Transcatheter aortic valve implantation. Role of imaging

Abstract

Transcatheter aortic valve implantation (T-AVI) has shown good results in high-risk patients with severe aortic stenosis. Throughout the whole process of T-AVI, different imaging modalities are indispensable. Preoperatively, multislice computed tomography, angiography and transesophageal echo (TEE) are utilized for patient selection, valve selection, approach selection and the planning of implant placement. Intraoperatively, angiography and TEE are used for controlling placement of the guidewire and valve positioning. Quality control and follow-up require TEE imaging and can require additional CT or angiography studies. In the first half of this paper, we discuss the applicability of different imaging modalities for T-AVI in the light of the current best practice. In the second half of this paper, we present an overview on research projects in medical engineering which aim at development of image-based methods for increasing patient safety during T-AVI. Template-based implantation planning, as it is applied in dental, orthopedic and other surgical disciplines, is proposed as an aid during implant selection in order to help reduce the incidence of complications such as atrioventricular node block and paravalvular leaks. Current research tries to apply state-of-the-art engineering techniques, such as computational fluid dynamics to optimize valve selection and positioning. For intraoperative assistance during valve positioning, real-time image processing methods are proposed to track target landmarks and the stented valve.