Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA.
Department of Bioengineering, Stanford University, Stanford, CA, USA.
Eur J Cardiothorac Surg. 2024 Mar 1;65(3). doi: 10.1093/ejcts/ezae008.
Artificial neochordae implantation is commonly used for mitral valve (MV) repair. However, neochordae length estimation can be difficult to perform. The objective was to assess the impact of neochordae length changes on MV haemodynamics and neochordal forces.
Porcine MVs (n = 6) were implanted in an ex vivo left heart simulator. MV prolapse (MVP) was generated by excising at least 2 native primary chordae supporting the P2 segments from each papillary muscle. Two neochordae anchored on each papillary muscle were placed with 1 tied to the native chord length (exact length) and the other tied with variable lengths from 2× to 0.5× of the native length (variable length). Haemodynamics, neochordal forces and echocardiography data were collected.
Neochord implantation repair successfully eliminated mitral regurgitation with repaired regurgitant fractions of approximately 4% regardless of neochord length (P < 0.01). Leaflet coaptation height also significantly improved to a minimum height of 1.3 cm compared with that of MVP (0.9 ± 0.4 cm, P < 0.05). Peak and average forces on exact length neochordae increased as variable length neochordae lengths increased. Peak and average forces on the variable length neochordae increased with shortened lengths. Overall, chordal forces appeared to vary more drastically in variable length neochordae compared with exact length neochordae.
MV regurgitation was eliminated with neochordal repair, regardless of the neochord length. However, chordal forces varied significantly with different neochord lengths, with a preferentially greater impact on the variable length neochord. Further validation studies may be performed before translating to clinical practices.
人工腱索植入术常用于二尖瓣（MV）修复。然而，腱索长度的估计可能难以进行。目的是评估腱索长度变化对 MV 血液动力学和腱索力的影响。
将猪 MV（n=6）植入离体左心模拟器中。通过从每个乳头肌上切除至少 2 个支持 P2 段的原生初级腱索来产生 MV 脱垂（MVP）。将两条腱索分别固定在每个乳头肌上，一条与原生腱索长度（精确长度）相连，另一条与原生长度的 2×至 0.5×之间的可变长度相连（可变长度）。收集血液动力学、腱索力和超声心动图数据。
腱索植入修复成功消除了二尖瓣反流，修复后的反流分数约为 4%，与腱索长度无关（P<0.01）。与 MVP 相比，瓣叶对合高度也显著改善至最小高度 1.3cm（0.9±0.4cm，P<0.05）。精确长度腱索上的峰值和平均力随着可变长度腱索长度的增加而增加。随着缩短长度，可变长度腱索上的峰值和平均力增加。总体而言，与精确长度腱索相比，可变长度腱索上的腱索力似乎变化更为剧烈。
无论腱索长度如何，腱索修复都能消除 MV 反流。然而，腱索力随不同腱索长度显著变化，可变长度腱索的影响更大。在转化为临床实践之前，可能需要进行进一步的验证研究。
