaging-based right ventricular/left ventricular/patch/band model provides a proof of concept for using elastic bands to improve right ventricular cardiac function. Band insertion, combined with myocardium regeneration techniques and right ventricular remodeling surgical procedures, has the potential to improve ventricular function in patients with repaired tetralogy of Fallot and other similar forms of right ventricular dysfunction after surgery. Additional investigations using in vitro experiments, animal models, and, finally, patient studies are warranted.
authors.affiliation: Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, Mass 01609, USA.
authors.forename: Chun
authors.initials: C
authors.lastname: Yang
authors.forename: Dalin
authors.initials: D
authors.lastname: Tang
authors.forename: Tal
authors.initials: T
authors.lastname: Geva
authors.forename: Rahul
authors.initials: R
authors.lastname: Rathod
authors.forename: Haruo
authors.initials: H
authors.lastname: Yamauchi
authors.forename: Vasu
authors.initials: V
authors.lastname: Gooty
authors.forename: Alexander
authors.initials: A
authors.lastname: Tang
authors.forename: Glenn
authors.initials: G
authors.lastname: Gaudette
authors.forename: Kristen L
authors.initials: KL
authors.lastname: Billiar
authors.forename: Mehmet H
authors.initials: MH
authors.lastname: Kural
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: del Nido
mesh_terms: D016880:Anisotropy; D001696:Biomechanical Phenomena; D006348:Cardiac Surgical Procedures / Q000295:instrumentation; D003198:Computer Simulation; D017076:Computer-Aided Design; D003250:Constriction; D004548:Elasticity; D004867:Equipment Design; D006801:Humans; D008279:Magnetic Resonance Imaging; D008955:Models, Cardiovascular; D020127:Recovery of Function; D013314:Stress, Mechanical; D013318:Stroke Volume; D013771:Tetralogy of Fallot / Q000150:complications / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome; D018497:Ventricular Dysfunction, Right / Q000209:etiology / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D016278:Ventricular Function, Right