Abstract 17437: Distribution of Aortic Annulus Dimensions in Patients Referred for Cardiac Computed Tomography Prior to Transcatheter Aortic Valve Implantation

Abstract

Background: Accurate sizing of prostheses for TAVI is crucial to avoid complications such as prosthesis migration or paravalvular regurgitation. Providing measurements of the aortic annulus in any arbitrary plane with high spatial resolution, Multi Detector-Computed Tomography is uniquely suited to assess aortic annulus dimensions. So far, the normal distribution of aortic annulus dimensions in TAVI candidates has not been described, but would be important for device development.

Methods: Forty six consecutive patients (16 male, mean age 83±6y) underwent ECG-gated Dual Source-Computed Tomography as part of a routine planning procedure for TAVI. In oblique multiplanar reconstructions aligned with the aortic annulus plane, long axis and short axis diameter of the aortic annulus as well as annulus area and circumference were manually assessed.

Results: For all patients the aortic annulus was ovally shaped. The mean long axis diameter was 25±2mm (median 25mm, range 20-32mm), the mean short axis diameter was 21±2mm (median 20mm, range 17-26mm). Both diameters were significantly larger for men than for women (p=0.003 for long axis and p=0.005 for short axis diameter). Mean aortic annulus area was 4.5±1cm2 (median 4.2cm2, range 3.0-7.4cm2) for the overall group, being significantly larger for men than for women (mean 5.2±1.1cm2 vs. 4.1±0.7cm2, p=0.0003). The mean circumference of the aortic annulus was 7.5±0.8cm for all patients. There was no significant difference between men and women (mean 7.8±1.2cm vs. 7.4±0.6cm, p=0.12). Frequency distributions of all parameters for the overall patient series are given in the figure, illustrating that only small annulus diameters were normally distributed.

Conclusion: Assessment of the aortic annulus using Computed Tomography prior to TAVI yields specific values for annulus diameters, area and circumference. These values are mostly gender-related, even though they are predominantly not normally distributed.