Rabbah Jean-Pierre M, Siefert Andrew W, Bolling Steven F, Yoganathan Ajit P
Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga.
Department of Cardiac Surgery, Cardiovascular Center, University of Michigan Hospitals, Ann Arbor, Mich.
J Thorac Cardiovasc Surg. 2014 Oct;148(4):1688-93. doi: 10.1016/j.jtcvs.2014.04.008. Epub 2014 Apr 13.
Although restrictive mitral annuloplasty (RMA) has been the preferred surgical treatment of functional ischemic mitral regurgitation (FIMR), some patients with severely dilated left ventricles will experience recurrent mitral regurgitation (MR). Consequently, new surgical strategies have been entertained to compensate for severely dilated ventricles by maximizing coaptation and reducing subvalvular tethering. Anterior leaflet augmentation (ALA) with mitral annuloplasty has been theorized to meet these goals. We compared the mechanistic effects of RMA and adjunct ALA in the setting of FIMR.
Mitral valves were mounted in a clinically relevant left heart simulator. The tested conditions included control, FIMR, RMA, and true-size annuloplasty with either a small or large ALA. The A2-P2 leaflet coaptation length, MR, and strut and intermediary chordal forces were quantified. All repairs alleviated the MR. The coaptation length was significantly increased from FIMR to RMA, small ALA, and large ALA (P<.001). Between repairs, a large ALA created the greatest length of coaptation (P<.05). Tethering forces from the posteromedial strut chordae were reduced from the FIMR condition by all repairs (P<.001). Only a large ALA reduced the intermediate chordal tethering from the FIMR condition (P<.05).
A large ALA procedure created the greatest coaptation and reduced chordal tethering. Although all repairs abolished MR acutely, the repairs that create the greatest coaptation might conceivably produce a more robust and lasting repair in the chronic stage. A clinical need still exists to best identify which patients with altered mitral valve geometries would most benefit from an adjunct procedure or RMA alone.
尽管限制性二尖瓣环成形术（RMA）一直是功能性缺血性二尖瓣反流（FIMR）的首选外科治疗方法，但一些左心室严重扩张的患者仍会出现二尖瓣反流复发（MR）。因此，人们提出了新的外科策略，通过最大限度地增加瓣叶对合面积和减少瓣下牵拉来补偿严重扩张的心室。二尖瓣环成形术联合前叶扩大术（ALA）理论上可以实现这些目标。我们比较了RMA和联合ALA在FIMR情况下的机械效应。
将二尖瓣安装在具有临床相关性的左心模拟器中。测试条件包括对照、FIMR、RMA以及采用小尺寸或大尺寸ALA的真实尺寸二尖瓣环成形术。对A2 - P2瓣叶对合长度、MR以及支柱和弦索的中间力进行量化。所有修复均减轻了MR。从FIMR到RMA、小尺寸ALA和大尺寸ALA，瓣叶对合长度显著增加（P <.001）。在各种修复方法之间，大尺寸ALA产生的对合长度最长（P <.05）。所有修复方法均使后内侧支柱腱索的牵拉力量从FIMR状态降低（P <.001）。只有大尺寸ALA降低了FIMR状态下的中间腱索牵拉（P <.05）。
大尺寸ALA手术产生了最大的瓣叶对合面积并减少了腱索牵拉。尽管所有修复方法都能急性消除MR，但在慢性阶段，产生最大瓣叶对合面积的修复方法可能会产生更稳固和持久的修复效果。临床上仍然需要更好地确定哪些二尖瓣几何形状改变的患者最能从联合手术或单独的RMA中获益。
