['Successful transcatheter aortic valve implantation (TAVI) mandates comprehensive, accurate multimodality imaging. Echocardiography is involved at all key stages and, with the advent of real-time three-dimensional (3D) transesophageal echocardiography, is uniquely placed to enable periprocedural monitoring. The investigators describe a comprehensive two-dimensional (2D) and 3D echocardiographic protocol, and the additional benefits of 3D TEE, within a high-volume TAVI program.', 'TAVI was performed with 2D and 3D transesophageal echocardiographic and fluoroscopic guidance in consecutive high-risk patients with symptomatic severe aortic stenosis. The role of TEE, including the additive value of 3D TEE, was examined, and procedural and echocardiographic outcomes were evaluated. A 3D sizing transcatheter heart valve (THV) strategy was used, except as mandated by study protocol.', 'Procedural success was achieved in 99% of 256 patients (mean age, 82.9 ± 7.1 years, mean logistic European System for Cardiac Operative Risk Evaluation score, 21.6 ± 11.2%; mean aortic valve area, 0.63 ± 0.19 cm(2)), with no procedural deaths. Acceptable 2D and 3D transesophageal echocardiographic images were achieved in all patients. Aortic valve annular dimensions by 2D transthoracic echocardiography, 2D TEE, and 3D TEE were 21.6 ± 1.9 mm, 22.5 ± 2.2 mm (P < .001), and 23.0 ± 2.0 mm (P = .004 vs 2D TEE), respectively. The 2D THV sizing strategy would have changed THV selection in 23% of patients, downsizing in most. Three-dimensional TEE provided superior spatial visualization and anatomic orientation and optimized procedural performance. Postprocedural mild, moderate, and severe paravalvular aortic regurgitation was observed in 24%, 3%, and 0% of patients, respectively, with no or trace transvalvular aortic regurgitation in 95%. A second valve was successfully deployed in five patients, and TEE detected five other periprocedural complications.'] Does real-time three-dimensional transesophageal echocardiography add value to transcatheter aortic valve implantation?