Safety and performance of a novel transventricular beating heart mitral valve repair system: 1-year outcomes

Transcatheter Mitral Valve Intervention: Current and Future Role of Multimodality Imaging for Device Selection and Periprocedural Guidance

Mitral regurgitation (MR) is a broadly diffuse valvular heart disease (VHD) with a significant impact on the healthcare system and patient prognosis. Transcatheter mitral valve interventions (TMVI) are now well-established techniques included in the therapeutic armamentarium for managing patients with mitral regurgitation, either primary or functional MR. Even if the guidelines give indications regarding the correct management of this VHD, the wide heterogeneity of patients' clinical backgrounds and valvular and heart anatomies make each patient a unique case, in which the appropriate device's selection requires a multimodal imaging evaluation and a multidisciplinary discussion. Proper pre-procedural evaluation plays a pivotal role in judging the feasibility of TMVI, while a cooperative work between imagers and interventionalist is also crucial for procedural success. This manuscript aims to provide an exhaustive overview of the main parameters that need to be evaluated for appropriate device selection, pre-procedural planning, intra-procedural guidance and post-operative assessment in the setting of TMVI. In addition, it tries to give some insights about future perspectives for structural cardiovascular imaging.

Minimally Invasive Mitral Valve Repair Using Transcatheter Chordal Attachments

The advent of transcatheter mitral chordal replacement techniques has offered an alternative approach that is less invasive and may be more suitable for select patients compared with surgical repair. These systems involve introducing artificial chordae, via catheter, to replace or supplement damaged or elongated natural chordae. These artificial chordae are anchored at one end to the mitral leaflet and the other end to the papillary muscle or directly to the left ventricular apex, restoring the leaflet's coaptation and reducing regurgitation. Early trials and studies suggest promising results in terms of safety and efficacy in reducing MR severity and improving symptoms.

Evaluation of a Novel Automated Suturing Technology for Mitral Chordal Implantation: 1-Year Results

PURPOSE

A new automated expanded polytetrafluoroethylene (ePTFE) suture placement device and a new customized titanium fastener deployment device were clinically evaluated in open and less-invasive mitral valve repair (MVr).

DESCRIPTION

Twelve patients were monitored for 1 year after undergoing MVr using the study devices. The study end points included surgical outcomes, operative times, valve repair durability, adverse events, and mortality.

EVALUATION

Three patients received 1 ePTFE chord using the study technology, and 9 patients received 2 chords. Mitral regurgitation at 30 days was absent in 8 patients, trace in 2, and mild in 2. At the 1-year follow-up, mitral regurgitation was absent in 7 patients, trace in 2, mild in 2, and moderate in 1. There were no replacement chord failures, reoperations, or death.

CONCLUSIONS

The initial outcomes of new automated ePTFE suture placement and titanium fastener deployment devices encourage further clinical evaluations.

Feasibility Study of a Novel Transapical Chordal Implantation System in a Porcine Model

Transapical beating-heart mitral repair with chordal implantation system has been considered as an alternative treatment for degenerative mitral regurgitation. This study aimed to assess the feasibility and safety of the E-Chord system (Med-Zenith Medical, Beijing, China) for transapical beating-heart mitral valve repair in a porcine model. Artificial chordae were transapically implanted on the mitral valves of 12 anesthetized pigs under epicardial echocardiographic guidance and secured outside the left ventricular apex. The study endpoints included procedural success, device durability, and tissue response to the device. The procedural success rate was 100% (12/12). All animals were implanted with E-Chord in the anterior and posterior leaflets, respectively, and survived uneventfully until euthanized as planned. During the 180-day follow-up, no animal had significant mitral valve dysfunction. The gross observation showed no evidence of anchor detachment and chordal rupture, and there was no obvious damage or changes to mitral leaflets. Microscopic evaluation revealed that the endothelialization of anchor and chordae was completed 90 days after implantation and there was no evidence of chordal rupture, thrombosis, or infection during the 180-day follow-up. The E-Chord system was found to be feasible and safe for heart-beating mitral chordal implantation in a porcine model. The findings of this study suggest that the E-Chord system may be a potential alternative for the treatment of degenerative mitral regurgitation in humans.

Degenerative mitral regurgitation

Degenerative mitral regurgitation is a major threat to public health and affects at least 24 million people worldwide, with an estimated 0.88 million disability-adjusted life years and 34,000 deaths in 2019. Improving access to diagnostic testing and to timely curative therapies such as surgical mitral valve repair will improve the outcomes of many individuals. Imaging such as echocardiography and cardiac magnetic resonance allow accurate diagnosis and have provided new insights for a better definition of the most appropriate timing for intervention. Advances in surgical techniques allow minimally invasive treatment with durable results that last for ≥20 years. Transcatheter therapies can provide good results in select patients who are considered high risk for surgery and have a suitable anatomy; the durability of such repairs is up to 5 years. Translational science has provided new knowledge on the pathophysiology of degenerative mitral regurgitation and may pave the road to the development of medical therapies that could be used to halt the progression of the disease.

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.

A review of the development of interventional devices for mitral valve repair with the implantation of artificial chords

Mitral regurgitation (MR) was the most common heart valve disease. Surgical repair with artificial chordal replacement had become one of the standard treatments for mitral regurgitation. Expanded polytetrafluoroethylene (ePTFE) was currently the most commonly used artificial chordae material due to its unique physicochemical and biocompatible properties. Interventional artificial chordal implantation techniques had emerged as an alternative treatment option for physicians and patients in treating mitral regurgitation. Using either a transapical or a transcatheter approach with interventional devices, a chordal replacement could be performed transcatheter in the beating heart without cardiopulmonary bypass, and the acute effect on the resolution of mitral regurgitation could be monitored in real-time by transesophageal echo imaging during the procedure. Despite the in vitro durability of the expanded polytetrafluoroethylene material, artificial chordal rupture occasionally occurred. In this article, we reviewed the development and therapeutic results of interventional devices for chordal implantation and discuss the possible clinical factors responsible for the rupture of the artificial chordal material.

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.

Outcomes of transapical mitral valve repair with neochordae implantation

OBJECTIVE

Transapical off-pump beating-heart neochord implantation (NC) has shown encouraging early results in patients with degenerative mitral regurgitation. The aim of this study was to evaluate clinical and echocardiographic 5-year outcomes of patients who underwent NC.

METHODS

All patients who underwent NC at our institution from November 2013 to March 2016 were included. Indications were severe symptomatic degenerative mitral regurgitation due to leaflet prolapse/flail. Patients were classified as having favorable anatomy (FA) and unfavorable anatomy (UA) on the basis of the extent and severity of mitral valve disease. All patients underwent clinical and echocardiographic follow-up at 1, 3, 6, and 12 months, and annually thereafter. Data were prospectively collected and retrospectively analyzed. Outcomes were on the basis of the Mitral Valve Academic Research Consortium guidelines.

RESULTS

One hundred consecutive patients were included in the analysis (FA: 81%; UA: 19%). Median age was 66 years (interquartile range, 58-76) and median European System for Cardiac Operative Risk Evaluation (EuroSCORE) II was 1.4% (interquartile range, 0.7-2.3). Technical and procedural success were 98% and 94%, respectively. Thirty-day mortality was 2%. Device success was 94%, 92%, and 78%, at 30 days, 1-year, and 5 years, respectively. Patient success at 1 year was 92%. Median follow-up was 5.1 years. At 5 years, overall survival was 83% with no difference between FA and UA patients. Cumulative incidence of severe mitral regurgitation recurrence at 5 years was 14% (95% CI, 6.5%-22.8%) in FA patients and 63% (95% CI, 39.7%-86.2%) in UA patients, respectively (P < .001). Patients with FA compared with UA had a lower incidence of reintervention (14.7% vs 43.4%; P < .001).

CONCLUSIONS

Transapical off-pump beating heart NC might represent an acceptable option in patients with degenerative mitral valve disease and FA.

A journey from resect to respect to restore: aiming at optimal physiological surgical mitral valve repair

The concept of 'repairing' a degenerated mitral valve in order to restore the native competence means achieving the best physiological result coupled with the least invasive approach: this represents an interesting challenge for cardiac surgeons. The evolution of cardiac surgery through the years has involved techniques and technologies in every field of interest. From 'resect', to 'respect', to 'restore': the micro-invasive approach based on Neochord implant implies a transapical beating heart surgery which is based on the concept of implanting artificial chordae, preserving the physiological dynamics of the mitral annulus and avoiding the disadvantages of cardiopulmonary bypass and cardioplegic arrest of the heart.

Transapical mitral valve repair procedures: Primetime for microinvasive mitral valve surgery

INTRODUCTION

Nowadays micro-invasive-procedures (off-pump, beating-heart) for mitral valve repair (MVRe) are abruptly expanding with the potential to be adopted as a valuable alternative to surgery. In the present manuscript, the authors review the available technologies intended to treat mitral regurgitation (MR) through transapical approach, including annuloplasty and chordal-repair options.

ANNULOPLASTY

To date, Valcare Amend is the only transapical MV ring to have been implanted in patients. The device allows for stabilization of the annulus through a complete semirigid d-shaped ring. The first-in-human successful procedure was performed in 2016 by our Group and subsequent clinical experience included a total of 14 implanted patients. Currently, the technology is under clinical trial evaluation to validate the efficacy and safety profile of the device.

CHORDAL REPAIR

Beating-heart chordal implantation via transapical approach is a current feasible, safe and reproducible option. Neochord DS1000 is the most widely used technology in the field, with a solid procedural experience and good results in well-selected patients. Its clinical use has been validated in Europe since 2012, while it is still under clinical investigation in the United States. Harpoon MVRe system is a novel technology, recently CE-mark approved for clinical use.

DISCUSSION AND CONCLUSIONS

Transapical micro-invasive technologies are current viable therapies to treat MR in selected patients. Although there are still several limitations that preclude an extensive use of such procedures, their results are promising in well-selected patients. Embracing transcatheter MVRe therapies should guide the cardiac surgeon through the new revolution of micro-invasive MV tailored repair.

Acute Ischaemic Mitral Valve Regurgitation

Acute ischaemic mitral regurgitation (IMR) is an increasingly rare and challenging complication following acute myocardial infarction. Despite recent technical advances in both surgical and percutaneous interventions, a poor prognosis is often associated with this challenging patient cohort. In this review, we revisit the diagnosis and typical echocardiographic features, and evaluate current surgical and percutaneous treatment options for patients with acute IMR.

Transcatheter Treatment of Mitral Regurgitation

Mitral valve disease, and in particular mitral regurgitation, is a common clinical entity. Until recently, surgical repair and replacement were the only therapeutic options available, leaving many patients untreated mostly due to excessive surgical risk. Over the last number of years, huge strides have been made regarding percutaneous, catheter-based solutions for mitral valve disease. Transcatheter repair procedures have most commonly been used, and in recent years there has been exponential growth in the number of devices available for transcatheter mitral valve replacement. Furthermore, the evolution of these devices has resulted in both smaller delivery systems and a shift towards transeptal access, negating the need for surgical incisions. In line with these advancements, and clinical trials demonstrating promising outcomes in carefully selected cases, recent guidelines have strengthened their recommendations for these devices. It is appropriate, therefore, to now review the current transcatheter repair and replacement devices available and the evidence for their use.

State-of-the-Art Review: Technical and Imaging Considerations in Novel Transapical and Port-Access Mitral Valve Chordal Repair for Degenerative Mitral Regurgitation

Degenerative mitral regurgitation (DMR) based on posterior leaflet prolapse is the most frequent type of organic mitral valve disease and has proven to be durably repairable in most cases by chordal repair techniques either by conventional median sternotomy or by less invasive approaches both utilizing extracorporeal circulation and cardioplegic myocardial arrest. Recently, several novel transapical chordal repair techniques specifically targeting the posterior leaflet have been developed as a far less invasive and beating heart (off-pump) alternative to port-access mitral repair. In order to perform a safe and effective minimally invasive mitral chordal repair, thorough knowledge of the anatomy of the mitral valve apparatus and adequate use of multimodality imaging both pre- and intraoperatively are fundamental. In addition, comprehensive understanding of the available novel devices, their delivery systems and the individual procedural steps are required.

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.

Devices for transcatheter mitral valve repair: current technology and a glimpse into the future

Introduction: Due to a large unmet need for the treatment of mitral regurgitation, transcatheter mitral valve repair devices have emerged in the last decade as an alternative therapeutic option. Given the complexity of this disease, several device systems for transcatheter mitral valve repair have been developed and are categorized according to its mechanism of action; each device has advantages and disadvantages for certain clinical and pathophysiologic characteristics, and in order to improve outcomes, proper patient selection among other key points are fundamental.Areas covered: The purpose of this article is to review the current state-of-the-art technologies available for transcatheter mitral valve repair, patient suitability, outcomes, and future perspectives.Expert opinion: Transcatheter therapy for mitral regurgitation improves outcomes and pushes the boundaries of biomedical technology while maintaining scientific rigor for device development. Surgical and percutaneous procedures should be viewed as complements to treat a wider spectrum of patients affected by this entity. Future directions from multidisciplinary innovation and cooperation will consolidate this therapeutic option.

Transcatheter mitral valve repair: an overview of current and future devices

The field of transcatheter mitral valve repair (TMVr) for mitral regurgitation (MR) is rapidly evolving. Besides the well-established transcatheter mitral edge-to-edge repair approach, there is also growing evidence for therapeutic strategies targeting the mitral annulus and mitral valve chordae. A patient-tailored approach, careful patient selection and an experienced interventional team is crucial in order to optimise procedural and clinical outcomes. With further data from ongoing clinical trials to be expected, consensus in the Heart Team is needed to address these complexities and determine the most appropriate TMVr therapy, either single or combined, for patients with severe MR.

Mitral valve surgery: current status and future prospects of the minimally invasive approach

Introduction: During the past five years the approach to procedural planning, operative techniques and perfusion strategies for minimally invasive mitral valve surgery (MIMVS) has evolved. With the goal to provide a maximum of patient safety the procedure has been modified according to individual patient characteristics and is largely based on preoperative imaging.Areas covered: In this review article we describe the important factors in image based therapy planning and simulation, different access strategies, the operative key-steps, a rationale use of devices, and highlight a few future developments in the field of MIMVS. Published studies were identified through pearl growing, citation chasing, a search of PubMed using the systematic review methods filter, and the authors' topic knowledge.Expert opinion: With the help of expert teams including surgeons specialized in mitral repair, anesthesiologists and perfusionists a broad spectrum of mitral valve pathologies and related pathologies can be treated with excellent functional outcomes. Avoiding procedure related complications is the key for success for any MIMVS program.

Transcatheter Repair of the Mitral Valve: Relevant Pathophysiology, Investigation, and Management

Mitral regurgitation (MR) is a common condition causing significant morbidity and mortality in the Western world. Although surgical therapy has developed over 5 decades to provide solutions, only a minority of patients undergo surgery. The last decade has seen the emergence and application of multiple transcatheter techniques in attempts to address this undertreated population with the large clinical experience of MitraClip providing the most insight. Clear understanding of the pathophysiology of different MR types as well as the role of particularly secondary MR on patient's clinical syndrome allow for better prediction as to which patient subgroups will benefit from different repair techniques or intervention at all. Most of the techniques are based on surgical technique and are applied as single-device/technique solutions, whether leaflet, chordal, or annular solutions, but with broadening experience, combination therapies are likely to find a place in creating a more complete and surgical-like solution.

Artificial papillary muscle device for off-pump transapical mitral valve repair

OBJECTIVE

New transapical minimally invasive artificial chordae implantation devices are a promising alternative to traditional open-heart repair, with the potential for decreased postoperative morbidity and reduced recovery time. However, these devices can place increased stress on the artificial chordae. We designed an artificial papillary muscle to alleviate artificial chordae stresses and thus increase repair durability.

METHODS

The artificial papillary muscle device is a narrow elastic column with an inner core that can be implanted during the minimally invasive transapical procedure via the same ventricular incision site. The device was 3-dimensionally printed in biocompatible silicone for this study. To test efficacy, porcine mitral valves (n = 6) were mounted in a heart simulator, and isolated regurgitation was induced. Each valve was repaired with a polytetrafluoroethylene suture with apical anchoring followed by artificial papillary muscle anchoring. In each case, a high-resolution Fiber Bragg Grating sensor recorded forces on the suture.

RESULTS

Hemodynamic data confirmed that both repairs-with and without the artificial papillary muscle device-were successful in eliminating mitral regurgitation. Both the peak artificial chordae force and the rate of change of force at the onset of systole were significantly lower with the device compared with apical anchoring without the device (P < .001 and P < .001, respectively).

CONCLUSIONS

Our novel artificial papillary muscle could integrate with minimally invasive repairs to shorten the artificial chordae and behave as an elastic damper, thus reducing sharp increases in force. With our device, we have the potential to improve the durability of off-pump transapical mitral valve repair procedures.