title: Impact of institutional volume and experience with CT interpretation on sizing of transcatheter aortic valves: A multicenter retrospective study.
abstract: BACKGROUND
  Computed tomography (CT) has become the standard imaging modality for pre-procedural aortic annular sizing prior to transcatheter aortic valve replacement (TAVR). We hypothesized that the accuracy of CT derived annular measurements would be greater at sites with higher TAVR procedural volume.
  
  
  METHODS
  Within a large integrated health system, TAVR was performed at low (<40 cases), intermediate (40-75 cases), and high-volume sites (>75 cases). 181 patients underwent TAVR with a Sapien XT transcatheter heart valve (THV). Two blinded experienced readers independently remeasured the annulus on CT and compared their measurements to site reported measurements. Hypothetical THV sizes were chosen based on measurements from site CT reports and independent readers' measurements, and compared to the implanted THV size.
  
  
  RESULTS
  Correlation between site reported measurements and independent readers measurements of mean annulus size varied between low-volume (r=0.31, p=0.18), intermediate-volume (r=0.34, p=0.01), and high-volume sites (r=0.96, p<0.01). On multivariate analysis, interpretation of ≥20 CT scans (OR 0.29; 95% CI 0.03-0.81; p 0.02) and high-volume site (OR 0.16; 95% CI 0.10-0.82; p 0.02) were associated with reduced mismatch between the site predicted THV size and independent readers predicted THV size. Mismatch between site predicted THV size and implanted THV size was associated with a worse 30-day composite of mortality, dialysis-dependent renal failure, cerebrovascular accident, new permanent pacemaker, and hospital readmission (55.3 vs. 38.7%; p=0.05).
  
  
  CONCLUSIONS
  Accuracy of CT aortic annular sizing is improved with higher individual experience and site TAVR volume. These findings should be confirmed in larger, prospective studies.
authors.affiliation: Cardiovascular Institute, Banner University Medical Center, Phoenix; Division of Interventional Cardiology, Banner University Medical Center, Phoenix.
authors.forename: Divya Ratan
authors.initials: DR
authors.lastname: Verma
authors.affiliation: Department of Radiology, Banner University Medical Center, Phoenix.
authors.forename: Yash
authors.initials: Y
authors.lastname: Pershad
authors.affiliation: Cardiovascular Institute, Banner University Medical Center, Phoenix; Division of Interventional Cardiology, Banner University Medical Center, Phoenix.
authors.forename: Ashish
authors.initials: A
authors.lastname: Pershad
authors.affiliation: Cardiovascular Institute, Banner University Medical Center, Phoenix; Division of Cardiothoracic Surgery, Banner University Medical Center, Phoenix.
authors.forename: Kenith
authors.initials: K
authors.lastname: Fang
authors.affiliation: Cardiovascular Institute, Banner University Medical Center, Phoenix; Department of Anesthesiology, Banner University Medical Center, Phoenix.
authors.forename: George
authors.initials: G
authors.lastname: Gellert
authors.affiliation: Cardiovascular Institute, Banner University Medical Center, Phoenix; Department of Radiology, Banner University Medical Center, Phoenix. Electronic address: mfmorris@mail.arizona.edu.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Morris
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000000981:diagnostic imaging*; D001130:Arizona; D006328:Cardiac Catheterization / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods / Q000401:mortality; D002983:Clinical Competence; D000072226:Computed Tomography Angiography; D018572:Disease-Free Survival; D005260:Female; D006349:Heart Valve Diseases / Q000000981:diagnostic imaging / Q000401:mortality / Q000628:therapy*; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods / Q000401:mortality; D061847:Hospitals, High-Volume; D061846:Hospitals, Low-Volume; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D015588:Observer Variation; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
keywords: Computed Tomography; Outcomes; TAVR