Percutaneous transcatheter aortic valve implantation: present and future perspective

Transcatheter aortic-valve implantation is becoming the standard of care for inoperable patients with severe aortic stenosis and a valid alternative for those at high surgical risk. Since the first percutaneous transcatheter aortic-valve implantation in humans in 2002, over 50,000 transcatheter aortic valves have been implanted in the last decade, with progressive improvement in the available devices. Overall, there are two main families of transcatheter prosthesis: self-expandable and nonself-expandable. The self-expandable devices, for which CoreValve(®) (Medtronic CV Luxembourg S.a.r.l., Luxembourg) represents the prototype, are characterized by a structure composed of shape memory materials, usually nitinol, which acquire its final shape once released. By contrast, the non-self-expandable prostheses, mainly represented by the Edwards(®) valve (Edwards Life Sciences, Inc., CA, USA), require balloon dilatation to reach its final shape. Although several publications have already provided positive data on both technologies, new clinical studies with improved systems are currently being conducted in order to provide more solid data and potentially expand the spectrum of patients who can benefit from this therapy. Thus, the aim of the present paper is to review the salient features of the two most used systems today (third-generation CoreValve and Edwards SAPIEN XT(®)) as well as to provide data on other emerging valves and future perspectives.