A novel transcatheter aortic valve with a form-fitting anchor for self-alignment: feasibility in a chronic preclinical model.

Abstract

Our goal was to assess the viability of an alternative anchoring design for a transcatheter aortic valve based on a form-fitting principle with a self-expanding nitinol frame to reduce issues related to excess radial force. A 26-mm outer diameter prototype of a self-expanding nitinol frame was developed to reduce the amount of necessary radial force by utilizing additional anchoring via protruding arms in each aortic sinus, thus allowing for a form-fitting principle as well as the coaxial self-alignment of the valve inside the native anatomy. The prototype valve was implanted via a transapical approach in the orthotopic position in 2 sheep. Follow-up examinations were performed at regular intervals during a 3-month period to confirm adequate function and anchoring. Observation demonstrated secure, facilitated positioning with perfect alignment of the stent in the aortic sinuses. Repeated transthoracic echocardiography showed adequate valve function over the entire period with no change in the valve position, gradients or regurgitation. The animals remained in sinus rhythm during the entire period. The prototype frame with its form-fitting properties has the potential to resolve issues related to malpositioning and excess radial force for transcatheter aortic valves as well as to extend the treatment possibilities to pure aortic insufficiencies. The stent is presently being tested in vitro for its long-term durability.