Percutaneous approaches to mitral valve (MV) repair have received a great deal of interest, as they avoid open-chest surgery and are often the only option for patients with significant co-morbidities [1]. One technique currently in development is a combined radiofrequency (RF) ablation and cryo-anchoring catheter, and we recently demonstrated that reduction of MV leaflet surface area due to RF ablation is feasible in the proximity of cryo-anchoring [2]. This reduction of enlarged, diseased MV leaflets is designed to improve leaflet coaptation and reduce mitral regurgitation. However, myocardial infarcts treated with RF ablation re-dilated in 20–30 days without the application of a retaining patch [3]. Additionally, joint capsular tissues treated with RF ablation reduced in stiffness and ultimate strength over the first six weeks before regaining strength and stiffness [4]. Re-dilation of MV tissues treated with combined RF ablation and cryo-anchoring would reverse the effects of the treatment strategy. Therefore, we hypothesized that excised porcine MV leaflets treated with combined RF ablation and cryo-anchoring would undergo little to no re-dilation over four weeks. Biaxial mechanical testing at 0 and 4 week time points and picrosirius red (PSR) staining was used to assess the degree of re-dilation and collagen morphological changes following 4 week bioreactor treatment of cyclic uniaxial tension.

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