Simplifying transcatheter mitral annuloplasty: the L-Clip challenge
Functional mitral regurgitation (FMR) is closely linked to mitral annular dilatation. While surgical annuloplasty remains the standard of care, current transcatheter alternatives, such as the Cardioband system, suffer from major procedural complexity requiring the implantation of numerous anchors and exposing patients to risks of coronary artery injury. To address these limitations, the L-Clip system offers a simplified approach based on a dual-arm clip technology combined with a controlled-penetration helical anchor.
The objective of this preclinical study conducted on 18 porcine models was to evaluate the technical feasibility, safety, and hemodynamic efficacy of this new device. The authors tested the hypothesis that a simplified two-clip procedure would achieve a significant reduction in mitral annulus dimensions with a superior safety profile compared to existing technologies. The study aimed to demonstrate total procedural success as well as stability of morphological results over a follow-up period of up to 90 days, while eliminating classic complications related to complex intracardiac navigation.
Methodology of the preclinical evaluation of the L-Clip system
This in vivo study evaluated the feasibility and safety of the L-Clip device in a porcine model. The sample included 18 pigs (median weight of 98.7 kg, 66.7% male), divided into three cohorts of 6 animals according to the follow-up period: acute, 28 days, and 90 days.
The experimental protocol followed these steps:
- Access and guidance: Procedure under general anesthesia with heparin administration (ACT maintained between 250 and 500 s). The mitral approach was established by transseptal puncture via the right femoral vein, under dual fluoroscopic and echocardiographic guidance (3D and X-plane).
- Implantation: The system uses a 23F outer sheath and a 17F inner sheath. Two 10 mm clips were deployed per subject, specifically targeting the P1 and P3 segments of the posterior mitral annulus. Each clip has an anchor with a corkscrew mechanism limited to 4 mm in depth.
- Vascular control: Coronary angiography was systematically performed before clip detachment to exclude any induced stenosis.
Morphological efficacy criteria (annular area, anteroposterior diameter, and intercommissural distance) were measured by echocardiography at baseline, immediately post-procedure, and at 28 and 90 days. Statistical analysis used the Wilcoxon test (significance threshold p < 0.05). A terminal histopathological evaluation examined the endothelialization and tissue integration of the devices.
Results: Technical success and significant annular remodeling
The study conducted on 18 porcine models demonstrated a 100% procedural success rate, with the successful implantation of 36 devices (two clips per subject). The median procedure time was 28.4 minutes [22.7-34.1] for the first clip and 39.7 minutes [31.2-48.2] for the second.
Immediate morphological efficiency
Immediate post-procedural echocardiography revealed a significant and systematic reduction in mitral annular dimensions (all P < 0.001). These parameters remained stable during the 90-day follow-up (P > 0.05 compared to immediate post-operative measurements).
| Parameter (Diastole) | Baseline (median [IQR]) | Post-procedure (median [IQR]) | Reduction (%) |
|---|---|---|---|
| Annular area (cm²) | 13.4 [11.2-15.6] | 9.9 [7.5-12.3] | -26 % |
| A-P Diameter (cm) | 3.6 [3.2-4.0] | 2.5 [2.0-3.0] | -31 % |
| Intercommissural distance (cm) | 4.1 [3.8-4.4] | 3,4 [3,1-3,7] | -17 % |
Safety and anatomopathological analysis
The preclinical safety profile proved to be excellent, with no cases of mortality, device migration, coronary stenosis, or thrombotic events. No new mitral regurgitation was induced by the procedure.
- Tissue integration: At 90 days, histological analyses confirmed complete endothelialization of the clips and robust integration into the tissues without annular lesion.
- Systemic safety: Macroscopic examination of vital organs (brain, liver, kidneys, lungs) revealed no abnormalities or signs of embolization related to the material.
- Anchorage stability: The screw fixation mechanism (depth ≤ 4 mm) allowed for stable maintenance of the clips throughout the study.
Towards a simplification of percutaneous mitral annuloplasty
The results of this preclinical study mark a significant milestone in the development of transcatheter therapies. By achieving a robust reduction in mitral annulus dimensions — including area and anteroposterior diameter — via only two anchoring points, the L-Clip system demonstrates that a simplified approach is not only feasible but also stable at 90 days. Clinically, this architectural restructuring occurs without inducing a pathological transvalvular gradient or de novo regurgitation, a crucial balance for the future management of functional mitral regurgitation.
The main advantage lies in procedural ergonomics. Unlike current, more complex devices, the targeted deployment of two clips reduces technical complexity and the associated risks of coronary lesions. The speed of execution is notable: while the first clip shows a median implantation time of 28.4 minutes, the second stabilizes at 39.7 minutes, durations that promote fluid integration in the catheterization laboratory.
However, caution is required regarding the generalization of these data. The study is based on a limited sample of 18 healthy porcine models, which does not fully reflect the tissue complexity of a dilated and pathological ring. Furthermore, while complete endothelialization at 90 days is encouraging for medium-term safety, the chronic durability of the mechanical anchoring under human physiological stresses remains to be documented.
In the long term, the L-Clip could redefine the standards of percutaneous annuloplasty, either as a standalone treatment or as a therapeutic foundation prior to transcatheter edge-to-edge repair (TEER) to optimize outcomes for complex residual leaks.
L-Clip: An effective and secure annular reduction
This preclinical study confirms a 100% technical success rate, with an immediate and stable 90-day reduction of 26% in the annular area (13.4 to 9.9 cm²), 31% in the anteroposterior diameter (3.6 to 2.5 cm), and 17% in the intercommissural distance (p < 0.001). No major adverse events, such as coronary stenosis or device migration, were observed.
In concrete terms, for the practitioner:
- Simplification of the procedure: Unlike conventional multi-anchor systems, the two-clip approach drastically reduces technical complexity and procedure time (average < 30 min per clip).
- Optimised anchoring safety: The screwing mechanism limited to a 4 mm depth secures the implantation by preventing cardiac perforations and collateral vascular damage.
- Therapeutic synergy: The marked efficacy on the anteroposterior diameter suggests a foundational role for initial annular remodeling, potentially prior to TEER treatment to optimize the final outcome.
Technical lexicon of the L-Clip study
L-Clip: Next-generation transcatheter mitral annuloplasty device, consisting of a double-arm clip with gripping teeth and an anchor for mitral annulus remodeling.
Corkscrew mechanism: Controlled-depth anchoring system (limited to ≤4 mm) allowing the device to be fixed into the posterior annular tissue without risk of cardiac perforation.
Steerable delivery sheaths: Coaxial catheter system comprising an outer sheath (23F, ±90°) and an inner sheath (17F, 0-270°), designed to precisely align the clip parallel to the mitral valve plane.
Anteroposterior (AP) diameter: Transverse dimension of the mitral annulus measured by echocardiography; its significant reduction is a key marker of annuloplasty effectiveness in functional mitral regurgitation.
Intercommissural distance: Measurement of the longitudinal axis of the ring between the two valvular commissures, used to evaluate the impact of the device on the overall geometry of the valve.
Endothelialization: Biological process of clip coverage by endothelial cells, observed at 90 days, ensuring stable tissue integration and the absence of thrombus.
TEER (Transcatheter Edge-to-Edge Repair): Percutaneous mitral repair technique (leaflet clipping type) mentioned as a complementary approach that can be combined with L-Clip annuloplasty.
Source
- Original title: Novel Direct Transcatheter Mitral Annuloplasty System
- Authors: Wanjiao Chen, Yuliang Long, Wei Li, Xiaochun Zhang, Lei Zhang, Daxin Zhou, Wenzhi Pan, Junbo Ge
- Publication: JACC Asia - 2026-08-01
- DOI: https://doi.org/10.1016/j.jacasi.2026.04.045
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