Key result
Ex vivo mitral valve repair reduces regurgitant fraction by an absolute ~19% in functional MR.
Why the study?
Preclinical studies are needed to assess the efficacy of transcatheter mitral valve repair technologies in mitigating mitral regurgitation, but ex vivo mitral regurgitation models are not established.
These novel, controllable ex vivo models of functional and degenerative mitral regurgitation can reliably produce sufficient regurgitation meeting interventional indications, offering a valuable platform for the preclinical evaluation of emerging transcatheter mitral valve repair devices.
Establishes reproducible porcine models for mitral repair testing; leaves open clinical translation of ex vivo techniques.
OBJECTIVES: Transcatheter mitral valve repair is an emerging alternative to the surgical repair. This technology requires preclinical studies to assess efficacy in mitigating mitral regurgitation (MR). However, ex vivo MR models are not established. We developed 2 novel repairable models, functional and degenerative, which can quantitatively assess regurgitation and effect of intervention. METHODS: We used porcine mitral valves and a pulsatile flow circulation system. In the functional MR model, the annulus was immersed in 0.1% collagenase solution and dilated using 3D-printed dilators. To control the regurgitation grade, the sizes of the dilator and silicone sheet in which the valve was sutured to were adjusted. Chordae of P2 were severed in the degenerative model, and the number of severed chordae was adjusted to control the regurgitation grade. Models were repaired using the edge-to-edge or artificial chordae technique. RESULTS: The mean regurgitant fraction of the moderate-severe functional and degenerative models were 47.9% [standard deviation (SD): 2.2%] and 58.5% (SD: 8.0%), which were significantly reduced to 28.7% (SD: 4.4%) (P < 0.001) and 26.0% (SD: 4.4%) (P < 0.001) after the valve repair procedures. Severe functional model had a mean regurgitant fraction of 59.4% (SD: 6.0%). CONCLUSIONS: Both functional and degenerative models could produce sufficient MR levels that meet the interventional indication criteria. The repairable models are valuable in evaluating the efficacy of valve repair procedures and devices. The ability to control the amount of regurgitation enhances the versatility and reliability of these models. These reproducible models could expedite the development of novel devices.
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Morimura et al. (2023) studied Mitral Regurgitation (Ex Vivo Porcine Model) (n=25). Mitral valve repair (edge-to-edge or artificial chordae) vs. Pre-repair state (baseline regurgitation) was evaluated on Mean regurgitant fraction (moderate-severe functional model) (p=<0.001). Ex vivo mitral valve repair significantly reduced the mean regurgitant fraction from 47.9% to 28.7% in the functional MR model and from 58.5% to 26.0% in the degenerative MR model.
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