Remodeling potential of the mitral valve following surgical repair

描述（由申请人提供）：在强调瓣膜置换术20年后，心脏外科医生逐渐转向二尖瓣修复术。二尖瓣修复术，而不是置换术，保持了更好的心室力学和更少的并发症，如心内膜炎，血栓栓塞和抗凝剂相关出血。不幸的是，最近的长期研究使用更严格的失败定义，发现修复耐久性的结果不太乐观;对这种积极的手术实践提出质疑，并建议 维修技术虽然成熟，但仍有待改进。在大多数情况下，失效是瓣叶、腱索或瓣环缝合线断裂的结果。这些失效模式表明过度的组织应力和由此产生的应变诱导的组织损伤是一个病因。因此，人们越来越关注为IMR患者开发更稳健的修复策略。有前景的概念包括瓣叶增大以恢复瓣叶活动性，以及鞍形瓣环成形术以恢复正常瓣环形状。如果设计正确，瓣叶加固技术可以通过促进瓣叶曲率和接合来缓解腱索-瓣叶栓系并降低瓣叶应力。瓣叶扩张还允许放置更大的瓣成形环，这将减少瓣环-瓣成形环分离力。因此，我们假设，与单独的尺寸过小的扁平瓣环成形术相比，恢复正常瓣环几何结构（尺寸和形状）并恢复移动的瓣叶组织的IMR修复技术将导致瓣环和腱索力分布降低。这反过来将导致恢复稳态正常组织应力水平和MVIC生物合成反应，最终导致改善的修复耐久性。

DESCRIPTION (provided by applicant): After two decades of emphasis on valve replacement, cardiac surgeons have been gradually turning to mitral valve repair. MV repair, rather than replacement, maintains better ventricular mechanics and fewer complications, such as endocarditis, thromboembolism, and anticoagulant-related hemorrhage. Unfortunately, recent long term studies using more rigorous definitions of failure have identified less optimistic result for repair durability; bringing into question such aggressive surgical practice and suggesting that repair techniques though mature can be improved upon. In most cases, failures were a result of disruption at the leaflet, chordal, or annular suture lines. These failure modes suggest excessive tissue stress and the resulting strain induced tissue damage as an etiologic factor. Thus, there has been growing interest in developing more robust repair strategies for patients with IMR. Promising concepts include leaflet augmentation to restore leaflet mobility, and saddle shaped annuloplasty to restore normal annular shape. If designed correctly, leaflet augmentation techniques can alleviate chordal-leaflet tethering and reduce leaflet stress by promoting leaflet curvature and coaptation. Leaflet augmentation will also allow the placement of larger annuloplasty rings that should reduce annular-annuloplasty ring separation forces. We thus hypothesize that IMR repair techniques that reinstate normal annular geometry (size and shape) and restore mobile leaflet tissue will result in reduced annular and chordal force distribution compared with undersized flat annuloplasty alone. This in turn will lead to restoration of homeostatic normal tissue stress levels and MVIC biosynthetic responses, ultimately leading to improved repair durability.