Key result
In an ex vivo model, moderate residual mitral regurgitation after neochord repair significantly increased peak forces on anterior primary (0.43 vs 0.19 N; P=0.011) and secondary chordae.
Why the study?
To biomechanically evaluate the force profiles on anterior primary and secondary chordae after neochord repair for anterior valve prolapse with varying degrees of residual mitral regurgitation.
p-value: p=0.011
Moderate residual mitral regurgitation after neochord repair significantly increases chordal forces, providing biomechanical evidence to support achieving minimal residual regurgitation during anterior mitral valve prolapse repair.
Ex vivo chordal force data after neochord repair with residual MR should not alter practice; leaves open need for in vivo validation.
Objective This study aimed to biomechanically evaluate the force profiles on the anterior primary and secondary chordae after neochord repair for anterior valve prolapse with varied degrees of residual mitral regurgitation using an ex vivo heart simulator. Methods The experiment used 8 healthy porcine mitral valves. Chordal forces were measured using fiber Bragg grating sensors on primary and secondary chordae from A2 segments. The anterior valve prolapse model was generated by excising 2 primary chordae at the A2 segment. Neochord repair was performed with 2 pairs of neochords. Varying neochord lengths simulated postrepair residual mitral regurgitation with regurgitant fraction at >30% (moderate), 10% to 30% (mild), and <10% (perfect repair). Results Regurgitant fractions of baseline, moderate, mild, and perfect repair were 4.7% ± 0.8%, 35.8% ± 2.1%, 19.8% ± 2.0%, and 6.0% ± 0.7%, respectively ( P < .001). Moderate had a greater peak force of the anterior primary chordae (0.43 ± 0.06 N) than those of baseline (0.19 ± 0.04 N; P = .011), mild (0.23 ± 0.05 N; P = .041), and perfect repair (0.21 ± 0.03 N; P = .006). In addition, moderate had a greater peak force of the anterior secondary chordae (1.67 ± 0.17 N) than those of baseline (0.64 ± 0.13 N; P = .003), mild (0.84 ± 0.24 N; P = .019), and perfect repair (0.68 ± 0.14 N; P = .001). No significant differences in peak and average forces on both primary and secondary anterior chordae were observed between the baseline and perfect repair as well as the mild and perfect repair. Conclusions Moderate residual mitral regurgitation after neochord repair was associated with increased anterior primary and secondary chordae forces in our ex vivo anterior valve prolapse model. This difference in chordal force profile may influence long-term repair durability, providing biomechanical evidence in support of obtaining minimal regurgitation when repairing mitral anterior valve prolapse.
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Yajima et al. (2023) studied Anterior mitral valve prolapse (n=8). Neochord repair with varying degrees of residual mitral regurgitation vs. Baseline and perfect repair was evaluated on Peak force of the anterior primary and secondary chordae (p=0.011). In an ex vivo model, moderate residual mitral regurgitation after neochord repair significantly increased peak forces on anterior primary (0.43 vs 0.19 N; P=0.011) and secondary chordae.
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