Padala Muralidhar, Powell Scott N, Croft Laura R, Thourani Vinod H, Yoganathan Ajit P, Adams David H
Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0535, USA.
J Thorac Cardiovasc Surg. 2009 Aug;138(2):309-15. doi: 10.1016/j.jtcvs.2009.01.031.
Leaflet prolapse resulting from acute chordal rupture is one presentation of fibroelastic deficiency that is associated with minimal leaflet changes in the prolapsing segment. Minimizing resection and preserving leaflet tissue may be an optimal surgical strategy. We examined the importance of the leaflet preservation concept by comparing resective and nonresective surgical procedures in practice today.
Eight porcine mitral valves were evaluated in an in vitro heart simulator before surgical manipulation. Mitral regurgitation was created in these valves by transecting the posterior marginal chordae resulting in severe P2 prolapse. After confirmation of mitral regurgiation via regurgitant flow measurement (mL/beat), regurgitation was corrected by three repairs: neochordoplasty with polytetrafluoroethylene sutures (Gore-Tex; W. L. Gore & Associates, Inc, Flagstaff, Ariz), triangular resection, and quadrangular resection with annular compression. Postrepair valve hemodynamics were quantified under pulsatile conditions of 120 mm Hg peak transmitral pressure and 5 L/min cardiac output at 70 beats/min. Furthermore, hemodynamic, geometric, and echocardiographic indices were measured.
Transecting the marginal chordae resulted in severe P2 prolapse and significant mitral regurgiation (19.3 +/- 4.3 mL/beat). Regurgitant volume was significantly reduced after any of the three surgical approaches (quadrangular, 4.38 +/- 1.6 mL/beat; triangular, 2.56 +/- 1.0 mL/beat; neochordal, 2.86 +/- 1.24 mL/beat). In comparison with the baseline normal valves, leaflet coaptation length and posterior leaflet mobility were significantly reduced in the quadrangular resection group, whereas they were partially restored in the triangular resection and fully preserved in the neochordoplasty group.
Although the three repair procedures are hemodynamically comparable, valve function and leaflet kinematics were significantly better after a nonresection or limited resective correction of leaflet prolapse in this experimental model of acute chordal rupture with otherwise normal leaflet geometry.
急性腱索断裂导致的瓣叶脱垂是纤维弹性组织缺乏的一种表现，与之相关的是脱垂节段的瓣叶变化极小。尽量减少切除并保留瓣叶组织可能是最佳的手术策略。我们通过比较当今实践中的切除性和非切除性手术方法，研究了瓣叶保留概念的重要性。
在体外心脏模拟器中对8个猪二尖瓣进行手术操作前评估。通过横断后缘腱索在这些瓣膜中造成二尖瓣反流，导致严重的P2瓣叶脱垂。通过反流流量测量（毫升/搏）确认二尖瓣反流后，通过三种修复方法纠正反流：用聚四氟乙烯缝线（戈尔泰克斯；W.L.戈尔联合公司，亚利桑那州弗拉格斯塔夫）进行新腱索成形术、三角形切除和带瓣环压缩的四边形切除。在120毫米汞柱的峰值跨二尖瓣压力和70次/分钟的心率下，在5升/分钟的心输出量的搏动条件下对修复后瓣膜的血流动力学进行量化。此外，还测量了血流动力学、几何和超声心动图指标。
横断边缘腱索导致严重的P2瓣叶脱垂和显著的二尖瓣反流（19.3±4.3毫升/搏）。三种手术方法中的任何一种（四边形，4.38±1.6毫升/搏；三角形，2.56±1.0毫升/搏；新腱索，2.86±1.24毫升/搏）后反流体积均显著减少。与基线正常瓣膜相比，四边形切除组的瓣叶对合长度和后叶活动度显著降低，而在三角形切除组中部分恢复，在新腱索成形术组中完全保留。
在这个瓣叶几何形状正常的急性腱索断裂实验模型中，尽管三种修复手术在血流动力学上相当，但在对瓣叶脱垂进行非切除或有限切除矫正后，瓣膜功能和瓣叶运动学明显更好。
