Current developments in transcatheter aortic valve implantation techniques.

Transcatheter aortic valve implantation (TAVI) has become a viable treatment option in high-risk patients with symptomatic aortic stenosis. The widespread uses of TAVI procedures in recent years and the steadily growing evolution of numerous new catheter-based devices have led to a remarkable shift in the treatment of this patients group towards TAVI procedures. Several developments have now overcome most of the initial problems with the early devices and have been quickly implemented in clinical routine. Nevertheless, several current TAVI systems have shown a number of limitations and disadvantages relating to valve design, the occurrence of paravalvular leakages, valve positioning and deployment, the occurrence of thromboembolic events during the procedure, as well as vascular or conduction complications. As a result, all current efforts in further development focus primarily on the following issues: (1) the further miniaturization of catheter devices and sheaths not only to facilitate transarterial but also transapical access; (2) the development of a broad variety of valve sizes to cover all aortic annulus sizes; (3) the development of retrievable, repositionable and removable systems; (4) the development or modification of stent design to prevent or reduce paravalvular leakages; (5) the implementation of modern imaging and navigation tools; (6) and finally, the initial development of prophylactic devices to prevent thromboembolic events. The present article provides a review of current developments in the field of TAVI.