title: Prevention and management of transcatheter balloon-expandable aortic valve malposition.
abstract: OBJECTIVE
  Early clinical outcomes in selected high-risk patients undergoing catheter-based aortic valve replacement (AVR) compare favorably with conventional surgical AVR. Improved understanding of the mechanisms of success and failure of transcatheter AVR will likely improve outcomes further. To this end, we examined our experience during the developmental phases of transcatheter AVR and describe the causes and management of prosthetic valve malposition.
  
  
  METHODS
  Transcatheter balloon-expandable AVR was performed in 170 patients at two centers. Malposition was defined as prosthetic valve implantation in a location other than within the native valve. Patients were prospectively identified and followed as part of an ongoing database.
  
  
  RESULTS
  Valve malposition occurred in 9 of 170 patients (5.3%). Final position was supravalvular in eight of nine cases. In all cases, embolization to the ascending aorta occurred within a few cardiac cycles following deployment. Importantly, late embolization was not observed. In most cases, the prosthesis was uneventfully repositioned in the more distal aorta. Positioning was subvalvular in one patient (0.6%), resulting in a severe regurgitation with residual native valve stenosis. Implantation of a second transcatheter valve was attempted in six patients and was successful in all. Conventional AVR was performed in two patients, with early mortality in one. At late follow-up (mean 412 days), seven of nine patients remain alive (78%) with a functioning prosthesis and relief of aortic stenosis.
  
  
  CONCLUSIONS
  Malposition of current balloon-expandable aortic valves is a largely preventable complication. An improved understanding of the procedure will likely minimize this possibility and mitigate the consequences should malposition occur.
authors.affiliation: Division of Cardiology, St. Paul's Hospital, University of British Columbia, Vancouver, Canada.
authors.forename: Abdullah M
authors.initials: AM
authors.lastname: Al Ali
authors.forename: Lukas
authors.initials: L
authors.lastname: Altwegg
authors.forename: Eric M
authors.initials: EM
authors.lastname: Horlick
authors.forename: Christopher
authors.initials: C
authors.lastname: Feindel
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Thompson
authors.forename: Anson
authors.initials: A
authors.lastname: Cheung
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Carere
authors.forename: Karin
authors.initials: K
authors.lastname: Humphries
authors.forename: Jian
authors.initials: J
authors.lastname: Ye
authors.forename: Jean-Bernard
authors.initials: JB
authors.lastname: Masson
authors.forename: John G
authors.initials: JG
authors.lastname: Webb
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging / Q000628:therapy*; D002170:Canada; D006328:Cardiac Catheterization / Q000009:adverse effects* / Q000295:instrumentation; D002404:Catheterization / Q000009:adverse effects* / Q000295:instrumentation; D020878:Device Removal; D005548:Foreign-Body Migration / Q000000981:diagnostic imaging / Q000209:etiology / Q000401:mortality / Q000517:prevention & control / Q000628:therapy*; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects* / Q000295:instrumentation; D006801:Humans; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D015641:Radiography, Interventional; D013997:Time Factors; D016896:Treatment Outcome