A new approach to interventional atrioventricular valve therapy

Objective: Transcatheter replacement or repair of mitral valve regurgitation has proved demanding. We aimed for a new approach to anchor a biologic heart valve in the mitral position by inserting a valve-carrying hollow body into the left atrium. This approach was investigated in both a simulation and an animal model. Methods: After creating a mold representing the porcine left atrium from the pulmonary veins as far as the mitral valve, a nitinol skeleton was sutured onto interlaced yarns of polyvinylidene flouride fitting the mold. The resulting device was equipped with a commercially available stentless valve (25 mm) and investigated in a simulator regarding basic functionality. Furthermore, the device was implanted in 8 female pigs through incision of the left atrium during extracorporeal circulation. Before implantation, artificial regurgitation was created by means of excision from the posterior mitral leaflet. Hemodynamic, echocardiographic, and radiologic examinations followed. For a postmortem examination, the entire heart and the lungs were excised. Results: We could demonstrate the functionality of the heart valve in a complex, collapsible, and self-expanding hollow body. The device adapted to the surrounding structures, leading to an exclusion of the left atrium. Sufficient treatment of mitral regurgitation was monitored hemodynamically and by means of echocardiographic analysis, although overall visualization remained difficult. Therefore in 4 animals computed tomographic scans were performed. Autopsy revealed proper positioning without major trauma to the surrounding structures. Conclusion: Anchoring an additional heart valve in the atrioventricular position does not necessarily need to be performed in the heart valve structure itself. Placement of an additional valve in the mitral position is feasible through this approach. (J Thorac Cardiovasc Surg 2010;140:97-102)