Multimodal assessment of the aortic annulus diameter: implications for transcatheter aortic valve implantation

Objectives: We sought to compare 3 methods of measurements of the aortic annulus, transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), and multislice computed tomography (MSCT), and to evaluate their potential clinical impact on transcatheter aortic valve implantation (TAVI) strategy.

Background: Exact measurement of the aortic annulus is critical for a patient's selection and successful implantation.

Methods: Annulus diameter was measured using TTE, TEE, and MSCT in 45 consecutive patients with severe aortic stenosis referred for TAVI. The TAVI strategy (decision to implant and choice of the prosthesis' size) was based on manufacturer's recommendations (Edwards-Sapien prosthesis, Edwards Lifesciences, Inc., Irvine, California).

Results: Correlations between methods were good but the difference between MSCT and TTE (1.22 +/- 1.3 mm) or TEE (1.52 +/- 1.1 mm) was larger than the difference between TTE and TEE (0.6 +/- 0.8 mm; p = 0.03 and p < 0.0001, respectively). Regarding TAVI strategy, agreement between TTE and TEE overall was good (kappa = 0.68), but TAVI strategy would have been different in 8 patients (17%). Agreement between MSCT and TTE or TEE was only modest (kappa = 0.28 and 0.27), and a decision based on MSCT measurements would have modified the TAVI strategy in a large number of patients (40% to 42%). Implantation, performed in 34 patients (76%) based on TEE measurements, was successful in all but 1 patient with grade 3/4 regurgitation.

Conclusions: In patients referred for TAVI, measurements of the aortic annulus using TTE, TEE, and MSCT were close but not identical, and the method used has important potential clinical implications on TAVI strategy. In the absence of a gold standard, a strategy based on TEE measurements provided good clinical results.