title: Stent fracture, valve dysfunction, and right ventricular outflow tract reintervention after transcatheter pulmonary valve implantation: patient-related and procedural risk factors in the US Melody Valve Trial.
abstract: BACKGROUND
  Among patients undergoing transcatheter pulmonary valve (TPV) replacement with the Melody valve, risk factors for Melody stent fracture (MSF) and right ventricular outflow tract (RVOT) reintervention have not been well defined.
  
  
  RESULTS
  From January 2007 to January 2010, 150 patients (median age, 19 years) underwent TPV implantation in the Melody valve Investigational Device Exemption trial. Existing conduit stents from a prior catheterization were present in 37 patients (25%, fractured in 12); 1 or more new prestents were placed at the TPV implant catheterization in 51 patients. During follow-up (median, 30 months), MSF was diagnosed in 39 patients. Freedom from a diagnosis of MSF was 77±4% at 14 months (after the 1-year evaluation window) and 60±9% at 39 months (3-year window). On multivariable analysis, implant within an existing stent, new prestent, or bioprosthetic valve (combined variable) was associated with longer freedom from MSF (P<0.001), whereas TPV compression (P=0.01) and apposition to the anterior chest wall (P=0.02) were associated with shorter freedom from MSF. Freedom from RVOT reintervention was 86±4% at 27 months. Among patients with a MSF, freedom from RVOT reintervention after MSF diagnosis was 49±10% at 2 years. Factors associated with reintervention were similar to those for MSF.
  
  
  CONCLUSIONS
  MSF was common after TPV implant in this multicenter experience and was more likely in patients with severely obstructed RVOT conduits and when the TPV was directly behind the anterior chest wall and/or clearly compressed. A TPV implant site protected by a prestent or bioprosthetic valve was associated with lower risk of MSF and reintervention.
authors.affiliation: Department of Cardiology, Children’s Hospital, 300 Longwood Ave., Boston, MA 02115, USA. doff.mcelhinney@cardio.chboston.org
authors.forename: Doff B
authors.initials: DB
authors.lastname: McElhinney
authors.forename: John P
authors.initials: JP
authors.lastname: Cheatham
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Jones
authors.forename: James E
authors.initials: JE
authors.lastname: Lock
authors.forename: Julie A
authors.initials: JA
authors.lastname: Vincent
authors.forename: Evan M
authors.initials: EM
authors.lastname: Zahn
authors.forename: William E
authors.initials: WE
authors.lastname: Hellenbrand
mesh_terms: D000293:Adolescent; D000328:Adult; D006328:Cardiac Catheterization / Q000009:adverse effects / Q000379:methods; D002648:Child; D004868:Equipment Failure; D006349:Heart Valve Diseases / Q000175:diagnosis / Q000628:therapy; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000379:methods*; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D015999:Multivariate Analysis; D011664:Pulmonary Valve / Q000503:physiopathology*; D012189:Retrospective Studies; D012307:Risk Factors; D015607:Stents; D013771:Tetralogy of Fallot / Q000175:diagnosis / Q000628:therapy; D014188:Transposition of Great Vessels / Q000175:diagnosis / Q000628:therapy; D014481:United States; D014694:Ventricular Outflow Obstruction / Q000453:epidemiology* / Q000503:physiopathology; D055815:Young Adult