Ex Vivo Model of Functional Mitral Regurgitation Using Deer Hearts

Figures

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  Graphical abstract figure legend: Deer heart mitral valve fiberscopic and echocardiographic images in peak systole at baseline and after inducing the pathological conditions representing functional mitral regurgitation. In the pathological conditions lack of coaptation between the leaflets, enlargement of the antero-posterior distance (red dashed line) and the left ventricular diameter (orange dashed line) were observed.

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  Fig. 1. The scheme of the experimental setup used to perform dilation protocol (A) and test in pulsatile flow conditions (B). The switch between two configurations was by closing the circuit with clamps (red “x”). a, heart sample; b, pulsatile flow pump; c, impedance simulator; d, preload reservoir; e, continuous flow pump

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  Fig. 2. The schematic demonstration of the application of the constraining bands (black curves) and their pulling (represented by red arrows) in order to obtain ischemic functional mitral regurgitation (iFMR), atrial functional mitral regurgitation (aFMR), and physiological models. MA – mitral annulus level, PM – papillary muscles level

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  Fig. 3. The navigation and analysis of the volumetric echocardiographic data. Schematic images of the orthogonal views in which the geometrical measurements were taken. a short axis view with the representation of aortic valve and mitral valve annulus (the dashed line indicate the other two views). b antero-posterior long axis view (like TEE mid esophageal long axis view). c commissural long axis view. AV = aortic valve, MV = mitral valve, AL = anterior leaflet, PL = posterior leaflet, LA = left atrium, LV = left ventricle, A-P = antero-posterior distance, M-L = medio-lateral distance, TH = tenting height, CL = coaptation length, LVd = left ventricular diameter

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  Fig. 4. Dilation protocol. Mitral valve views from fiberscope (atrial view, left) and 2D echocardiography (TEE mid esophageal long axis like view, right) before (upper row) and after (lower row) application of the dilation protocol. Red dash line, antero-posterior distance; blue dashed line, coaptation length; orange dashed line, left ventricular diameter. AL = anterior leaflet, PL = posterior leaflet, MV = mitral valve, LA = left atrium, LV = left ventricle

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  Fig. 5. Characterization of the model. Exemplary mitral valve views from fiberscope (atrial view, left) and 2D echocardiography (3 chambers like view, right) in ischemic functional mitral regurgitation (iFMR), atrial functional mitral regurgitation (aFMR), and physiological model

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  Fig. 6. Feasibility of the application of mitral valve treatments (upper row, edge-to-edge technique; lower row, leaflet augmentation technique) in the proposed pathological model. Exemplary mitral valve views from the fiberscope in atrial view during peak systole (left) and diastole (right)

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  Fig. 7. Anatomical assessment of mitral valve of deer hearts. ha = anterior leaflet height, hp = posterior leaflet height, La = anterior leaflet length, Lp = posterior leaflet length, Aa = anterior leaflet area, Ap = posterior leaflet area, Lcl = length of lateral papillary muscle tendinous chordae, Lcm = length of medial papillary muscle tendinous chordae