In vivo quantification of the apical fixation forces of different mitral valved stent designs in the beating heart

The aim of this study was the quantification of the apical fixation forces of mitral valved stents for the first time. A test set-up was developed to measure the forces acting on the apical fixation of mitral valved stents. Twenty pigs received a self-expanding valved stent in the mitral position via a transapical approach in an off-pump procedure. Following stent deployment in the beating heart, the apical fixation forces were recorded following a standardized protocol and normalized. The apical fixation force of two different valved stent designs (AP: sole apical fixation, n = 10; SA: additional sub-annular fixation, n = 10) was compared to quantify the impact of the design change. Force measurement was successfully conducted in 18 of 20 animals (design AP: n = 10; design SA: n = 8). Evaluation showed higher mean forces and amplitude in the group with sole apical fixation (p = 0.046; Table 1). The impact of the additional sub-annular fixation was shown by a significant reduction of the force acting upon the apex of the heart. Quantification of these in vivo forces provides important information about the impact of different stent designs and might provide an objective parameter for stent performance evaluation in clinical application.