Application of deer hearts for ex-vivo modelling of mitral valve pathology – preliminary results

Functional mitral regurgitation (FMR) has high prevalence (2.5% in general population), its surgical treatment is considered challenging and the number of inoperable patients will be increasing due to population aging. Transcatheter treatments represent new therapeutic options for high risk patients, however realistic preclinical tests reproducing peculiarities of the pathology are needed to accelerate their development. In this work, applicability of deer hearts for FMR simulation in an ex-vivo setup was evaluated. Mitral valves (MVs) from 15 samples were harvested and their anatomy was preliminary assessed and compared with human and porcine hearts. Further, 5 deer hearts were tested under steady flow conditions and underwent a dilatation protocol to induce the pathology (constant intraventricular pressurization under 150 mmHg for 60 minutes). The evaluation was based on retrograde flow measurement, 3D volumetric echocardiographic images analysis and fiberscopic direct visualization. The dilatation protocol induced incremental increase of retrograde flow through MV throughout the time of the test. The MV geometry at post-dilatation reproduced the principal characteristics associated with FMR observed clinically and featured annulus dilation, MV leaflets malcoaptation and tenting. The FMR model housing deer hearts is promising for future application in realistic preclinical assessment of MV transcatheter therapies.