NeoChord DS1000: what durability for beating heart repair?

NeoChord DS1000: Real-world durability evaluation beyond immediate success

Beating-heart mitral valve repair via the NeoChord DS1000 system has emerged as a minimally invasive alternative for the treatment of degenerative mitral regurgitation (MR), particularly for P2 segment prolapse. However, although initial procedural safety seems established, mid-term functional durability remains a point of vigilance for cardiac surgeons. This single-center study addresses the issue of MR recurrence, a phenomenon sometimes underestimated by traditional cross-sectional analyses.

The specific objective of this retrospective study conducted on 31 consecutive patients (2016-2022) was to evaluate survival without recurrence of moderate or severe mitral regurgitation (grade ≥ 2) using survival analysis (Kaplan-Meier). The authors sought to quantify the long-term durability of the device over a two-year period while isolating the influence of the surgical learning curve.

The study is based on the hypothesis that the durability of the NeoChord DS1000 system is closely linked to team experience and the rigor of anatomical selection. By comparing the first 16 procedures with the subsequent 15, the authors test whether more refined patient selection and increased technical expertise allow for the stabilization of hemodynamic results over the long term.

Methodology: Retrospective analysis and learning curve

This single-center retrospective study included 31 consecutive patients treated between 2016 and 2022 for severe degenerative mitral regurgitation (MR) (grade 3–4). The population was characterized by:

• Clinical profile: Mean age 57.1 ± 14.0 years, 87.1% male and 71.0% low surgical risk patients (EuroSCORE II < 2).
• Valvular anatomy: Predominant involvement of the P2 segment in 90.0% of cases.

The experimental protocol was based on beating-heart transapical mitral valve repair using the NeoChord DS1000 system. To evaluate the impact of surgical experience, the authors compared the results of the first 16 procedures with those of the subsequent 15 (learning curve).

The analysis methods favored a "time-to-event" approach:

• Primary endpoint: Absence of recurrence of moderate or greater MR (grade ≥ 2).
• Statistical tools: Durability estimation by Kaplan-Meier analysis at 3 months, 1 year, and 2 years.
• Clinical follow-up: Systematic echocardiographic evaluations at hospital discharge and during the mid-term follow-up period.

Technical success and perioperative safety

Implantation of the NeoChord DS1000 system showed a 100% procedural success rate across the entire cohort (n=31). The mean operative time was 122.2 ± 14.3 minutes. Short-term safety is excellent: no perioperative or 30-day mortality was recorded. The most notable postoperative complication was the occurrence of de novo atrial fibrillation in 9.7% of patients.

Durability and recurrence-free survival analysis

Although 96.8% of patients were discharged with residual mitral regurgitation (MR) ≤ grade 1, the Kaplan-Meier analysis (time-to-event) reveals a progressive degradation of valve competence during follow-up. The recurrence-free survival rate for moderate or severe MR (grade ≥ 2) is as follows:

• At 3 months: 93.5%
• At 1 year: 77.4%
• At 2 years: 66.9%

Only one patient (3.2%) required conventional surgical reintervention due to chordal rupture. The study highlights that mid-term durability appears more limited than suggested by classic cross-sectional reports.

Learning curve and success factors

Comparative analysis between the first half of the experience (first 16 procedures) and the second (last 15) shows a trend toward improved durability of results in the second group. This observation suggests a significant learning curve effect for mastering chordal tensioning on a beating heart. The authors specify that the best results were observed in patients with isolated P2 segment pathology (90.0% of the cohort), confirming the importance of rigorous anatomical selection for this transapical technique.

Undeniable initial efficacy, durability to be monitored

The results of this single-center study highlight a clinical paradox specific to the NeoChord DS1000 technique: remarkable perioperative safety contrasting with an erosion of hemodynamic performance in the mid-term. With 100% procedural success and zero 30-day mortality, the beating-heart transapical approach stands out as an ultra-safe option for low surgical risk patients (EuroSCORE II < 2 in 71% of cases). However, the Kaplan-Meier analysis reveals a more nuanced reality: while 96.8% of patients are discharged with mitral regurgitation (MR) ≤ grade 1, the survival rate free from moderate or severe MR drops to 66.9% after only two years.

This difference between classic cross-sectional reports and the "time-to-event" analysis suggests that the durability of artificial chordal repair is more fragile than expected. However, the study highlights a tangible learning effect: durability improves significantly over the last 15 procedures of the series. This confirms that technical mastery and precise positioning of the chords are critical determinants of long-term results.

The limitations lie mainly in the modest size of the cohort (n=31) and the retrospective design. Nevertheless, the observation of only one reintervention for chordal rupture (3.2%) over two years shows that, despite the recurrence of some reflux, the overall structural stability remains acceptable.

Summary of results

In 31 patients (mean age 57.1 years), the NeoChord DS1000 system demonstrates exemplary intraoperative safety with 100% technical success and zero 30-day mortality. Nevertheless, survival analysis reveals an erosion of durability: the rate of absence of mitral regurgitation (MR) ≥ grade 2 drops from 93.5% at 3 months to 66.9% at 2 years, despite excellent initial results (96.8% of MR ≤ grade 1 at discharge).

Concretely, for the practitioner:

• Refine selection: Prioritize patients with favorable anatomy (isolated P2 prolapse) to maximize the chances of durable success.
• Manage the learning curve: The results of this study show an improvement in durability during the second half of the series; structured and regular practice is therefore essential.
• Systematic echocardiographic monitoring: Maintain rigorous follow-up beyond the first year to detect early recurrences of MR, which conventional cross-sectional reports tend to mask.

Technical glossary of the study

NeoChord DS1000: Minimally invasive mitral repair device designed for the implantation of artificial ePTFE chords via a transapical approach, without the need for cardiopulmonary bypass.

Transapical (approach): Surgical technique consisting of accessing the mitral valve via an incision at the apex of the left ventricle for the insertion and manipulation of intracardiac instruments.

Time-to-event (analysis): Statistical method, using the Kaplan-Meier curve here, to evaluate the time until the occurrence of a recurrence of moderate or severe mitral regurgitation (grade ≥ 2).

EuroSCORE II: Risk assessment system for operative mortality in cardiac surgery; 71% of the cohort presented a low-risk profile with a score of less than 2.

Beating-heart: Surgical procedure performed on the functioning heart, avoiding induced cardiac arrest and the risks associated with cardiopulmonary bypass and aortic cannulation.

P2 segment: Central part of the posterior mitral leaflet, identified as the predominant zone of degenerative pathology in 90% of the patients in this study.

Chordal rupture: Postoperative mechanical complication reported in one patient (3.2%) who required surgical reintervention during follow-up.

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