Tricuspid Annuloplasty: First Clinical Successes of the K-Clip™ System

Innovating in the face of the surgical impasse of tricuspid regurgitation

Severe tricuspid regurgitation (TR) often places the cardiologist in a therapeutic impasse where the prohibitive operative risk deprives the patient of standard surgical treatment. In this context, the emergence of percutaneous technologies (TTVI) offers a less invasive alternative for fragile profiles. This monocentric prospective study evaluates the feasibility and safety of the K-Clip™ system (HuiHe Healthcare), a transcatheter tricuspid annuloplasty device guided by multimodal imaging (echocardiography and fluoroscopy).

The investigation was conducted on 4 patients presenting with massive or torrential symptomatic TR, rejected for conventional surgery with a mean STS score of 6.7 (range 5.6–11.1). The primary objective is to confirm the procedural success of the device — implanted via jugular access to mechanically reduce the valvular orifice — and to evaluate its short-term safety. The researchers are testing the hypothesis that an effective reduction of the annular diameter by the K-Clip™ induces a significant improvement in NYHA functional class, exercise capacity, and quality of life, with tangible benefits measurable as early as the 30-day follow-up.

Methodology of clinical evaluation

This single-center, single-arm prospective study, conducted under a compassionate use protocol, included 4 consecutive patients suffering from symptomatic severe tricuspid regurgitation (TR) (≥ 3+). Inclusion criteria targeted subjects at high surgical risk with a mean STS score of 6.7 (ranging from 5.6 to 11.1), a NYHA functional class ≥ II, a left ventricular ejection fraction greater than 40%, a TAPSE ≥ 13 mm, and a systolic pulmonary artery pressure ≤ 55 mmHg. Patients presenting with tricuspid stenosis, calcifications of the subvalvular apparatus, or an inability to undergo transesophageal echocardiography (TEE) were excluded.

The experimental protocol was structured around three key phases:

• Anatomical assessment: Evaluation of viability via cardiac CT scan, transthoracic and transoesophageal echocardiography to plan the targeting of the ring.
• Device calibration: Selection of the K-Clip™ size based on the tricuspid ring circumference measured by CT during maximum diastolic opening.
• Implantation: Procedure performed under general anesthesia with dual guidance by fluoroscopy and TEE.

Success was defined by the correct placement of at least one device, a reduction in TR of at least one grade, and hospital discharge without reintervention. Echocardiographic measurements and quality of life scores were compared between baseline and 30-day follow-up.

Procedural Success and 30-Day Safety

The K-Clip™ device implantation was performed with a 100% technical success rate. The distribution of implants varied according to the patients' anatomy: two subjects received two clips, while the other two were treated with a single clip. Regarding safety, no major adverse cardiovascular events (MACE) were reported, either during the procedure or at the 30-day follow-up. The study reports no all-cause mortality, myocardial infarction, stroke, or major vascular complications.

Reduction of Tricuspid Regurgitation Parameters

Hemodynamic efficacy resulted in a reduction of at least one grade in tricuspid regurgitation (TR) severity in all patients. Echocardiographic measurements at 30 days show a statistically significant decrease in regurgitation indicators:

Functional Improvement and Quality of Life

Beyond the anatomical gains, the clinical benefits perceived by patients are notable. A significant improvement in the NYHA functional class was observed. Quality of life scores and physical capacities progressed concomitantly:

• KCCQ Score (Kansas City Cardiomyopathy Questionnaire): Increase from 37.58 ± 6.48 to 58.55 ± 5.13 (p < 0.01), reflecting a clear improvement in perceived health status.
• 6-minute walk test (6MWT): The distance covered increased from 239.67 ± 31.64 m to 402.67 ± 41.53 m (p < 0.05), representing an average gain of more than 160 metres in one month.

These preliminary results confirm that the reduction of the tricuspid orifice by annuloplasty plication allows for rapid functional recovery in patients initially considered to be at high surgical risk.

Analysis and clinical perspectives

The results of this pilot study confirm the technical feasibility of percutaneous annuloplasty using the K-Clip™ system in patients presenting with severe tricuspid regurgitation (TR) and a prohibitive surgical risk. The significant improvement in echocardiographic parameters, notably the reduction in effective regurgitant orifice area (EROA) and regurgitation volume, demonstrates the mechanical efficacy of the device in the short term. This valvular correction translates clinically into a notable improvement in functional capacity and quality of life for patients, validated by the increase in walking distance and perceived health scores.

These observations align with preliminary data reported in the literature, corroborating the safety of the device and the absence of major adverse events at 30 days. Precise targeting of the posterior annulus, guided by dual imaging (transesophageal echocardiography and fluoroscopy), allows for effective plication while minimizing the risk of coronary lesions, a critical point for the success of the procedure.

However, the scope of these findings remains limited by the very small cohort size and a follow-up restricted to one month. While the procedural success is encouraging, the long-term durability of TR reduction and the actual impact on right ventricular remodeling require larger prospective studies to confirm the role of the K-Clip™ in the therapeutic arsenal for complex valvular heart diseases.

Summary of results

This pilot study on 4 patients demonstrates a significant reduction in tricuspid regurgitation (TR) using the K-Clip™ system. At 30 days, the EROA dropped from 0.93 ± 0.40 to 0.42 ± 0.11 mm², the regurgitant volume decreased from 97.00 to 43.50 ml, and the 6-minute walk test (6MWT) distance improved from 239.7 to 402.7 m without any major adverse events.

In concrete terms, for the practitioner:

• Surgical alternative: Percutaneous annuloplasty is emerging as a viable option for symptomatic patients at high surgical risk (mean STS score of 6.7).
• Rapid functional impact: Expect a notable improvement in quality of life (KCCQ scores and NYHA class) from the first month post-procedure.
• Clinical caution: Although promising, these results are based on a very small sample size (N=4); the reproducibility of this technical success and the durability of the benefits have yet to be confirmed in larger cohorts.

Technical lexicon

Percutaneous annuloplasty: Technique for reducing the diameter of the tricuspid annulus performed via an endovascular approach without the need for thoracotomy.

Vena contracta (VC): The narrowest segment of a regurgitant jet, used as a measure of the severity of valvular leakage.

EROA (Effective Regurgitant Orifice Area): Effective regurgitant orifice area, a major quantitative parameter for assessing the severity of tricuspid regurgitation.

STS (Society of Thoracic Surgeons) Score: Validated scoring system used to estimate the risk of mortality and complications at 30 days following cardiac surgery.

TAPSE (Tricuspid Annular Plane Systolic Excursion): Echocardiographic parameter measuring the longitudinal excursion of the tricuspid annulus, reflecting the systolic function of the right ventricle.

KCCQ (Kansas City Cardiomyopathy Questionnaire): Heart failure-specific questionnaire assessing the impact of the disease on the patient's physical, social, and psychological status.

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