Zhu Yuanjia, Yajima Shin, Wilkerson Robert J, Park Matthew H, Kim Joo Young, Pandya Pearly K, Woo Y Joseph
Department of Cardiothoracic Surgery, Stanford University, Stanford, California.
Department of Bioengineering, Stanford University, Stanford, California.
Ann Thorac Surg Short Rep. 2023 Feb 21;1(2):302-306. doi: 10.1016/j.atssr.2023.02.006. eCollection 2023 Jun.
The objective of this study was to biomechanically evaluate anterior pericardial patch augmentation repair and the modified technique using neochord implantation in an ex vivo rheumatic mitral valve (RMV) model.
Thermal treatment to the leaflets and chordae and commissure fusion were performed on 4 healthy porcine mitral valves to generate the ex vivo RMV model. Repair was performed by conducting commissural release and anterior pericardial patch augmentation, with or without implantation of 2 neochordae. Hemodynamic, echocardiography, native chordal forces, and high-speed videography data were collected.
Compared with baseline, the RMV model successfully generated mitral regurgitation with a regurgitant fraction (RF) of 20.3% ± 9.4% ( = .03) and decreased coaptation height of 0.5 ± 0.3 cm ( = .004). Compared with the RMV model, patch augmentation repair improved regurgitation with an RF of 3.3% ± 1.7% ( = .05) and coaptation height of 1.4 ± 0.3 cm ( = .003); the rates of change of primary (0.1 ± 0.4 N/s vs 2.0 ± 1. 2 N/s; = .05) and secondary (3.1 ± 1.7 N/s vs 5.3 ± 0.9 N/s; = .002) chordal forces were also decreased. The modified technique enhanced valve hemodynamics by improving RF (3.4% ± 2.2%; = .12) and coaptation height (1.8 ± 0.3 cm; = .09) to levels similar to those from baseline. Compared with patch augmentation repair, the rates of change of force of secondary chordae were further decreased (2.1 ± 1.3 N/s; = .05).
Anterior pericardial patch augmentation was effective in repairing RMV by re-establishing coaptation while reducing mean gradient. The modified technique further improved valve hemodynamics and native chordal forces. This study provides biomechanical evidence in favor of anterior pericardial patch augmentation repair and may direct further repair modifications to improve clinical outcomes.
本研究的目的是在体外风湿性二尖瓣（RMV）模型中对心包前片扩大修补术及使用新腱索植入的改良技术进行生物力学评估。
对4个健康猪二尖瓣进行瓣叶、腱索热处理及瓣叶融合，以建立体外RMV模型。通过进行瓣叶交界松解和心包前片扩大修补术进行修复，有或没有植入2根新腱索。收集血流动力学、超声心动图、天然腱索力和高速摄像数据。
与基线相比，RMV模型成功产生二尖瓣反流，反流分数（RF）为20.3%±9.4%（P = .03），瓣叶对合高度降低0.5±0.3 cm（P = .004）。与RMV模型相比，心包片扩大修补术改善了反流，RF为3.3%±1.7%（P = .05），瓣叶对合高度为1.4±0.3 cm（P = .003）；主腱索（0.1±0.4 N/s对2.0±1.2 N/s；P = .05）和次腱索（3.1±1.7 N/s对5.3±0.9 N/s；P = .002）力的变化率也降低。改良技术通过改善RF（3.4%±2.2%；P = .12）和瓣叶对合高度（1.8±0.3 cm；P = .09）将瓣膜血流动力学提高到与基线相似的水平。与心包片扩大修补术相比，次腱索力的变化率进一步降低（2.1±1.3 N/s；P = .05）。
心包前片扩大修补术通过重新建立瓣叶对合同时降低平均压差，有效修复RMV。改良技术进一步改善了瓣膜血流动力学和天然腱索力。本研究提供了支持心包前片扩大修补术的生物力学证据，并可能指导进一步的修复改良以改善临床结果。
