Feasibility and accuracy of three-dimensional transthoracic echocardiography vs. multidetector computed tomography in the evaluation of aortic valve annulus in patient candidates to transcatheter aortic valve implantation.

AIMS: Proper measurement of the aortic annulus (AoA) is crucial for the success of transcatheter aortic valve implantation (TAVI). Transthoracic echocardiography (TTE) is the first step to assess AoA diameter, but a two-dimensional TTE (2DTTE) measurement is no longer accepted as the sole determinant of prosthetic size. The aims of the study were to evaluate feasibility and accuracy of three-dimensional TTE (3DTTE) estimation of AoA dimensions in comparison with multidetector computer tomography (MDCT).

METHODS AND RESULTS: We enrolled 100 consecutive patients referred for TAVI. Feasibility of AoA evaluation was 91% for 3DTTE and in 90% for MDCT. In 81 of 100 patients, AoA maximum diameter (max-D), minimum diameter (min-D), and area were measured and compared using 2DTTE, 3DTTE, and MDCT. Image quality of 3DTTE was sufficient in 47, good in 46 and optimal in 7%. High correlations (P < 0.001) were found between MDCT and 3DTTE (max-D: r = 0.89; min-D r = 0.86; area: r = 0.93), and between MDCT and 2DTTE (min-D: r = 0.81; area 0.78). The 3DTTE measurements were found to be highly reproducible on intra- and interobserver variability analyses. Regarding the choice of prosthesis size, agreement between 3DTTE and MDCT was very good (k = 0.84, P < 0.001) while it was poor between 2DTTE and MDCT (k = 0.36, P < 0.001).

CONCLUSIONS: 3DTTE may be a valid imaging alternative in patients unsuitable for MDCT during the preoperative evaluation for TAVI. Evaluation of AoA through 3DTTE is feasible, and measurements closely approximate those of MDCT thus improving TTE accuracy in identifying the correct prosthesis size.