Usability, performance and safety of a new device for degenerative mitral regurgitation: in vivo chronic evaluation

OBJECTIVES: This study aimed to evaluate the usability, performance and safety of an innovative mitral valve device in the chronic setting characterized by an intraventricular bridge, which enables artificial chordae anchoring and/or direct posterior leaflet fixation. METHODS: Ten female sheep were employed and underwent device implantation. Any interference of the device with leaflet motion, ease of device use, correct chordae length estimation and implantation were evaluated. Post-procedural valve competence and device performance were verified by periodic postoperative echocardiograms and laboratory examinations. Following euthanasia, gross anatomy and histology evaluation of the hearts and valves were performed to detect tissue abnormalities and inflammation reaction related to the device. RESULTS: The procedure was successfully completed in all 10 sheep. Lengths of the 2 chordae implanted were 23 (21.5-24) mm and 23 (22.5-24) mm. The time required to suture both pairs of the artificial chordae was 2.7 +/- 0.7 min. At the 3-month follow-up, left ventricular function was normal. The transvalvular peak pressure gradient was 9 (7.5-10) and the mean gradient was 4 (3.5-4) mmHg. Upon necropsy and histological evaluation, no damage to left ventricle wall, valve leaflets, chordae and papillary muscles and absence of thrombus formation and inflammatory reaction were observed. Radiological images showed neither fracture of the device nor calcifications. Laboratory tests showed no signs of haemolysis. CONCLUSIONS: In vivo late tests confirmed the ease of correct chordal length estimation prior to implantation, short operative time and usability in flailed anterior leaflet repair. The absence of negative impact of the device on mitral leaflets motion, function and structure and successful repair might suggest that the device would be useful in complex degenerative mitral disease.