Degenerative mitral regurgitation (DMR) is a prevalent cardiac condition and represents one of the most frequent indications for mitral valve surgery in developed countries. In recent decades, mitral valve repair (MVr) has emerged as the preferred treatment strategy over valve replacement due to its superiority in preserving left ventricular function, reducing thromboembolic risk, avoiding prosthesis-related complications, and improving long-term survival. This paradigm shift has been supported by numerous studies demonstrating durable outcomes and favorable hemodynamics following repair, particularly in patients with isolated leaflet prolapse or flail (1–4).

Anterior leaflet prolapse or flail, while less common than posterior leaflet disease, presents unique surgical challenges due to the intrinsic mobility and length of the anterior leaflet and the complexity of achieving adequate coaptation. Successful repair in such cases often relies on the use of artificial chordae tendineae, typically constructed from expanded polytetrafluoroethylene (ePTFE), which provide a durable alternative to leaflet resection and preserve leaflet tissue. However, despite their advantages, a key limitation of artificial chordae is the difficulty of accurately determining the appropriate chordal length intraoperatively, which directly impacts the quality of the repair and its long-term durability (5–7).

Traditionally, chordal length estimation has depended on visual approximation, traction testing, or the saline test to simulate ventricular pressurization. These methods are subjective, operator-dependent, and may be affected by inter-patient anatomical variability and intraoperative conditions. Moreover, these approaches do not allow for real-time measurement under physiological loading conditions, leading to potential discrepancies in coaptation and leaflet tension. Inconsistent outcomes may contribute to early residual mitral regurgitation (MR), increased reintervention rates, and reduced repair durability.

To overcome these limitations, several innovations have been introduced. Techniques such as the loop technique, premeasured chords, and template-guided implantation have attempted to standardize neo-chordal length. Notably, the Chord-X system offers pre-measured loops of varying lengths to facilitate implantation and has demonstrated promising results, particularly in low-volume surgical centers and in minimally invasive settings. Similarly, the Leipzig Loop technique, the loop-in-loop method, and papillary muscle relocation have been explored. While effective, these approaches may still require experience or auxiliary instrumentation and may not be universally applicable or reproducible (8–10).

In this context, we previously introduced the “track technique” as a novel and standardized approach for artificial chordae length determination. This method utilizes a temporary annular guiding device inserted after the annuloplasty ring placement. The guide establishes a consistent reference point for chordae anchoring and eliminates the need for ventricular pressurization or subjective caliper-based measurement. Early results demonstrated that the track technique produced more uniform coaptation lengths and reduced early residual MR when compared to conventional estimation methods (11).

Although preliminary data from short-term follow-up were encouraging, long-term outcomes and durability of the track technique remained to be confirmed. This study builds upon our prior observations and presents a 5-year comparative analysis of the clinical and echocardiographic results of the track technique vs. a conventional visual estimation method in patients undergoing MVr for anterior leaflet prolapse or flail. In doing so, we aim to provide robust evidence supporting the technique's long-term efficacy, reproducibility, and suitability for broader clinical adoption.

In this setting, the need for reproducible and efficient intraoperative techniques is amplified by the rising demand for minimally invasive approaches. As more centers adopt robotic and video-assisted MVr, the ability to execute high-quality repairs with limited exposure becomes increasingly dependent on standardized tools and approaches such as the track technique (12–16).

This retrospective observational study was conducted at a single high-volume mitral center, Anthea Hospital – GVM Care & Research - and adheres to the STROBE guidelines for observational studies. The study protocol was approved by our Institutional Review Board. IRB numb. 5.2025.

All patients provided informed consent for data collection, analysis, and long-term follow-up. Pre, intra, and postoperative outcomes were compared between the 2 groups. All patients were contacted for a follow-up every year up to a maximum of 5 years. The aim of this investigation was to compare long-term outcomes between two different techniques for artificial chordae sizing during mitral valve repair (MVr) in patients with MR due to anterior leaflet prolapse.

Baseline characteristics were comparable between the two groups (Table 1). The mean patient age was 72.5 ± 4.2 years in the track group and 71.8 ± 3.9 years in the conventional group. All patients presented with isolated anterior leaflet prolapse or flail and underwent surgery through right mini-thoracotomy access in the majority of cases (80% track vs. 77% conventional, p = 0.81). No patients required conversion to valve replacement, and all received a complete annuloplasty ring without any additional surgical techniques.

Intraoperatively, the number of chordae implanted was similar between groups (2.1 ± 0.4 vs. 2.2 ± 0.5, p = 0.61). Aortic cross-clamp and cardiopulmonary bypass times did not differ significantly, indicating procedural feasibility of the track technique (Table 2).

Postoperative outcomes were excellent in both groups, with zero 30-day mortality or major complications such as stroke or wound infections (Table 3). Length of hospital stay averaged 7.2 ± 1.5 days in the track group and 7.5 ± 1.8 days in the conventional group (p = 0.48).

At the 5-year follow-up mark, clinical and echocardiographic assessments were available for 85% of patients (40/47). No patient experienced mitral valve reoperation or developed endocarditis. NYHA class I–II was observed in 96% of patients in the track group and 91% in the conventional group (p = 0.52). Importantly, **residual MR of grade 1+** was significantly less common in the track group (12%) compared to the conventional group (32%, p = 0.04), suggesting better leaflet coaptation. Mean coaptation length, measured via intraoperative or early postoperative transesophageal echocardiography, was 10.7 ± 1.5 mm in the track group vs. 8.6 ± 1.8 mm in the conventional group (p = 0.03) (Table 4; Figure 2).

Further subgroup analysis revealed that patients in the track group showed not only greater coaptation length but also a narrower range of coaptation values (standard deviation: 1.5 mm vs. 1.8 mm), indicating reduced variability in repair outcomes. The mean number of implanted chordae did not differ significantly between groups. No patient in the track group exhibited signs of chordal entanglement or systolic anterior motion (SAM), while two patients in the conventional group required intraoperative adjustment due to suboptimal leaflet motion.

Postoperative left ventricular function, as assessed by echocardiographic ejection fraction, remained stable across follow-up in both groups, indicating that neither technique adversely affected ventricular performance.

Our 5-year comparative analysis confirms the central role of accurate chordal length determination in achieving durable mitral valve repair (MVr), particularly in the challenging setting of anterior leaflet prolapse or flail. While both the track and conventional techniques yielded excellent safety profiles and freedom from moderate or severe mitral regurgitation (MR), the track technique demonstrated superior echocardiographic precision, reflected by a significantly longer and more consistent coaptation length.

Coaptation length is a validated surrogate marker of repair durability (17). Insufficient leaflet coaptation is associated with early MR recurrence and suboptimal leaflet competence, particularly in anterior leaflet disease. Our findings reinforce this link: patients treated with the track technique achieved a mean coaptation length of 10.7 ± 1.5 mm, exceeding that of the conventional group and aligning with biomechanical thresholds previously associated with long-term competence. Furthermore, the narrower standard deviation in the track group (1.5 mm vs. 1.8 mm) indicates enhanced reproducibility and reduced inter-operator variability—critical goals in modern cardiac surgery. This consistency may translate into better long-term durability and fewer late reinterventions, although longer follow-up is needed.

While the mean number of implanted chordae did not differ significantly between groups, qualitative assessment suggested that the track technique facilitated more symmetric chordal tensioning and leaflet alignment. No patient in the track group exhibited signs of chordal entanglement or systolic anterior motion (SAM), while two patients in the conventional group required intraoperative adjustment due to suboptimal leaflet motion.

Postoperative left ventricular function, as assessed by echocardiographic ejection fraction, remained stable across follow-up in both groups, indicating that neither technique adversely affected ventricular performance. However, the improved coaptation seen in the track group may support more physiological leaflet motion and mitral competence over time.

Several strategies have been proposed to standardize neochordae length, including pre-measured loops (e.g., Chord-X), loop-based techniques (Leipzig loop/loop-in-loop), and template/caliper-guided sizing; robot-assisted measured-tube systems have also been described. While effective, these approaches may rely on preformed loop sizes, auxiliary instrumentation, or robotic platforms and therefore can have limited granularity or availability. In contrast, the track technique uses the annular plane after complete annuloplasty as a fixed reference, does not require ventricular pressurization, and is platform-agnostic (mini-thoracotomy or sternotomy). In our series, this translated into longer and more consistent coaptation compared with conventional visual estimation.

Recent studies have emphasized the importance of standardized techniques to achieve consistency in MVr outcomes. Tomsi et al. (18) reported that standardized procedural pathways significantly improved postoperative recovery and reduced adverse events, especially in elderly patients undergoing minimally invasive MVr. Our findings suggest that the track technique, by eliminating subjectivity and anchoring chordal length to an anatomical landmark, aligns well with such structured approaches and may help extend high-quality repair outcomes beyond high-volume centers.

While chordal replacement with expanded polytetrafluoroethylene (ePTFE) has become well-established, recent long-term data reinforce its durability when precise length control is achieved. McCarthy et al. (19) demonstrated low rates of MR recurrence and excellent valve function beyond 8 years post-repair, underlining the value of reproducible chordal implantation. These outcomes mirror our own and support the premise that repair success hinges not only on materials used, but on geometric precision during implantation.

To this end, innovations in robotic and device-assisted chordal sizing have emerged. Tedoriya et al. (14) introduced the “measured tube technique”, using a calibrated delivery system during robotic MVr to predefine chordal length. While technologically sophisticated, such systems require robotic platforms and specific instrumentation. In contrast, the track technique provides similar accuracy without dependence on robotics, making it more accessible to a broad range of surgical teams.

Emerging technologies such as augmented reality (AR) and 3D intraoperative imaging are also shaping the future of MVr. Moon et al. (15) demonstrated that AR enhances surgical planning and anatomic orientation, potentially aiding complex repairs. While not yet integrated into routine practice, such tools could complement the track technique by providing enhanced visual feedback and augmenting intraoperative confidence, particularly in minimally invasive or robotic environments.

From a biomechanical perspective, optimal chordal length achieves symmetric leaflet motion, reduces chordal stress, and maximizes coaptation. Rin et al. (16) used finite element modeling to show that even submillimetric discrepancies in chordal length disrupt stress distributions and coaptation geometry. This computational evidence provides mechanistic validation for the track technique, which leverages a fixed annular reference to achieve consistent geometrical alignment across diverse anatomies.

Beyond clinical outcomes, the track technique has educational value. Its intuitive, pressurization-independent methodology offers a reproducible learning curve for junior surgeons. Unlike visual or saline-based estimation, it minimizes subjective interpretation, fostering surgical confidence and skill acquisition. As the demand for MVr grows in less experienced centers, the dissemination of simple yet effective techniques becomes critical for ensuring repair quality and patient safety.

In summary, this 5-year follow-up study confirms that the track technique not only matches conventional methods in safety but also provides superior coaptation geometry, reduced variability, and long-term MR suppression. The integration of recent evidence—from device innovations and AR to computational biomechanics—reinforces the importance of precision in neo-chordal implantation. The track technique, with its simplicity, anatomical logic, and reproducibility, may serve as a benchmark for standardized, high-quality mitral repair across varied surgical platforms.

In this 5-year analysis of mitral valve repair (MVr) for anterior leaflet prolapse or flail, the track technique showed excellent durability and superior echocardiographic outcomes compared to conventional chordal length estimation. It resulted in longer, more consistent coaptation and less residual mitral regurgitation.

The technique offers procedural advantages by eliminating the need for intraoperative pressurization or subjective assessments, making it especially valuable in minimally invasive and robotic settings. Its standardization enhances reproducibility, supports training in lower-volume centers, and reduces operator dependence.

By providing objective anatomical guidance, the track technique facilitates skill acquisition and may contribute to more uniform surgical quality. As mitral repair trends toward minimally invasive and precise methods, this technique aligns with future demands for scalable, reliable solutions.