Abstract
BACKGROUND: 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. METHODS: 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. RESULTS: Compared with baseline, the RMV model successfully generated mitral regurgitation with a regurgitant fraction (RF) of 20.3% ± 9.4% (P = .03) and decreased coaptation height of 0.5 ± 0.3 cm (P = .004). Compared with the RMV model, patch augmentation repair improved regurgitation with an RF of 3.3% ± 1.7% (P = .05) and coaptation height of 1.4 ± 0.3 cm (P = .003); the rates of change of primary (0.1 ± 0.4 N/s vs 2.0 ± 1. 2 N/s; P = .05) and secondary (3.1 ± 1.7 N/s vs 5.3 ± 0.9 N/s; P = .002) chordal forces were also decreased. The modified technique enhanced valve hemodynamics by improving RF (3.4% ± 2.2%; P = .12) and coaptation height (1.8 ± 0.3 cm; P = .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; P = .05). CONCLUSIONS: 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.