title: Conformational pulsatile changes of the aortic annulus: impact on prosthesis sizing by computed tomography for transcatheter aortic valve replacement.
abstract: OBJECTIVE
  This study sought to investigate pulsatile changes of the aortic annulus and their impact on prosthesis selection by computed tomography (CT).
  
  
  BACKGROUND
  Precise noninvasive prosthesis sizing is a prerequisite for transcatheter aortic valve replacement.
  
  
  METHODS
  A total of 110 patients with severe aortic stenosis (mean age: 82.9 ± 8 years, mean aortic valve area: 0.69 ± 0.18 cm(2)) underwent electrocardiogram-gated CT. Aortic annulus dimensions were planimetrically quantified as area-derived diameter (D(A) = 2 ×✓(CSA/π), where CSA is the cross-sectional area) and perimeter-derived diameter (D(P) = P/π, where P is the length of the perimeter) in 5% increments of the RR interval. Hypothetical prosthesis sizing was based on D(A) and D(P) (23-mm prosthesis for <22 mm; 26 mm: 22 to 25 mm; 29 mm: >25 mm) and compared between maximum and traditional cardiac CT reconstruction phases at 35% and 75% of RR. Agreement for prosthesis selection was calculated by κ statistics.
  
  
  RESULTS
  D(A) and D(P) were increased and eccentricity was reduced during systole, with D(A-MAX) and D(P-MAX) most often observed at 20% of RR. D(P) was consistently larger than D(A). Average net differences were 2.0 ± 0.6 mm and 1.7 ± 0.5 mm by D(A-MIN) versus D(A-MAX) and D(P-MIN) versus D(P-MAX). Agreement for prosthesis sizing was found in 93 of 110 patients (κ = 0.75) by D(A-75%) and in 80 of 110 patients (κ = 0.53) by D(A-MAX) compared with D(A-35%); and in 94 of 110 patients (κ = 0.73) by D(P-75%) and in 93 of 110 patients (κ = 0.73) by D(P-MAX) compared with D(P-35%). With sizing by D(A-75%) or D(P-75%), nominal prosthesis diameter was smaller than D(A-MAX) or D(P-MAX) in 15 and 6 patients respectively.
  
  
  CONCLUSIONS
  Aortic annulus morphology exhibits conformational pulsatile changes throughout the cardiac cycle due to deformation and stretch. These changes affect prosthesis selection. Prosthesis selection by diastolic perimeter- or area-derived dimensions harbors the risk of undersizing.
authors.affiliation: Heart and Vascular Center, Medical University of South Carolina, Charleston, South Carolina 29401, USA. philipp.blanke@uniklinik-freiburg.de
authors.forename: Philipp
authors.initials: P
authors.lastname: Blanke
authors.forename: Maximillian
authors.initials: M
authors.lastname: Russe
authors.forename: Jonathon
authors.initials: J
authors.lastname: Leipsic
authors.forename: Jochen
authors.initials: J
authors.lastname: Reinöhl
authors.forename: Ullrich
authors.initials: U
authors.lastname: Ebersberger
authors.forename: Pal
authors.initials: P
authors.lastname: Suranyi
authors.forename: Matthias
authors.initials: M
authors.lastname: Siepe
authors.forename: Gregor
authors.initials: G
authors.lastname: Pache
authors.forename: Mathias
authors.initials: M
authors.lastname: Langer
authors.forename: U Joseph
authors.initials: UJ
authors.lastname: Schoepf
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D006328:Cardiac Catheterization / Q000295:instrumentation*; D055424:Cardiac-Gated Imaging Techniques; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D008297:Male; D018579:Patient Selection; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed