A Concept for a Novel Type of Mitral Valve Prosthesis

Background: Hearth valve prostheses for the mitral position need a counterpoint for the fixation of the cusps, as do methods for mitral valve reconstructions. The varying distance between the cusps and the possible fixation zone in the atrial wall complicates the selection of the right artificial cord length. At the 35th EACTS meeting a concept of adding a stirrup to an annuloplasty ring was presented using it as a well-defined fixation bar for the cords during mitral valve repair. Here, we propose a concept for a mitral valve prosthesis that can be sutured in a preexisting annuloplasty ring.

Method: The host structure was constructed from discarded annuloplasty rings and metal wire. A 3D modeling software was used to design .stl files of the cusp structure including cords and a suture zone for the fixation to the ring. Prototypes were printed in silicone of shore hardness 35 using a specialized 3D printer. Preliminary hemodynamic testing was performed in a hemodynamic pulse duplicator, mimicking an aortic heart beat profile at 70 bpm with 70 mL stroke volume. Regurgitation fraction and mean systolic pressure gradient were measured and compared with a current biological and mechanical valve.

Results: The design and printing process allowed for a rapid development and testing of various modifications resulting in a working prototype. First hemodynamic testing revealed promising systolic pressure gradients (13.22 ± 0.81 mm Hg) compared with currently used biological (8.18 ± 0.87 mm Hg) or mechanical (10.53 ± 0.60 mm Hg) prostheses. The regurgitation fraction (68.71%) remains the main problem still to be addressed.

Conclusion: Our prototype serves as a proof of concept for a potential prosthetic mitral valve. Furthermore, it should be possible to install it into a preexisting, modified annuloplasty ring after removal of the natural cusps. Depending on the biocompatibility of future 3D-printable flexible polymers rapid production is possible. Alternatively, this valve type might be manufactured from patient pericardium using a cut-out stencil.

Publication History

Article published online:
28 January 2023