Evaluation of an Innovative Device for Mitral Valve Regurgitation: Experimental Acute In Vivo Results

Abstract

Objective: Currently, mitral prosthetic rings are intended only to reshape the annulus. We present in vivo results of an innovative device characterized by an intraventricular segment designed to enable artificial chordae implantation and simplify leaflets and subvalvular apparatus correction. Methods: Eight sheep were employed. The first 4 underwent solely device implantation. In the last 4, primary chordae of the anterior leaflet (A2) were torn to induce severe mitral regurgitation. The severed chordae were replaced by 2 pairs of 5-0 Gore-Tex artificial chordae previously measured and anchored to the device bridge. Ease of device and chordae implantation were evaluated, and postprocedural valve competence was verified by postoperative echocardiogram. Results: The procedure was completed in all 8 sheep. In the 4 sheep with induced severe mitral regurgitation, repair could be achieved by means of artificial chordae implantation. Length of the 2 chordae implanted was 21.6 ± 2 mm and 22 ± 3 mm, respectively. The time required to suture the artificial chordae was 2.5 ± 1.2 min. Postoperative echocardiograms showed normal left ventricular ejection fraction and free motion of the mitral leaflets. Mitral regurgitation was absent in 5 cases and trivial in 3. The transvalvular peak pressure gradient was 9.5 ± 6 mm Hg, and mean gradient was 3.7 ± 4 mm Hg. Postprocedural evaluation of the heart and mitral valve showed no damage to the left ventricle wall, valve leaflets, chordae, and papillary muscles. Conclusions: In vivo tests confirm safety of the device, ease of chordal length estimation prior to implantation, short operative time, and no negative impact of the device on mitral leaflet motion, function, and structure.