title: A Strategy of Underexpansion and Ad Hoc Post-Dilation of Balloon-Expandable Transcatheter Aortic Valves in Patients at Risk of Annular Injury: Favorable Mid-Term Outcomes.
abstract: OBJECTIVE
  The aim of this study was to evaluate a strategy of intentional underexpansion of excessively oversized balloon-expandable transcatheter heart valves (THVs) in terms of clinical outcomes, valve function, and frame durability at 1 year.
  
  
  BACKGROUND
  Transcatheter aortic valve replacement requires the selection of an optimally sized THV to ensure paravalvular sealing and fixation without risking annular injury. However, some patients have "borderline" annular dimensions that require choosing between a THV that may be too small or another that may be too large.
  
  
  METHODS
  We evaluated 47 patients at risk of annular injury who underwent transcatheter aortic valve replacement (TAVR) with an oversized, but deliberately underexpanded, THV followed by post-dilation if required. Clinical evaluation, echocardiography, and cardiac computed tomography were performed pre-TAVR, post-TAVR, and at 1 year.
  
  
  RESULTS
  Deployment of oversized THVs with modest underfilling of the deployment balloon (<10% by volume) was not associated with significant annular injury. Paravalvular regurgitation was mild or less in 95.7% of patients, with post-dilation required in 10.7%. THV hemodynamic function was excellent and remained stable at 1 year. Computed tomography documented stent frame circularity in 87.5%. Underexpansion was greatest within the intra-annular THV inflow (stent frame area 85.8% of nominal). There was no evidence of stent frame recoil, deformation, or fracture at 1 year.
  
  
  CONCLUSIONS
  In carefully selected patients with borderline annulus dimensions and in whom excessive oversizing of a balloon-expandable SAPIEN XT valve (Edwards Lifesciences, Inc., Irvine, California) is a concern, a strategy of deliberate underexpansion, with ad hoc post-dilation, if necessary, may reduce the risk of annular injury without compromising valve performance.
authors.affiliation: St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: John S
authors.initials: JS
authors.lastname: Tan
authors.affiliation: St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: Jonathon
authors.initials: J
authors.lastname: Leipsic
authors.affiliation: St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: Gidon
authors.initials: G
authors.lastname: Perlman
authors.affiliation: St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: Dion
authors.initials: D
authors.lastname: Stub
authors.affiliation: St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: Danny
authors.initials: D
authors.lastname: Dvir
authors.affiliation: Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Nicolaj C
authors.initials: NC
authors.lastname: Hansson
authors.affiliation: Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Bjarne L
authors.initials: BL
authors.lastname: Norgaard
authors.affiliation: St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: Philipp
authors.initials: P
authors.lastname: Blanke
authors.affiliation: St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: Anson
authors.initials: A
authors.lastname: Cheung
authors.affiliation: St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: Jian
authors.initials: J
authors.lastname: Ye
authors.affiliation: St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Thompson
authors.affiliation: St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: Robert R
authors.initials: RR
authors.lastname: Moss
authors.affiliation: St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: Sandra
authors.initials: S
authors.lastname: Lauck
authors.affiliation: St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Wood
authors.affiliation: St. Paul's Hospital, Vancouver, British Columbia, Canada. Electronic address: webb@providencehealth.bc.ca.
authors.forename: John
authors.initials: J
authors.lastname: Webb
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000293:injuries / Q000503:physiopathology; D001022:Aortic Valve Insufficiency / Q000209:etiology / Q000517:prevention & control; D001024:Aortic Valve Stenosis / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D063126:Balloon Valvuloplasty / Q000009:adverse effects / Q000379:methods*; D006328:Cardiac Catheterization / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006335:Heart Injuries / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D018579:Patient Selection; D011474:Prosthesis Design; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014463:Ultrasonography
keywords: aortic valve; sizing; transcatheter aortic valve replacement