Preclinical Animal Study of a Dual-Set Artificial Chordae Mitral Valve Repair System in a Porcine Model

Background Implantation of expanded polytetrafluoroethylene (ePTFE) artificial chordae is an established approach for mitral valve repair, but current transapical systems are typically limited to single-thread implantation per delivery and remain procedurally complex. This study evaluated the feasibility, safety, and mid-term efficacy of the HaloChord® system, which delivers up to two sets (four threads) of ePTFE chordae per sequence, in a porcine model of acute mitral regurgitation (MR). Methods Five adult Large White pigs (60–80 kg) underwent transapical induction of acute moderate to moderately severe MR via surgical blunt disconnection of the primary chordae tendineae attached to the P2 segment. Under beating-heart transesophageal echocardiographic (TEE) guidance, one or two suturing devices per animal were deployed with the HaloChord® system and anchored at the left ventricular apex. Animals followed a staged terminal-endpoint design (n = 1 at 30 days, n = 1 at 90 days, n = 3 at 180 days). Evaluations included serial echocardiography, clinical pathology, gross examination, and histopathological scoring per GB/T 16886.6–2022 Annex E. Results Implantation succeeded in all 5 animals; two received one suturing device (4 equivalent chordae) and three received two suturing devices (8 equivalent chordae). Suturing-device operation time was 10.5 ± 5.10 min per device; fixation-device operation time was 5.2 ± 6.14 min per cycle, with the wide fixation-time variability reflecting iterative echocardiographic length titration. MR grade was reduced from 2 + to 3 + post-modeling to ≤ 1 + immediately post-procedure and remained stable through each terminal endpoint. Vena contracta width decreased substantially and remained stable at follow-up. Gross examination confirmed stable anchoring with no detachment, rupture, or thrombus. Histopathological scoring showed a more pronounced tissue response at 30 days that moderated to predominantly moderate scores at 90 and 180 days, driven primarily by fibrosis and neovascularization rather than active inflammation. Conclusions In this porcine acute MR model, the HaloChord® system demonstrated procedural feasibility on the beating heart, effective acute MR reduction, and acceptable mid-term device stability and biocompatibility. The dual-set delivery design simplifies transapical chordal implantation, providing a foundation for clinical evaluation.