Mechanisms of recurrent regurgitation after transapical off-pump mitral valve repair with neochord implantation†

Microinvasive mitral valve repair with transapical mitral neochordae implantation

Microinvasive cardiac surgery includes procedures performed off-pump, on the beating heart, with limited or absent skin incision, and those that rely on live imaging techniques. Transapical off-pump beating heart neochordae implantation allows the repair of severe mitral valve regurgitation due to leaflet prolapse or flail with live three-dimensional echo guidance. This procedure has shown good results for up to 5 years and can be considered as a valid alternative to conventional surgery in selected patients with high prediction of success based on clinical and anatomical considerations. The aim of this review is to describe the devices, indications, patient screening process, clinical and echocardiographic results, and future perspectives of this procedure.

First in human neochordae retensioning for recurrence of mitral regurgitation after neochord procedure

The Neochord procedure is a viable option to treat degenerative mitral valve regurgitation in selected patients. Left ventricle reverse remodeling can cause neochord-relative elongation and reprolapse of the treated leaflet, leading to failure. We present a clinical case of extensive ventricle reverse remodeling after neochord implantation and the first-in-man off-pump surgical retensioning of the previously implanted artificial chords.

Microinvasive mitral valve surgery: Current status and status quo

Surgical mitral valve repair, performed either through median sternotomy or minimal invasive approach, presents the gold standard treatment for degenerative mitral valve disease. In dedicated centres, high repair and low complication rates have been established with excellent valve repair durability. Recently, new techniques have been introduced, that allow mitral valve repair to be performed through small surgical incisions and while avoiding cardio-pulmonary bypass. These new techniques, however, conceptually differ significantly when compared to surgical repair and it remains questionable whether they are capable of reproducing the results of surgical treatment.

Case report: Recurrent severe mitral regurgitation due to ruptured artificial chords after transapical Neochord mitral valve repair

Transapical Neochord mitral valve repair has been proven to be a technically safe procedure to correct primary mitral regurgitation (MR). Recurrent MR due to ruptured artificial chords is rare. Here, we present 2 cases of recurrent severe MR due to the detached or partially ruptured artificial chords after the Neochord procedure.

Mitral Valve Re-Repair Due to Chordal Pseudo-Elongation Through Repeated Right Anterior Minithoracotomy

OBJECTIVE

We aim to show the step-by-step surgical technique of mitral valve re-repair by means of a repeated right anterior minithoracotomy in a case of a procedure-related early mitral valve repair failure due to left ventricular positive remodeling and chordal pseudo-elongation.

METHODS

The patient was readdressed to our institution for an early severe mitral valve regurgitation, less than a year after performing a right minithoracotomy mitral valve repair (42-mm annular ring implantation, P2 triangular resection, and P2 neochord positioning). The mechanism was attributed to a positive left ventricle remodeling and neochordal pseudo-elongation. Therefore, we decided to perform a mitral valve re-repair in a redo minimally invasive cardiac surgery. We describe in a video-guided step-by-step fashion the surgical procedure, from the reopening of the right anterior minithoracotomy to the surgical strategy chosen to address the re-repair, guided by the mechanism of the previous repair failure.

RESULTS

We replaced the previously implanted ring with a smaller one and positioned a new polytetrafluoroethylene 4-0 neochord at the P2 level. The patient was discharged home on the fifth postoperative day after an uneventful hospital stay. Predischarge echocardiogram demonstrated undetectable residual mitral valve regurgitation. At 3-month follow-up, echocardiographic and clinical data were encouraging. At 9-month follow-up, the patient endorsed no recurrence of cardiologic symptoms.

CONCLUSIONS

Redo minimally invasive cardiac surgery is a viable option even in case of a mitral valve re-repair due to previous repair failure, especially when procedure related in degenerative mitral disease. Combining the benefits of mitral valve re-repair with those of a minimally invasive surgery may optimize short-term and long-term outcomes.

Quantitative Biomechanical Optimization of Neochordal Implantation Location on Mitral Leaflets during Valve Repair

Objective

Methods

Results

Conclusions

Initial experiences of transapical beating‐heart mitral valve repair with a novel artificial chordal implantation device

Background

Severe mitral regurgitation (MR) is associated with progressive heart failure and impairment of survival. Degenerative MR accounts for most MV repair surgeries. Conventional mitral valve repair surgery requires cardiopulmonary bypass and is associated with significant morbidity and risks. Transapical beating‐heart mitral valve repair by artificial chordae implantation with transesophageal echocardiography (TEE) guidance has the potential to significantly reduce surgical morbidity. We report the first‐in‐human experience of degenerative MR repair using a novel artificial chordae implantation device (Mitralstitch^TM system).

Methods

Ten patients with severe MR underwent transapical artificial chordae implantation using MitralstitchTM system. The procedure was performed through a small left thoracotomy under general anesthesia and TEE guidance. Patients underwent transthoracic echocardiography and other assessments during the follow‐up.

Results

All 10 patients with an average age of 63.7 ± 9.6 years successfully received transapical artificial chordae implantation. Their MR reduced from severe to none or trace in five patients, mild in five patients before discharge. Five patients received one artificial chordal implantation, four patients received two, and one patient received three and edge‐to‐edge repair by locking two of them. The safety and efficacy endpoint were achieved in all patients at 1‐month follow‐up. At 1‐year follow‐up, six patients had mild MR, three patients had moderate MR, one patient had recurrence of severe MR and underwent surgical repair.

Conclusions

The results of this first‐in‐human study show safety and feasibility of transapical mitral valve repair using MitralStitch system. Patient selection and technical refinement are crucial to improve the outcomes.

Actual perspective on off-pump transapical artificial chord implantation

Mitral valve repair (MVR) is undisputedly associated with better clinical and functional outcomes than any other type of valve substitute. Conventional mitral valve surgery in dedicated high-volume centers can assure excellent results in terms of mortality and freedom from mitral regurgitation (MR) recurrence but requires cardiopulmonary bypass (CPB) and cardioplegic heart arrest. Trying to replicate the percentage of success of surgical MVR is the aim of all new transcatheter mitral dedicated devices. In particular, transapical beating-heart mitral valve repair by artificial chordae implantation with transesophageal echocardiography guidance is an expanding field. The safety and feasibility of the procedure have already been largely demonstrated with Neochord and more recently with Harpoon systems. Wang et al. present the outcomes of the first-in-human experience using a novel artificial chordae implantation device, the Mitralstitch system. Despite a quite small cohort of only 10 patients treated, 1-year results are satisfying and comparable with the early experience with former devices (4 patients with moderate or more MR recurrence). The comparison with surgical MVR is still unfavorable and requires further studies and significant procedure improvement. However, the device permits the treatment of anterior and posterior leaflets prolapse and performs quite easily edge-to-edge reparation. It will be interesting to evaluate longer follow-up in larger cohorts of patients as well as the possibility to shift to the transfemoral approach.

Transapical off-pump mitral valve repair with NeoChord™ implantation: An early single-center Portuguese experience

INTRODUCTION

Transapical off-pump NeoChord DS1000™ implantation is a minimally invasive surgical mitral valve repair (MVr) procedure to treat degenerative mitral regurgitation (MR), which is performed using the NeoChord DS1000™ system with two and three-dimensional transesophageal echocardiographic guidance on a beating heart. It has been demonstrated to be safe and effective in carefully selected patients.

OBJECTIVE

The authors aim to analyze short-term clinical and echocardiographic results after mitral valve repair using the NeoChord™ system.

METHODS

All patients that underwent transapical off-pump mitral valve repair with NeoChord™ implantation at our center, between December 2017 and December 2019, were included. The procedure was performed by left minithoracotomy, under general anesthesia. All patients presented severe primary MR due to flail/prolapse of one leaflet (anterior or posterior).

RESULTS

Eighteen patients were included in the analysis, the mean age was 65±15 years, 72% were male. The mean EuroSCORE II was 1.9±1.6. All patients had New York Heart Association (NYHA) class ≥ II. Mean effective regurgitant orifice area was 1.0±0.4 cm², with a mean regurgitant volume 146±42 mL, and a mean leaflet-to-annulus index of 1.29±0.14. MR was due to leaflet prolapse in 50% (N=9), and flail leaflet in 50% (N=9). Anatomic type A (isolated P2 defect) was the predominant form in 66.5% (N=12). Successful repair, defined by none, trace or mild mitral regurgitation, by implantation of two to four neochordae, was achieved in all 18 patients. No major complications arose intra-procedurally. The median follow-up was 194 days. NYHA class was ≤II in 94.5% patients at six-month follow-up, which represented a significant improvement in symptomatic status (p=0.002). At follow-up, 72% of patients (N=13) had grade ≤2 MR. There was a significant reduction in mean indexed left atrium volume (63±7 mL/m² vs. 45±6 mL/m², p=0.038), mean indexed left ventricular end-diastolic volume (87±7 mL/m² vs. 79±9 ml/m², p=0.001), and pulmonary arterial systolic pressure (44±4 vs. 31±8 mmHg, p=0.002). The re-intervention rate was 11.1% (N=2, both patients underwent reintervention, either a re-do NeoChord™ or conventional MV repair on-pump surgery). No major adverse cardiac or cerebrovascular events were registered.

CONCLUSIONS

In selected patients, minimally invasive MVr using the NeoChord™ system is safe, effective and reproducible. Early clinical and echocardiographic results suggest a significant symptomatic improvement, sustained MR grade decrease, and favorable left cardiac chamber remodeling, with low re-intervention rates. These results warrant further confirmation in larger cohorts, on longer period of follow-up.

DOUBLE TRANS-APICAL ACCESS DURING NEOCHORD IMPLANTATION

Mitral valve repair using trans-apical off-pump beating-heart neochordae implantation is a relatively new procedure with promising early and mid-term results in selected patients. However early failures few days after the procedure, requiring surgical reintervention, have been described. We describe a case of intraoperative acute procedural failure treated with a second procedure through a different trans-apical access adjacent to the first one. The final result was excellent with trivial residual regurgitation and the subsequent hospitalization was uneventful. This case demonstrates that a second trans-apical mitral neochordae implantation is feasible and should be considered in case of intraoperative acute procedural failure.

Transapical off-pump mitral valve repair with NeoChord implantation: A systematic review

INTRODUCTION

Mitral valve repair (MVr) is the gold standard for the treatment of degenerative mitral valve regurgitation (MR). The recently introduced NeoChord DS1000 has gained increasing recognition as a feasible, potentially safe, and effective procedure with minor complications and promising outcomes. This study aims to conduct a systematic review of the published literature that discusses the technical feasibility and outcome of transapical off-pump MVr with NeoChord DS1000 device implantation in the treatment of degenerative MR.

METHODS

This review was performed according to the PRISMA statement. Databases searched in this review included Pubmed, Web of Science, Scopus, and Cochrane databases for systematic reviews. All English articles on humans reporting isolated MVr using NeoChord DS1000 device were included provided that basic preoperative data, operative specifications, and postoperative mortality and morbidity were reported.

RESULTS

This review included six studies comprised 249 patients who had NeoChord mitral procedure. Almost all patients included had severe MR (243/249, 97.6%). Operative success was achieved in 241 out of the 249 patients (96.8%). No intraoperative mortality was reported. Intraoperative arrhythmia was reported in six patients (2.4%) and significant bleeding was reported in eight patients (3.2%).

CONCLUSION

Awaiting more evidence, NeoChord mitral procedure appears to be a promising procedure that can be considered in selected cases.

Transapical off-pump echo-guided mitral valve repair with neochordae implantation mid-term outcomes

BACKGROUND

The NeoChord echo-guided transapical beating heart repair is a promising early-stage minimally invasive surgical procedure for degenerative mitral valve (MV) regurgitation (DMR) correction. The technique has been improved since its inception following procedure standardization, patient selection optimization, and learning curve stabilization. We hereby present the mid-term clinical results through three years of our large single center experience.

METHODS

All consecutive patients with severe symptomatic DMR due to prolapse or flail of one or both mitral leaflets that underwent the NeoChord procedure between November 2013 and June 2019 were included. Patients were categorized according to MV anatomy; Type A isolated central posterior leaflet prolapse and/or flail, Type B posterior multi-segment prolapse and/or flail, Type C anterior and/or bi-leaflet prolapse or flail, Type D paracommissural prolapse and/or flail and/or significant leaflet and/or annular calcifications. Patients underwent clinical and echocardiographic follow-up at one, three, six, twelve months and yearly thereafter. Clinical outcomes and the composite primary endpoint (patient success) were defined according to Mitral Valve Academic Research Consortium (MVARC) criteria. Mitral regurgitation (MR) severity was graded as absent, mild, moderate and severe according to American Society of Echocardiography (ASE) and European Society of Cardiology (ESC) guidelines.

RESULTS

Two hundred and three patients were included; median follow-up was 24 months [interquartile range (IQR), 9-36]. Median age was 64 years (IQR, 54-74 years), median Society of Thoracic Surgeons (STS) Predicted Risk of Mortality (PROM) was 0.60% (IQR, 0.32-1.44%). There were 106 Type A patients (52.2%), 68 Type B (33.5%), 16 Type C (7.9%), and 13 Type D (6.4%). Kaplan-Meier estimate of survival was 99.0%±0.7% at one and two years and 94.0%±2.9% at three years. At one-year follow-up patient success was 91.2%±2.0% and 111 patients (74%) presented a residual MR mild or less (1+). At three-year follow-up patient success was 81.2%±3.8% and 32 patients (64%) had a residual MR mild or less (1+). Patient success was significantly different according to anatomical type (P=0.001). Echocardiographic analysis showed a significant acute left ventricle and left atrial reverse remodeling that was maintained up to three years.

CONCLUSIONS

The NeoChord echo-guided transapical beating heart repair procedure demonstrated good clinical outcomes and echocardiographic results up to three-year follow-up.

Combining echocardiographic and anatomic variables to predict outcomes of mitral valve repair with the NeoChord procedure

BACKGROUND

Trans-apical, echo-guided NeoChord mitral valve (MV) repair is an innovative procedure to treat degenerative mitral regurgitation (MR) without concomitant annuloplasty. Recently, leaflet-to-annulus index (LAI) has been identified as a positive prognostic predictor of outcomes at 1-year follow up. The aim of this study is to develop a pre-operative predictor tool to assess probability of success with NeoChord procedure utilizing multi-factor echocardiographic and anatomic variables.

METHODS

We included ninety-one consecutive patients with prolapse/flail of the posterior mitral leaflet, who subsequently underwent NeoChord MV repair between November 2013 and October 2016. All patients completed post-operative echocardiographic follow-up assessments for up to 2 years. A random forest regression algorithm identified and ranked the most relevant predictors of moderate-severe MR. A multi-variable Cox regression model was performed at follow-up intervals, to assess variables associated with residual MR that was classified as mild or less. Bootstrapping re-samples were used to validate an estimated survival model. Predictive accuracy was assessed using a discrimination index that corrected for over-optimism.

RESULTS

We developed a nomogram which used the results of a multi-variable model to predict the probability of mild or less residual MR at follow-up periods (discharge, 1, 3, 6 months, 1 and 2 years). Identified predictors included LAI, systolic pulmonary artery pressure, indexed left ventricle end-systolic volume (iLVESV), prolapse/flail width (FW), systolic antero-posterior (AP) annulus diameter, systolic latero-lateral (LL) annulus diameter and presence of calcification.

CONCLUSIONS

A NeoChord MV repair prediction tool would be helpful in clinical decision-making and in the identification of patients who may benefit from a ringless mitral valve repair using the NeoChord procedure.

Transcatheter Mitral Valve Chordal Repair: Current Indications and Future Perspectives

Transcatheter Mitral Valve Repair (TMVRe) technologies constitute a rapidly expanding field, and have the potential of being adopted as a valuable alternative to surgery in selected patients. TMVRe devices can be distinguished depending on the targeted part of the Mitral Valve (MV) apparatus. Standard classification includes leaflet repair, direct/indirect annuloplasty, chordal repair, and ventricular/chamber remodeling devices. We present the current device situation on chordal repair technologies. Nowadays, transapical off-pump beating heart chordal implantation procedure has become a safe and reproducible option for Degenerative Mitral Regurgitation (DMR). Besides the truly minimally-invasiveness of the procedure, another unique advantage offered by a beating-heart chordal implantation is the real-time assessment of chordal length adjustment during heart cycle with a normally filled left ventricle. Currently, one system is commercially available in Europe, the NeoChord DS 1000 (NeoChord, Inc., St. Louis Park, MN) and the Harpoon TDS-5 (Edwards Lifesciences, Irvine, CA) should become available soon. There is also a diffuse and strong interest to move from a transapical procedure toward a fully transcatheter (transfemoral and transeptal) procedure as shown by the increased number of preclinical programs under development. Interestingly, to achieve outcomes that equate to those of open surgery in DMR, transcatheter therapies will need to follow rigid indications due to strict patient selection criteria for each device, or adopt multiple techniques in a single repair procedure for complex MV disease. Continuous analysis of current clinical results together with future dedicated trial will be of extreme importance to foster the new and upcoming field of transcatheter MV therapy technology development.