title: Mechanical stress is associated with right ventricular response to pulmonary valve replacement in patients with repaired tetralogy of Fallot.
abstract: OBJECTIVE
  Patients with repaired tetralogy of Fallot account for a substantial proportion of cases with late-onset right ventricular failure. The current surgical approach, which includes pulmonary valve replacement/insertion, has yielded mixed results. Therefore, it may be clinically useful to identify parameters that can be used to predict right ventricular function response to pulmonary valve replacement.
  
  
  METHODS
  Cardiac magnetic resonance data before and 6 months after pulmonary valve replacement were obtained from 16 patients with repaired tetralogy of Fallot (8 male, 8 female; median age, 42.75 years). Right ventricular ejection fraction change from pre- to postpulmonary valve replacement was used as the outcome. The patients were divided into group 1 (n = 8, better outcome) and group 2 (n = 8, worst outcome). Cardiac magnetic resonance-based patient-specific computational right ventricular/left ventricular models were constructed, and right ventricular mechanical stress and strain, wall thickness, curvature, and volumes were obtained for analysis.
  
  
  RESULTS
  Our results indicated that right ventricular wall stress was the best single predictor for postpulmonary valve replacement outcome with an area under the receiver operating characteristic curve of 0.819. Mean values of stress, strain, wall thickness, and longitudinal curvature differed significantly between the 2 groups with right ventricular wall stress showing the largest difference. Mean right ventricular stress in group 2 was 103% higher than in group 1.
  
  
  CONCLUSIONS
  Computational modeling and right ventricular stress may be used as tools to identify right ventricular function response to pulmonary valve replacement. Large-scale clinical studies are needed to validate these preliminary findings.
authors.affiliation: School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, China; Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, Mass. Electronic address: dtang@wpi.edu.
authors.forename: Dalin
authors.initials: D
authors.lastname: Tang
authors.affiliation: Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, Mass; China Information Technology Designing & Consulting Institute Co, Ltd, Beijing, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Yang
authors.affiliation: Department of Cardiac Surgery, Boston Children's Hospital, Department of Surgery, Harvard Medical School, Boston, Mass.
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Del Nido
authors.affiliation: Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, Mass.
authors.forename: Heng
authors.initials: H
authors.lastname: Zuo
authors.affiliation: Department of Cardiology, Boston Children's Hospital, Department of Pediatrics, Harvard Medical School, Boston, Mass.
authors.forename: Rahul H
authors.initials: RH
authors.lastname: Rathod
authors.affiliation: Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, Mass; School of Mathematical Sciences, Xiamen University, Xiamen, Fujian, China.
authors.forename: Xueying
authors.initials: X
authors.lastname: Huang
authors.affiliation: Department of Cardiology, Boston Children's Hospital, Department of Pediatrics, Harvard Medical School, Boston, Mass.
authors.forename: Vasu
authors.initials: V
authors.lastname: Gooty
authors.affiliation: Department of Cardiac Surgery, Boston Children's Hospital, Department of Surgery, Harvard Medical School, Boston, Mass.
authors.forename: Alexander
authors.initials: A
authors.lastname: Tang
authors.affiliation: Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, Mass; Department of Surgery, University of Massachusetts Medical School, Worcester, Mass.
authors.forename: Kristen L
authors.initials: KL
authors.lastname: Billiar
authors.affiliation: Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, Mass.
authors.forename: Zheyang
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Department of Cardiology, Boston Children's Hospital, Department of Pediatrics, Harvard Medical School, Boston, Mass.
authors.forename: Tal
authors.initials: T
authors.lastname: Geva
mesh_terms: D000328:Adult; D019540:Area Under Curve; D001696:Biomechanical Phenomena; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D005260:Female; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008955:Models, Cardiovascular; D011237:Predictive Value of Tests; D011665:Pulmonary Valve Insufficiency / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D012372:ROC Curve; D020127:Recovery of Function; D013314:Stress, Mechanical; D013318:Stroke Volume; D013771:Tetralogy of Fallot / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome; D018497:Ventricular Dysfunction, Right / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D016278:Ventricular Function, Right; D020257:Ventricular Remodeling
keywords: computational modeling; congenital heart disease; pulmonary valve replacement; right ventricle; tetralogy of Fallot