title: Computed tomography-based sizing recommendations for transcatheter aortic valve replacement with balloon-expandable valves: Comparison with transesophageal echocardiography and rationale for implementation in a prospective trial.
abstract: BACKGROUND
  Computed tomography (CT) annular measurements are predictive of paravalvular regurgitation after transcatheter aortic valve replacement (TAVR) which is a predictor of mortality and morbidity.
  
  
  OBJECTIVE
  To demonstrate the rationale and potential implications of new CT sizing recommendations for TAVR.
  
  
  METHODS
  The CT sizing recommendations aim to ensure routine transcatheter heart valve (THV) oversizing of the aortic annular area [(THV external area/systolic annular area - 1) × 100; range, 1%-20%; target, 10%-15%]. Consecutive patients (n = 120) underwent CT before TAVR with balloon-expandable valves sized by transesophageal echocardiography (TEE). Retrospectively, the CT-recommended THV size was compared with the actual size implanted.
  
  
  RESULTS
  Compared with TEE, application of the newly developed CT-based sizing recommendations would have led to implantation of a larger valve in 33.3% (40/120), no change in valve size in 55.8% (67/120), and a smaller valve in 10.8% (13/120). In patients when CT recommended a larger valve, the incidence of at least moderate paravalvular regurgitation was 25% (10/40) compared with 4.5% (3/67; P < 0.01) when both TEE and CT recommendations were in agreement. Using diastolic versus systolic CT measurements results in 20% of patients receiving smaller THVs. TEE sizing resulted in 33.3% (40/120) of valves being undersized (THV area < CT systolic annular area) with a mean annular oversizing of 9.4% ± 17.4% (range: -21.5% to 65.9%) without annular rupture. In contrast, the CT sizing recommendations results in mean annular oversizing of 13.9% ± 8.0% (range, 1.3%-29.8%).
  
  
  CONCLUSIONS
  These CT sizing recommendations enable standardized moderate overexpansion of the aortic annulus. Clinical outcomes from these recommendations are being prospectively assessed in a multicenter trial.
authors.affiliation: St Paul's Hospital, University of British Columbia, 1081 Burrard St, Vancouver, BC, Canada V6Z 1Y6.
authors.forename: Alexander B
authors.initials: AB
authors.lastname: Willson
authors.forename: John G
authors.initials: JG
authors.lastname: Webb
authors.forename: Melanie
authors.initials: M
authors.lastname: Freeman
authors.forename: David A
authors.initials: DA
authors.lastname: Wood
authors.forename: Ronen
authors.initials: R
authors.lastname: Gurvitch
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Thompson
authors.forename: Robert R
authors.initials: RR
authors.lastname: Moss
authors.forename: Stefan
authors.initials: S
authors.lastname: Toggweiler
authors.forename: Ronnie K
authors.initials: RK
authors.lastname: Binder
authors.forename: Bradley
authors.initials: B
authors.lastname: Munt
authors.forename: Anson
authors.initials: A
authors.lastname: Cheung
authors.forename: Cameron
authors.initials: C
authors.lastname: Hague
authors.forename: Jian
authors.initials: J
authors.lastname: Ye
authors.forename: Jonathon A
authors.initials: JA
authors.lastname: Leipsic
mesh_terms: D000369:Aged, 80 and over; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000601:surgery; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D062906:Cardiac Catheters; D002986:Clinical Trials as Topic; D017548:Echocardiography, Transesophageal / Q000379:methods*; D005260:Female; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D006801:Humans; D008297:Male; D018579:Patient Selection; D011300:Preoperative Care / Q000379:methods; D011474:Prosthesis Design; D017755:Prosthesis Fitting; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*