A Framework for the Systematic Characterization of the Aortic Valve Complex by Real-Time Three Dimensional Echocardiography: Implications for Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) has become a viable alternative to surgical aortic valve replacement in both high-risk and inoperable patients with symptomatic severe aortic stenosis [1]. A successful TAVR procedure is heavily dependent on appropriate patient selection and detailed morphologic characterization of the aortic valve complex to prevent device migration, coronary artery compromise and paravalvular leak. Two-dimensional echocardiography (2DE) and Doppler methods have traditionally been used to characterize the presence and severity of aortic stenosis [2]; however the detailed structural analysis of the aortic valve complex required for successful TAVR demands a more precise analysis of not only the aortic leaflets, but of the left ventricular outflow tract dimensions, aortic valve annulus, and the aortic root. Computed tomography (CT) [3, 4, 5, 6] and two dimensional transesophageal echocardiography (2D TEE) [7] are traditionally used to obtain this informa‐ tion. Although transthoracic and transesophageal three-dimensional echocardiography (3D Echo) provide detailed characterization of the aortic valve complex, these advanced modalities are not currently being routinely used in the evaluation of patients considered for TAVR. The purpose of this chapter is to provide a framework for the 3D echocardiographic evaluation of the aortic valve complex and its implications for TAVR.