Key result
Neochord implantation eliminates MR to ~4% regurgitant fraction regardless of chordal length.
Why the study?
Neochordae length estimation during mitral valve repair is difficult, and its impact on mitral valve haemodynamics and chordal forces is unclear.
Does neochordae length impact mitral valve haemodynamics and neochordal forces in an ex vivo porcine model of mitral valve prolapse?
Does neochordae length impact mitral valve haemodynamics and neochordal forces in an ex vivo porcine model of mitral valve prolapse?
Absolute Event Rate: 4% vs 4%
p-value: p=<0.01
While neochordae length does not affect the immediate elimination of mitral regurgitation in an ex vivo model, it significantly alters chordal forces, which may have implications for repair durability.
Neochord length variations alter forces despite consistent MR elimination; leaves open optimal length selection in clinical repair.
OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
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Zhu et al. (2024) studied Mitral valve prolapse (n=6). Variable length neochordae (2x to 0.5x native length) vs. Exact length neochordae was evaluated on Repaired regurgitant fraction (p=<0.01). Neochord implantation eliminated mitral regurgitation with regurgitant fractions of approximately 4% regardless of neochord length (P<0.01), though chordal forces varied significantly.