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Objectives: Transcatheter mitral valved stent implantation provides an off-pump treatment option for mitral valve regurgitation, especially for secondary mitral valve regurgitation. The aim of this study was to evaluate novel fixation strategies: direct fixation (SUPRA) and subvalvular fixation (sub-VALV) to successfully implement alternative fixation methods at the mitral annulus and to reduce radial stent and apical tether forces., Methods: Specific concepts were developed for the supra-annular hook-shaped fixation (SUPRA) and the subvalvular fixation (sub-VALV). These prototypes were compared with the sole apical tether fixation (AP) methods. Thirty-three pigs underwent mitral valved stent implantation accompanied by standardized transoesophageal echocardiographic and haemodynamic evaluation of heart function and the stent performance 1 h after implantation. Additionally, animals were followed up for 3 months., Results: Secure deployment and correct positioning with low transvalvular gradients were achieved in all cases with mitral valved stent implantation. Nevertheless, 2 pigs died due to rhythm disturbances during dissection and pre-transcatheter mitral valve implantation. Paravalvular leakages were trace or less in prototypes with supra-annular fixation and sole apical fixation. In contrast, moderate paravalvular leakages were observed in the sub-VALV group (P < 0.001). In addition, the effect of a specific stent design on heart function was demonstrated: an increased rate of ischaemia and arrhythmia (P = 0.037) and a small left ventricular ejection fraction reduction (P < 0.05) were observed in the group with subvalvular fixation. In all but 1 case, gross evaluation demonstrated a good ingrowth of the valved stents of between 36% and 100% tissue coverage after a follow-up of 1 month or longer., Conclusions: The low degree of paravalvular leakages in the supra-annular and apical fixation groups and the normal longitudinal function highlight the good alignment of these new mitral valved stent designs within the native anatomy. The novel, hook-shaped, supra-annular fixation elements were well tolerated in the hearts resulting in excellent health of the animals at long-term follow-up times of up to 3 months.

Background/objectives: This study presents the recent results of transapical implantation of a new design of a mitral valved stent with up to three months follow-up., Methods: A self-expanding re-designed mitral valved stent was implanted via transapical approach into the beating heart of eight pigs. Echocardiographic- and hemodynamic parameters were assessed before (n=8), at 1h (n=8), at one month (n=6), at two months (n=2), and at three months (n=1) after implantation and a cardiac CT was conducted., Results: The stent was successfully deployed in all animals. Two animals died within the first month due to incorrect fixation force. Echocardiographic evaluation showed low gradients (3.9 ± 1.4 mm Hg and 1.9 ± 0.8 mm Hg across the valved stent and aortic valve) and a normal mitral annular plane systolic excursion (1.1 ± 0.2 cm) after one month. No paravalvular leakages (PVL) were detected after 1h. The pulmonary artery pressure did not increase after valved stent implantation (p ≥ 0.106). The pulmonary capillary wedge pressure (PCWP) slightly increased to 16 ± 3 mm Hg after one month (p=0.033). The left ventricular end-diastolic pressure was mildly elevated (15.8 ± 8.6 mm Hg) after one month., Conclusions: Secure deployment and correct position of the valved stents were reproducibly achieved in the off-pump implantation procedure. No paravalvular leakages after 1h as well as low gradients, few stent fractures and a normal longitudinal function after one month were achieved with this newly developed and well-aligned prototype. However, a number of challenges have been identified during this study and potential for improvement has been identified., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)