New sutureless ‘atrial- mitral-valve prosthesis’ for minimally invasive mitral valve therapy

Incompetence is the most relevant dysfunction of the mitral valve. Surgical replacement and reconstruction is the treatment of choice whereas trans-catheter replacement or repair of mitral valve regurgitation proved demanding. We aimed for a new sutureless approach to anchor a biological heart valve in the mitral position without major surgery by inserting a valve-carrying hollow body into the left atrium. A mould representing the porcine left atrium from the pulmonary veins as far as the mitral valve was created. A superelastic Nitinol-skeleton was sutured onto a warp knitted tubular bifurcation of polyvinylidene fluoride (PVDF) multifilaments fitting the mould. This new self-expandable composite-material hollow body customized to the porcine anatomy was equipped with a commercially available biological heart valve. The functionality of this prosthesis was investigated in a circulatory mock loop simulator and the overall properties were examined in an open animal operation. The left atrium was incised and the prosthesis was placed in eight female pigs of 70 kg, under extracorporeal circulation. Prior to implantation, an artificial valve incompetence was created. Hemodynamic, echocardiographic, and radiological examinations were performed. A post mortem examination of the entire heart was performed. In the simulator we could demonstrate that the composite-material hollow body exhibited enough self-expansion to anchor onto the surrounding structures and that the function of the expanded valve was not compromised. In the animal, the prostheses walls almost completely adapted to surrounding structures leading to an exclusion of the left atrium. Sufficient treatment of mitral regurgitation was displayed hemodynamically and by echocardiography, although overall visualization was difficult. Therefore, in the last four animals a CT scan was performed demonstrating full expansion. Autopsy revealed an excellent anchorage of the prostheses. The relevant intracavitary injury and thrombotic formation were not seen. By the use of a composite-material self-expanding hollow body it is possible exclude a complete heart chamber and thereby to anchor a biological heart valve without sutures.