A novel stent for percutaneous heart valve implantation: first in vitro results

Percutaneous aortic valve implantation has become an alternative technique to surgical valve replacement in patients with high risk for surgery. This technique is at its beginning and stents used for valve prostheses remain standard vascular stents. These stents are, however, not designed to undergo heart valve stress. They do not match the aortic environment geometry, and induce exaggerated tissue traumatism. Reduced implant lifetime may therefore be expected. The purpose of the present work is to evaluate in vitro the technical feasibility of noninvasive aortic valve replacement with a novel more specific stent. This stent is especially adapted to its implantation environment with a design that matches the shape of the aortic root while respecting the valve functions. We present a design, a manufacturing process and in vitro performances for the stent under static pressure loading and pulsatile flow. The stent shows good dynamic behavior in keeping position imposed at implantation time and in matching the aortic root dimensions changes. Prosthesis static and dynamic regurgitation are evaluated and show values close to those obtained with other commercially available prostheses.