Comparative Study Of 3 Imaging Modalities For The Accuracy Of Evaluating Aortic Annulus Diameter

Objective:To compare three commonly used imaging modalities:intracardiac echocardiography (ICE), transthoracic echocardiography (TTE) and multiple slice CT (MSCT) in measurement of aortic annulus diameter of Chinese miniature pigs.Determine the best means for prediction of prosthetic valve size for transcatheter aortic valve implantation.Method:Aortic annulus diameters of 12 Chinese miniature pigs were measured using MSCT, TTE and ICE respectively. Accuracy and consistency of eachmethodwere compared, as well as their predictions in size choosing of transcatheter valves.Results:Mean aortic annulus diameter were23.69±0.83 mm (ICE),22.91±1.11 mm (TTE), 23.81±0.76 mm (MSCT). Analysis of Variance showed significant differences with each other(F=10.51,p=0.006), Bonferroni’s test showed there was no significant differences between MSCT and ICE, but TTE had significant differences with TTE and ICE. However, the Bland-Altmananalysis indicated that there was a tendency for underestimation using TTE in aortic annulus measurementswhen compared with MSCT. This was not happened in ICE(ICE VS MSCT, mean difference:-0.12 mm, limits of agreement:-0.49-0.25 mm; TTE VS MSCT, mean difference:-0.91mm, limits of agreement:-2.78-0.97mm; TTE VS ICE mean difference:-0.78 mm, limits of agreement:-2.4-0.86 mm;). When usingthese three measurementsfor prediction of the size of transcatheter valves, ICE showed good consistency with MSCT (kappa= 1.000). In contrast, the valve sizes decided by TTE were smaller than that decided by MSCT in 33.3%(4/12) of the tested animals.Conclusion:Compared with TTE, ICE demonstrated a higher consistency with MSCT measurement, indicating that it can be used for prediction of prosthetic valve size.TTE, which is nowadays commonly used in clinical practice, has a tendency to underestimate the diameter of the aortic annulus, and cause a small size of the prosthetic valve in certain TAVI strategy.