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This pre-clinical study was aimed to evaluate the safety and feasibility of transcatheter mitral valve implantation using a novel designed Mithos valve (NewMed Medical Co., Ltd., Shanghai, China) in a porcine model.
The Mithos valve is a self-expanding bioprosthesis with cross-linked bovine pericardial tissue tricuspid leaflets mounted inside a nitinol self-expanding frame designed for transcatheter mitral valve implantation. By using porcine animal models, Mithos valve was implanted through a transapical approach. Technical feasibility, safety, durability and function of the Mithos valve were evaluated with autopsy of explanted heart, ventriculography, intracardiac echocardiography (ICE), transthoracic echocardiography (TTE), multi-sliced CT (MSCT), histological and electron microscopic examinations in acute study and six months following the procedure.
Animal study of 26 swine demonstrated procedural success of 100%. Macroscopic evaluation of the explanted hearts demonstrated stable and secured positioning of the transcatheter valve, with full endothelialization of the valve leaflets and fabric coatings. Multi-modality image studies including ventriculography, ICE, TTE, and MSCT showed excellent function and alignment of the valves, without coronary artery obstruction, left ventricular outflow tract obstruction, transvalvular gradients or obvious paravalvular leak. There was 7 mild-to-moderate degree of paravalvular leaks and no significant mitral regurgitation. Cardioscopy and macroscopic evaluation demonstrated stable and secure positioning of the Mithos valve without evidence of injury to the ventricular or atrial walls. Histological and electron microscopic examinations showed no obvious macro- or micro-calcification up at the 6-month follow-up.
Transcatheter mitral valve implantation using with Mithos valve is technically safe and feasible in pre-clinical studies, resulting in a stable and well-functioning mitral bioprosthesis. With a better understanding of preclinical knowledge, patient selection criteria and first-in-human studies will be addressed.