Totally endoscopic mitral valve repair with novel technique of left atrial exposure: five years experience from a single center

Abstract

Background

.Endoscopic mitral valve repair has progressively been adopted as the standard approach for treating isolated mitral regurgitation across numerous renowned cardiac surgery centers worldwide. Our innovative method for mitral valve exposure has been previously described. This study evaluates the outcomes of totally endoscopic mitral valve repair using this advanced technique over a five-year period at a single center.

Methods

. A retrospective review was conducted on 122 patients who underwent totally endoscopic mitral valve repair between May 2018 and December 2023. Clinical and echocardiographic data were meticulously collected and analyzed. The surgical procedure was performed completely endoscopic via a 3–4 cm right mini-thoracotomy, with peripheral cardiopulmonary bypass. A specialized technique utilizing retraction sutures for mitral valve exposure was employed. Primary outcomes included the results of the endoscopic techniques, mitral valve repair outcomes, perioperative complications, and short-term mortality. Long-term outcomes, including survival, freedom from reoperation, and recurrent mitral regurgitation, were assessed using Kaplan–Meier analysis.

Results

. Mitral valve exposure was successfully achieved in all cases. The mean age of the patients was 54.5 ± 14.2 years, and their mean log EuroSCORE II was 1.53 ± 1.30. The repair rate was 96%, with anterior leaflet repair in 13%, posterior leaflet repair in 69%, and bileaflet repair in 14%. Mean aortic cross-clamp time and cardiopulmonary bypass time were 117 ± 39 min and 181 ± 48 min, respectively. The early mortality rate was 1.6%. Three patients (2.5%) experienced intraoperative conversion to sternotomy and 6 patients (4.9%) underwent a reoperation. There were 2 cases of stroke (1.6%) and 2 cases of unilateral pulmonary edema (1.6%). The minimum follow-up duration for a patient was 6 months, extending up to 72 months, with a mean follow-up duration of 28.6 ± 15.1 months. Kaplan–Meier analysis demonstrated a 96.7 ± 1.6% survival rate at 5 years, with 98.4 ± 1.2% freedom from reoperation, and 86.1 ± 3.1% freedom from recurrent mitral regurgitation.

Conclusions

. Totally endoscopic mitral valve repair utilizing the novel technique of left atrial exposure is feasible and can be safely performed with low mortality and morbidity. This approach achieves a high rate of mitral repair and demonstrates favorable long-term outcomes.

Introduction

Endoscopic mitral valve repair has marked significant milestones in cardiac surgery, offering benefits such as reduced postoperative pain, fewer blood transfusions, shorter ventilation times, reduced lengths of stay in the intensive care unit (ICU) and hospital, improved cosmetic outcomes, and the elimination of the risk of sternitis [1, 2]. Additionally, continuous advancements in technology and surgical instruments, including the introduction of the 3D endoscopic system and the refinement of surgical tools, have substantially enhanced the effectiveness of the procedure.

In our department, endoscopic mitral valve repair has gained increasing popularity and has become the standard for treating isolated mitral regurgitation (MR). Both short-term and long-term results have been promising, demonstrating the procedure’s safety and efficacy.

A critical factor in the success of surgery is the clear exposure of the mitral valve. Among various methods, we have developed and implemented a unique technique for mitral valve exposure. This innovative approach, in line with those reported in previously published studies, has significantly improved our surgical results and patient outcomes [3].

This study aims to evaluate the feasibility, safety, and long-term outcomes of totally endoscopic mitral valve repair (TEMVR) utilizing this technique for left atrial exposure, based on five years of experience from a single center.

Materials and methods

Patient selection and data collection

This is a retrospective, observational study that collected data from 122 consecutive patients who underwent TEMVR for the treatment of isolated MR between May 2018 and December 2023. Isolated MR was defined as mitral regurgitation diagnosed without concurrent stenosis [4]. Indications for TEMVR included severe MR accompanied by symptoms of heart failure, signs of left ventricular dysfunction, or left ventricular dilation. Exclusion criteria included patients older than 80 years; EuroSCORE II greater than 10%; BMI exceeding 35; chest deformities (such as pectus excavatum and pectus carinatum); spinal deformities (including kyphosis and scoliosis); concomitant coronary artery disease requiring coronary artery bypass grafting; moderate to severe aortic valve regurgitation; ascending aorta aneurysm, dissection, severe calcification, or dilation greater than 45 mm; severe calcification or stenosis of the descending aorta, abdominal aorta, or iliac arteries; severe peripheral arterial disease; right lung adhesions due to prior thoracic surgery, chest radiation, or trauma; redo cardiac surgeries; patients requiring emergency surgery; and infective endocarditis with mitral annulus abscess.

Patient demographics, medical history, and operative and in-hospital outcomes were meticulously documented at the time of each patient’s admission and during subsequent follow-up visits. All patients underwent intraoperative transesophageal echocardiography to evaluate the success of the valve repair.

Early outcomes assessed included mortality (defined as any death occurring within 30 days post-operation or prior to hospital discharge), failure of the endoscopic technique, perioperative complications, and the rate of successful repair. Late follow-up was defined as exceeding 6 months. Long-term outcomes included mortality, freedom from recurrent MR and reoperation. Patients were evaluated every 4 weeks during the first 6 months post-surgery, and subsequently every 6 months. In instances of more than moderate MR, follow-up was conducted every 1–3 months based on the severity and symptomatic presentation. Recurrent MR was classified as moderate or severe using a 4-point grading scale (trivial, 1; mild, 2; moderate, 3; severe, 4).

All patients had a minimum follow-up period of 6 months. The median follow-up duration was 28.6 ± 15.1 months (interquartile range, 6–72 months). Patients lost to follow-up or who could not be monitored were excluded from the study.

This study received approval from the ethics review committee of the Department of Cardiovascular and Thoracic Surgery and the hospital’s ethics committee, which waived the requirement for informed consent due to the study’s retrospective nature.

Surgical technique

This protocol provides a detailed methodology on performing TEMVR using our specialized technique for mitral valve exposure. Induction of conventional general anesthesia was achieved using double-lumen or single-lumen tracheal intubation. The patient was positioned supine with the right side elevated to a 30-degree angle by placing a pillow beneath the axilla. The right upper limb was positioned parallel to the body with the elbow joint slightly flexed to fully expose the right lateral chest. A transesophageal echocardiography probe was inserted, and two external defibrillator pads were placed on the back. Peripheral cardiopulmonary bypass (CPB) was established via the right femoral artery, femoral vein, and right internal jugular vein.

A primary working port was created at the fourth or fifth intercostal space (ICS) with a 3–4 cm incision extending from the mid-axillary line to the anterior axillary line on the right side. Following the incision, a soft tissue retractor was inserted to avoid damage to the ribs and surrounding structures. This working port accommodated all surgical instruments, the cardioplegia needle, the left venting line, and the CO₂ insufflator. A 10-mm trocar for a 3D endoscope (Karl Storz, Tuttlingen, Germany) was inserted through either the fourth or fifth ICS, positioned at the right mid-axillary line. The ascending aorta was cross-clamped using a transthoracic Chitwood clamp through the third ICS at the anterior axillary line. Cardiac arrest was induced by delivering cardioplegia into the ascending aorta.

Upon achieving cardiac arrest, the left atrium was incised, and the mitral valve was exposed utilizing the following retraction sutures: Four 3/0 or 4/0 polypropylene sutures were employed to retract the walls of the left atrium. The sutures were placed at the interatrial septum at the 10 o’clock, 12 o’clock, and 2 o’clock positions, each at least 2 cm away from the anterior mitral annulus. The needles were then threaded through either the pericardium or the anterior thoracic wall, exiting through the working port. This retraction sutures of the interatrial septum provided excellent exposure of the anterior mitral annulus and the lateral trigon. Once these sutures were secured to the surgical drape, the exposure remained stable throughout the entire procedure. An additional suture was placed either at the floor or the posterior wall of the left atrium, then threaded through the right diaphragm. This suture afforded enhanced exposure of the posteromedial commissural area by retracting the left atrium with the posterior annulus. This technique facilitated accurate placement of annuloplasty sutures and minimized the risk of injury to the circumflex artery, which curves towards the posterior mitral annulus. Moreover, this approach brought the mitral valve plane closer to the surgeon, allowing for more space and improved surgical maneuverability (Figs. 1 and 2).

Fig. 1

Intraoperative Setup: (A) Chitwood clamp, (B) 3D endoscopic camera, (1–5) Retraction sutures

Fig. 2

Complete exposure of the mitral valve using retraction sutures

Once optimal exposure of the mitral valve was achieved, standard mitral valve repair techniques were employed. The repair was conducted under complete 3D endoscopic visualization using standard minimally invasive cardiac surgery instruments.

Statistical analysis

This study was designed as a retrospective analysis, with data presented as mean ± standard deviation. Survival and event-free estimates were determined using Kaplan-Meier analysis. All Kaplan-Meier analyses were conducted on the total patient cohort of 122 individuals. Three patients who underwent immediate intra-operative conversion to sternotomy were censored on the day of surgery. Statistical analyses were performed using SPSS version 24.0, with P-values < 0.05 considered indicative of statistical significance.

Results

The baseline characteristics of the patient cohort are listed in Table 1. The mean age was 54.5 ± 14.2 years, and 62% of the patients were male. The mean Body Mass Index was 21.88 ± 3.02 kg/m². Within the cohort, 70.5% had a normal BMI, 13.1% were underweight (BMI < 18.5), 15.6% were overweight (BMI 25-29.99), and 0.8% were classified as obese (BMI ≥ 30). The mean preoperative left ventricular ejection fraction was 69.7 ± 9.9%. The most predominant pathology was degenerative disease (n = 109, 89%), followed by endocarditis (n = 13, 11%). The complexity of mitral valve lesions was categorized as simple (72%), complex (12%), and highly complex (16%). The EuroSCORE II analysis indicated a mean score of 1.53 ± 1.30, with 13.1% of patients classified as low risk, 74.6% as medium risk, and 12.3% as high risk.

Table 1 Baseline patient profiles

Mitral valve repair

Among the 122 candidates for mitral valve repair, 117 (95.9%) underwent successful repairs, while 5 (4.1%) required valve replacement following an attempted repair. The predominant technique employed was annuloplasty, utilized in 109 patients (89.3%). For anterior leaflet repair, the main technique was chordae replacement, performed in 14 patients (11.5%). Posterior leaflet repair was the most frequently performed procedure, applied in 85 patients (69.7%). The main approaches for posterior leaflet repair included triangular resection in 28 patients (23.0%), quadrangular resection in 24 patients (19.7%), and folding repair in 27 patients (22.1%). Bileaflet repair was conducted in 17 patients (13.9%), utilizing techniques such as Alfieri edge-to-edge in 2 patients (1.6%), plication commissure in 8 patients (6.6%), chordae replacement in 4 patients (3.3%), and leaflet resection in 6 patients (4.9%). Postoperative outcomes indicated minimal residual MR at discharge, with 64 patients (55.2%) exhibiting no MR, 43 patients (37.1%) presenting with mild MR, and 9 patients (7.7%) showing moderate MR. Notably, no patients had severe MR at discharge (Table 2).

Table 2 Mitral valve repair techniques

Intraoperative findings

The learning curve associated with CPB time and aortic cross-clamp time across consecutive operations is illustrated in Figs. 3 and 4, respectively. In Fig. 3, the mean CPB time was 181 ± 48 min, with a range from 104 to 338 min. The scatter plot, accompanied by a red trend line, demonstrates a consistent reduction in CPB time over the series of operations, reflecting enhanced efficiency and proficiency. Similarly, Fig. 4 shows a mean aortic cross-clamp time of 117 ± 39 min, ranging from 54 to 255 min. The trend line in the scatter plot signifies a decrease in cross-clamp times with increased surgical experience.

Fig. 3

Learning curve: trends in CPB Time across consecutive operations

Fig. 4

Learning curve: trends in aortic cross-clamp time across consecutive operations

Several intraoperative observations were recorded: right pleural adhesions were identified in 5 patients (4.1%) and pericardial adhesions were observed in 1 patient (0.8%). Among these cases, 3 patients presented with severe pleural adhesions that could not be safely dissected, necessitating conversion to sternotomy (2.5%). Additionally, one patient experienced a complication during the establishment of peripheral CPB, resulting in a perforation of the right internal jugular vein (0.8%). Furthermore, one patient developed systolic anterior motion (SAM) following mitral valve repair (0.8%), necessitating immediate intraoperative re-repair of the valve (Table 3).

Table 3 Intraoperative details

Early outcomes

The early postoperative outcomes are presented in Table 4. The median ventilation time was 15 h, with an interquartile range (IQR) of 10 to 59 h. The median length of stay in the ICU was 2 days, with an IQR of 2 to 4 days. In terms of blood loss and transfusion requirements, 20 patients (16.4%) necessitated blood transfusions, with an average of 0.8 units of red blood cells (RBC) transfused per patient. The median volume of blood loss through drainage was recorded at 300 ml. Several early postoperative complications were documented. The mortality rate was 1.6% (2 patients). Reoperation was required in 5 patients (4.1%) due to bleeding and in 1 patient (0.8%) due to hemolysis. Cerebrovascular accidents (strokes) occurred in 2 patients (1.6%), while new onset atrial fibrillation was observed in 5 patients (4.1%). Renal failure was reported in 6 patients (4.9%), and unilateral pulmonary edema (UPE) was noted in 2 patients (1.6%).

Table 4 Early outcomes

Late outcomes

Excluding the 2 early mortality cases, 120 out of 122 patients were followed up regularly for a minimum of 6 months and a maximum of 72 months, with a total follow-up duration of 3408 months and a mean follow-up period of 28.6 ± 15.1 months. The Kaplan-Meier curves demonstrated favorable long-term outcomes for TEMVR. The cumulative survival rate at 72 months was 96.7% ± 1.6%. Freedom from reoperation over the 5-year period post-TEMVR was 98.4% ± 1.2%. For patients who underwent mitral valve repair, freedom from recurrent MR was 86.1% ± 3.1% at the end of the follow-up period (Figs. 5, 6 and 7).

Fig. 5

Cumulative survival probability over time following surgery

Fig. 6

Long-term cumulative freedom from reoperation following TEMVR

Fig. 7

Long-term cumulative freedom from recurrent MR following TEMVR

Discussion

The advent of minimally invasive mitral valve surgery has conferred numerous benefits to patients. The demand for such less invasive procedures is steadily increasing, driven by the imperative to reduce patient morbidity and enhance recovery. This trend is facilitated by continuous advancements in technology and surgical instruments, all aimed at improving the safety and efficacy of surgery.In this study, we investigated the use of totally 3D endoscopic surgery for mitral valve repair, with a focus on both early and long-term outcomes. Additionally, we examined the feasibility and impact of our innovative valve exposure method, which introduces a meaningful improvement in surgical technique and access to the mitral valve.

Our retraction suture approach offers notable advantages over traditional trans-thoracic retractors. By eliminating the need for a metal bar through the chest wall, this technique minimizes the risk of injury to mammary and intercostal vessels. The retraction sutures provide stable, uninterrupted exposure throughout the procedure, which supports a more streamlined surgical workflow. Regarding surgical time, retraction sutures are particularly efficient. They can be placed during cardioplegia delivery, utilizing approximately 3–5 min without extending the overall operative duration. In patients with challenging anatomy—such as a small or leftward-deviated left atrium, a deep thoracic cavity, or chest conditions like pectus carinatum or pectus excavatum—achieving adequate exposure with conventional retractors can be difficult. Our method allows for flexible suture placement in areas that may otherwise be obstructed, thereby enhancing visibility and reducing potential complications associated with limited access in such complex cases [3].

In our study, the mitral valve repair rate was 96%, with 5 cases (4%) necessitating conversion to prosthetic mitral valve replacement. We classified the complexity of mitral valve lesions to evaluate and predict the likelihood of successful mitral valve repair as follows: simple (annuloplasty alone; single leaflet segment lesion), complex (multiple segment lesions on a single leaflet), and highly complex (bileaflet repair or involving multiple complex techniques, e.g., leaflet patch augmentation, chordal transfer, neochordae replacement). The repair rate for simple lesions was 100%. There were 34 cases categorized as complex and highly complex, representing 28% of the cohort, with a successful repair rate of 85% (29 out of 34 patients) in this group. All instances of repair failure were in the complex anterior leaflet group (3.3%) and the highly complex bileaflet group (0.8%), with etiologies including infective endocarditis (2.5%) and degenerative disease (1.6%) (Table 2). Generally, the repair rates in various studies differ significantly, depending on patient selection criteria, lesion morphology, techniques, equipment, and the surgeon’s experience. Based on our experience with 122 patients, we propose that certain lesions may not be suitable for the initial implementation of endoscopic mitral valve repair techniques. These include extensive anterior leaflet prolapse involving multiple segments, bileaflet prolapse without commissural involvement, and infective endocarditis.

One of the key factors in determining the success of mitral repair is the adequate exposure of the valve. Numerous instruments have been developed to achieve optimal exposure of the mitral valve in minimally invasive surgery. During the course of our surgical experience, we evaluated various methods and ultimately selected the most suitable approach based on our specific conditions and accumulated expertise. We employed a technique that exclusively utilizes retraction sutures to achieve mitral valve exposure. The materials used for this technique include 3/0 or 4/0 monofilament polypropylene sutures, which are widely accessible. This approach obviates the need for an additional thoracic wall incision, unlike conventional trans-thoracic retractors, thereby mitigating the risks of chest wall bleeding, internal thoracic artery injury, and iatrogenic damage to the leaflet hinge and the bundle of His. Furthermore, employing these sutures ensures that the surgical field remains unobstructed by retractor systems, thus reducing conflicts with surgical instruments. This exposure method is particularly well-suited for a totally endoscopic field, involving a minimal thoracic incision of 3–4 cm, as per our surgical protocol. In instances where the left atrium is small and deviates leftward, the thoracic cavity is deep, or the chest anatomy is unfavorable (e.g., pectus carinatum or pectus excavatum), obtaining satisfactory exposure with a conventional retractor can be challenging. Our technique enables surgeons to place more sutures and select their positions with greater flexibility in blind spots, thereby enhancing visualization. This method was employed in all patients within our study. Mitral valve exposure was successfully achieved in all repair cases and in the five patients who required valve replacement due to complex lesions, which were not related to inadequate exposure. Notably, there were no complications such as tissue tearing requiring additional sutures, ischemic damage, or conversion to sternotomy due to poor visualization.

Several intraoperative complications were observed. Associated with peripheral CPB, a significant complication occurred when the right internal jugular vein and right subclavian artery were perforated during percutaneous cannulation, resulting in substantial bleeding into the pleural cavity. This rare but severe complication necessitated immediate and meticulous intervention. Simple perforations of the internal jugular vein into the pleural cavity can often be managed with endoscopic assistance. However, the concomitant injury to the right subclavian artery presents a risk of acute exsanguination and inadequate CPB flow, potentially requiring conversion to sternotomy and dissection of the sternoclavicular joint to access and control the subclavian artery injury. Our intraoperative management involved maintaining the cannula within the vessel, temporarily controlling the bleeding by suturing the external surrounding tissue, and introducing a new superior vena cava cannula directly through the main working port. Subsequently, the patient underwent endoscopic mitral valve repair as per standard protocol. Immediately following the completion of the surgery, the patient was transferred to the catheterization laboratory. The internal jugular vein cannula was then removed concurrently with angiographic evaluation, during which an arteriovenous fistula involving the right subclavian artery and internal jugular vein was identified. A covered stent was promptly deployed in the subclavian artery, thereby restoring vascular integrity and achieving hemostasis. This endovascular approach facilitated the successful management of this complex complication without necessitating sternotomy or dissection of the sternoclavicular joint.

In our research, 3 patients (2.5%) required conversion to sternotomy: 2 cases due to severe right pleural adhesions and 1 case due to left atrial appendage injury. In global studies, several causes necessitate conversion to sternotomy, including bleeding, pleural adhesions, and aortic dissection. Bleeding can originate from multiple sources such as the pulmonary artery (due to thoracic aortic cross-clamping) [5], the left atrial appendage (due to Chitwood clamp) [6], the left ventricular apex (during valve testing), and the ascending aorta (direct cannulation) [7]. Additionally, pleural adhesions frequently necessitate conversion to sternotomy. While pleural adhesions can sometimes be predicted based on a patient’s history of tuberculosis, radiation therapy, or prior surgeries, routine preoperative chest X-rays and CT scans may not always accurately identify these risks. Aortic dissection has also been reported in several studies, predominantly associated with balloon occlusion of the aorta or in patients with underlying atherosclerosis or aortic calcification. Other intraoperative challenges include insufficient peripheral CPB flow [8], inadequate valve exposure, and circumflex artery injury [7], all of which have been documented and serve as valuable lessons for surgical practice. The two cases requiring conversion to traditional surgery due to pleural adhesions in our study involved challenging adhesiolysis, which resulted in significant pulmonary and pleural injury during the process. The patient with left atrial appendage injury necessitated conversion to sternotomy for control bleeding. However, with the accumulation of surgical experience over time, we have successfully managed this complication via endoscopy in subsequent mitral valve replacement patients.

The early mortality rate in our study was 1.6%, with all affected patients requiring early reoperation. One patient underwent reoperation on postoperative day 3 due to a rupture of the ascending aorta at the site of the cardioplegia needle insertion. This patient experienced hemorrhagic shock and cardiac arrest, necessitating an emergency sternotomy and replacement of the ascending aorta; however, the patient succumbed 24 h later. The second patient required reoperation on postoperative day 6 due to hemolysis following mitral valve repair (neochordae replacement and annuloplasty). Hemolysis following mitral valve repair is a known complication of prosthetic valve replacement, but its occurrence post-repair is relatively rare and hazardous, with a mortality rate of up to 31%, as reported by Buu Khanh Lam [9]. The mechanisms of hemolysis after mitral valve repair are not fully understood, but several patterns have been proposed, such as fragmentation, collision, rapid acceleration, free jet, and slow deceleration [9, 10]. Despite understanding these mechanisms, predicting and early detection of this complication remain challenging. In our study, the patient underwent reoperation and mechanical mitral valve replacement; however, the patient’s condition deteriorated due to coagulopathy, hemorrhage, multi-organ failure, septic shock, and ultimately died on postoperative day 22.

In our study, two patients (1.6%) experienced complications of unilateral pulmonary edema (UPE). UPE is an infrequent yet life-threatening condition. Renner et al. reported five instances of UPE following minimally invasive mitral valve surgery over an eight-year period, all necessitating immediate Extracorporeal Membrane Oxygenation (ECMO) support [11]. The etiology and pathogenesis of UPE remain ambiguous. Some hypotheses suggest that UPE is a manifestation of permeable pulmonary edema, with prolonged CPB times exacerbating ischemia-reperfusion lung injury [11,12,13]. Tutschka’s research identified prolonged CPB duration, Chronic Obstructive Pulmonary Disease (COPD), preoperative pulmonary hypertension, and severe right ventricular dysfunction as significant risk factors for UPE [12]. Additionally, Keyl emphasized surgical factors, such as the potential for obstruction or stenosis of the right pulmonary vein (caused by excessive traction on the pericardium and sutures used for left atrial exposure) leading to secondary increases in hydrostatic pressure and subsequent right-sided pulmonary edema [13]. In our cohort, one patient required ECMO support due to UPE. Both patients received intensive care management, including the administration of corticosteroids to mitigate the severity of pulmonary edema. The patient on ECMO was successfully weaned off, and both patients achieved full recovery without any residual sequelae.

In terms of early results, echocardiography at discharge revealed no cases of severe MR. Moderate MR was observed in 9 patients (7.7%), mild MR in 37.1%, and no MR in the majority of patients (55.2%). These findings indicate that TEMVR achieves favorable short-term outcomes with a variety of techniques comparable to the conventional sternotomy approach.

For long-term outcomes, there was one case of mortality at 6 months postoperatively due to infective endocarditis on a bioprosthetic mitral valve. The late survival probability over the 5-year follow-up period was 96.7 ± 1.6%. Two patients experienced severe recurrent MR at 6 and 24 months, necessitating reoperation: one underwent repeat mitral valve repair, and the other required valve replacement. Freedom from reoperation after 5 years was 98.4 ± 1.2%. The probability of freedom from moderate or severe MR at 72 months was 86.1 ± 3.1%.

Conclusions

TEMVR represents a highly effective approach, yielding favorable early and long-term outcomes with low mortality and morbidity. The innovative left atrial exposure technique, integrated within a fully endoscopic framework, demonstrates substantial feasibility and safety. This method facilitates a high success rate in mitral valve repair, with excellent early outcomes, minimal recurrence of mitral regurgitation, and a low incidence of reoperation. Future studies across broader patient populations would further substantiate these findings and define the full potential of this approach.

Study limitations

This study included several limitations. Primarily, it is a single-center, retrospective study, which inherently carries the risk of selection bias and may limit the generalizability of the findings to broader populations. Additionally, the absence of a control group undergoing conventional sternotomy precludes direct comparative analysis between the endoscopic approach and traditional surgical methods. Endoscopic mitral valve surgery was only initiated at our center in 2014, and the surgical team’s experience with mitral valve repair was still developing during the study period. This nascent phase of experience may have influenced the outcomes observed. Moreover, the follow-up duration for patients in this study was relatively short, with only a limited number of patients being monitored for more than five years. Extended follow-up periods are essential to comprehensively evaluate the durability and long-term efficacy of the endoscopic mitral valve repair technique.