title: A method to determine suitable fluoroscopic projections for transcatheter aortic valve implantation by computed tomography.
abstract: BACKGROUND
  In transcatheter aortic valve implantation (TAVI), optimal selection of fluoroscopic projections that permit orthogonal visualization of the aortic valve plane is important but may be difficult to achieve.
  
  
  OBJECTIVE
  We developed and validated a simple method to predict suitable fluoroscopic projections on the basis of cardiac CT datasets.
  
  
  METHODS
  In 75 consecutive patients that underwent TAVI, angulations in which a 35-mm thick maximum intensity projection would render all aortic valve calcium into 1 plane were determined by manual interaction with contrast-enhanced dual-source CT datasets. TAVI operators used the predicted angulation for the first aortic angiogram and performed additional aortic angiograms if no satisfactory view of the aortic valve plane was obtained. Predicted angulations were compared with the angulation used for valve implantation. Radiation exposure and contrast use was compared between patients with accurate prediction of fluoroscopic angulations by CT and patients in whom CT failed to predict a suitable view.
  
  
  RESULTS
  The mean difference between the predicted angulation according to CT and the angulation used for implantation was 3 ± 6 degrees. CT predicted a suitable angulation (<5-degree deviation) in 63 of 75 cases (84%). The mean number of aortic angiograms acquired in patients with correct prediction (1.02 ± 0.1) was significantly lower than in patients with incorrect prediction of the implantation angle by CT (3.0 ± 1.7; P < 0.001). Contrast agent required for the entire TAVI procedure was lower in patients with correct prediction (72 ± 36 mL vs 106 ± 39 mL; P = 0.001).
  
  
  CONCLUSIONS
  CT permits prediction of suitable angulations for TAVI in most cases.
authors.affiliation: Department of Cardiology, University of Erlangen-Nürnberg, Ulmenweg 18, 91054 Erlangen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Arnold
authors.forename: Stephan
authors.initials: S
authors.lastname: Achenbach
authors.forename: Ina
authors.initials: I
authors.lastname: Pfeiffer
authors.forename: Stephan
authors.initials: S
authors.lastname: Ensminger
authors.forename: Mohamed
authors.initials: M
authors.lastname: Marwan
authors.forename: Friedrich
authors.initials: F
authors.lastname: Einhaus
authors.forename: Tobias
authors.initials: T
authors.lastname: Pflederer
authors.forename: Dieter
authors.initials: D
authors.lastname: Ropers
authors.forename: Annika
authors.initials: A
authors.lastname: Schuhbaeck
authors.forename: Katharina
authors.initials: K
authors.lastname: Anders
authors.forename: Michael
authors.initials: M
authors.lastname: Lell
authors.forename: Michael
authors.initials: M
authors.lastname: Uder
authors.forename: Josef
authors.initials: J
authors.lastname: Ludwig
authors.forename: Michael
authors.initials: M
authors.lastname: Weyand
authors.forename: Werner G
authors.initials: WG
authors.lastname: Daniel
authors.forename: Richard
authors.initials: R
authors.lastname: Feyrer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D006328:Cardiac Catheterization / Q000379:methods*; D005260:Female; D005471:Fluoroscopy / Q000379:methods*; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000379:methods*