Percutaneous Septal Sinus Shortening

Two-year outcomes from the MitrAl ValvE RepaIr Clinical (MAVERIC) trial: a novel percutaneous treatment of functional mitral regurgitation

AIMS

We report the 2-year outcomes of the MitrAl ValvE RepaIr Clinical (MAVERIC) trial. Functional mitral regurgitation (FMR) is associated with poor outcomes for which there remains an unmet clinical need. ARTO is a transcatheter annular reduction device for the treatment of FMR and an emerging alternative for patients at high surgical risk. The MAVERIC trial was designed to evaluate the safety and performance of the ARTO system in FMR and heart failure (HF).

METHODS AND RESULTS

MAVERIC is an international multicentre, prospective, single arm study enrolling patients with FMR grade ≥ 2, New York Heart Association (NYHA) class ≥II symptoms despite maximal medical therapy. Patients were excluded if they had significant structural mitral valve abnormality or life expectancy <1 year. The primary outcome measures were a composite safety outcome and efficacy defined as mitral regurgitation (MR) reduction 30 days post-procedure. Secondary outcome measures included safety, change in MR grade, NYHA class and hospitalization for HF at 2 years. Forty-five patients were enrolled. The composite safety outcome was met (2/45 adverse events at 30 days) and no device-related deaths occurred at 2-year follow-up. A sustained reduction in MR [grade < 2: 21/31 (68%) vs. 31/31(0%); P < 0.0001], left ventricular end-diastolic volume index (90.0 ± 30 vs. 106 ± 26 mL/m² ; P = 0.004) and anteroposterior diameter (35.5 ± 4.7 vs. 41.4 ± 4.6 mm; P < 0.0001) was seen at 2 years compared to baseline. Progressive symptomatic improvement [NYHA class ≤II: 27/34 (80%) vs. 12/34 (36%); P < 0.0001] and a reduction in HF hospitalizations (19.8% 2 years post vs. 52.3% 2 years prior; P < 0.001) were seen at 2 years compared to baseline.

CONCLUSIONS

The ARTO system is a safe and effective treatment for FMR with reductions in left ventricular end-diastolic volumes sustained to 2 years.

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 and Replacement: What's on the Horizon?

There are more than 4 million people affected by mitral regurgitation in both the United States and Europe. Prior to the last decade the only options for treatment of MR were medical therapy and open-heart surgery which left many high risk patients with little option once medically optimized. However, we saw a flood in innovative transcatheter mitral valve interventions. As the technologies are refined these new approaches are considerably less invasive and for some high-risk patients may represent a superior option to conventional open-heart surgery. There are 3 main approaches currently being considered for transcatheter mitral valve repair, edge to edge repair, indirect annuloplasty and direct annuloplasty. There have also been large advancements in recent years in transcatheter replacement of the mitral valve. Although many of these devices are under investigation still, we sought to examine the current state of innovative transcatheter mitral valve technologies.

The first two cases of transcatheter mitral valve repair with ARTO system in Asia

BACKGROUND

MAVERIC (Mitral Valve Repair Clinical Trial) validates the safety and efficacy of the ARTO system. We here report the first two successful cases of utilizing the ARTO system in patients with symptomatic heart failure (HF) with functional mitral regurgitation (FMR) in Asia.

METHODS

Two patients, aged 70 and 63, had severe HF with FMR. Transesophageal echocardiography confirmed that the left ventricular ejection fractions were less than 50% with severe mitral regurgitation (MR) in both patients. Optimizing drug treatment could not mitigate their symptoms. Therefore, we used the ARTO system to repair the mitral valve for these patients on March 5 and 6, 2019, respectively.

RESULTS

Mitral valve repairs using the ARTO system were successfully performed under general anaesthesia for these two patients. MR was decreased immediately after the procedures in both patients. The 30-day and 3-month transthoracic echocardiography (TTE) revealed a moderate to severe MR in both patients, and the New York Heart Association (NYHA) scales were also partially improved.

CONCLUSION

The first two cases in Asia indicate that the ARTO system is feasible for patients with heart failure with FMR, and the patient selection appears to be crucial.

Future Technology

Mitral regurgitation is the most common valvular disease and significant (moderate/severe) mitral regurgitation is found in 2.3% of the population older than 65 years. New transcatheter minimally invasive technologies are being developed to address mitral valve disease in patients deemed too high a risk for conventional open-heart surgery. There are several features of the mitral valve (saddle-shaped noncalcified annulus with irregular leaflet geometry) that make a transcatheter approach to repair or replacing the valve more challenging compared with the aortic valve. Several devices are under investigation for transcatheter mitral valve replacement, and also for mitral valve repair targeting the mitral valve leaflets, chordae tendinae, and mitral annulus. The MitraClip device is the only Food and Drug Administration-approved device to treat mitral regurgitation by targeting the mitral leaflets. There are eight minimally invasive devices being studied in humans that target the mitral annulus, and at least two devices being studied in animal models. There are 5 devices in clinical trials for minimally invasive approaches targeting the chordae tendinae. More than 10 different transcatheter mitral valves are in various stages of development and clinical trials. These transcatheter mitral valves can be delivered either through a transseptal, transapical, transaortic, or left atriotomy approach. It seems likely that transcatheter treatment approaches to mitral valve disease will become more common, at least in the sick and elderly patient population.

Coronary Sinus-Based Approach to Mitral Regurgitation

Functional, or secondary, mitral regurgitation (FMR) is clinically important because patient with congestive heart failure with FMR have worse clinical outcomes and associated higher risks than patients without FMR. There is interest in finding repair techniques which may modify the mitral valve dysfunction and reduce the clinical impact. Although several devices have taken advantage of the close anatomical relationship between the coronary sinus and the posterior annulus of the mitral valve, in order to provide a cinching force on the mitral annulus, only the Carillon device is currently in use in humans. A double blind randomized trial is currently being done to evaluate the value of this therapy, building upon the favorable result of three prior safety and efficacy trials, which have led to European approval of the device.

The use of imaging in new transcatheter interventions: an EACVI review paper

Transcatheter therapies for the treatment of valve heart diseases have expanded dramatically over the last years. The new developments and improvements in devices and techniques, along with the increasing expertise of operators, have turned the catheter-based approaches for valvular disease into an established treatment option. Various imaging techniques are used during these procedures, but echocardiography plays an essential role during patient selection, intra-procedural monitoring, and post-procedure follow-up. The echocardiographic assessment of patients undergoing transcatheter interventions places demands on echocardiographers that differ from those of the routine evaluation of patients with valve disease, and there is a need for specific expertise for those working in the cath lab. In the context of the current rapid developments and growing use of transcatheter valve therapies, this document intends to update the previous recommendations and address new advancements in imaging, particularly for those involved in any stage of the treatment of patients with valvular heart diseases.

Future horizons for catheter-based interventions in adult congenital and structural heart disease

In recent decades, there has been an exponential growth in both the number and range of catheter-based interventions for adult congenital and structural heart disease. In this article, we discuss the rationale for the ongoing development of minimally invasive multidisciplinary interventions; the required training elements necessary to achieve expertise in the field; the cardiac team needed to best perform these interventions; and the currently available and up and coming technologies for performing transcatheter valve therapies.

Percutaneous Techniques for the Treatment of Patients with Functional Mitral Valve Regurgitation

Percutaneous approaches to mitral regurgitation remain largely investigational. In the last decade, novel percutaneous strategies have opened new options in the treatment of valvular heart disease. Several studies are currently underway to determine the benefits of transcatheter mitral valve repair therapy. Transcatheter chordal procedures are being developed, including chordal cutting and chordal implantation. Transcatheter valve implantation in the mitral position might offer a desirable alternative in selected patients and has been accomplished in a compassionate fashion on rare occasions in patients who are not candidates for surgical valve repair or replacement.

Is there a role for surgeons in transcatheter mitral valve procedures?

PURPOSE OF REVIEW

The rapid advancement in transcatheter therapies seeks to provide less invasive options compared with conventional surgery in the treatment of acquired valvular heart disease. A number of transcatheter mitral valve devices using a variety of approaches for the treatment of mitral regurgitation are under development or in early clinical application. Although yet to be clearly defined, there is no doubt that transcatheter mitral valve procedures will have a significant role alongside conventional surgery. The question is: will surgeons, who have led the treatment of mitral valve disease for the past 30 years, have a role in these procedures?

RECENT FINDINGS

In order to answer this question, this review discusses key understanding of mitral valve anatomy, function and disorder required to perform transcatheter mitral valve interventions. It assesses the potential role of transcatheter therapies with particular reference to percutaneous edge-to-edge repair using the Mitraclip system (Abbott Vascular Devices, California, USA). The new era in collaboration between surgeons and cardiologists is discussed and the potential role of the surgeon in percutaneous mitral valve procedures is examined.

SUMMARY

Transcatheter mitral valve procedures demand increasing collaboration between cardiologists and surgeons in order to achieve optimal outcomes. Interventional cardiologists will require dedicated training in the specialized field of transcatheter interventions in acquired structural heart diseases. As the delivery of such therapies brings the interface between interventional cardiology and cardiac surgery ever closer, there is the potential for a niche area in cardiac surgery to develop comprising minimally invasive surgical and transcatheter skills.

Investigational devices for mitral regurgitation: state of the art

The incidence of mitral regurgitation (MR) is rising as a result of an aging population worldwide. Surgical repair or replacement of the mitral valve remains the standard of care for patients with severe MR as the only approach to achieve sustained relief of symptoms or heart failure. However, the majority of patients with severe MR do not undergo surgery because of high perceived perioperative risk. Recently, there has been great enthusiasm in the pursuit of a less invasive percutaneous approach to the treatment of MR to avoid thoracotomy or cardiopulmonary bypass, even if less efficacious. This article reviews the latest developments of various percutaneous options in the treatment of MR.

Percutaneous approaches to mitral regurgitation

Percutaneous therapy for mitral repair has emerged over the past several years as an investigational option for treating mitral regurgitation (MR). A variety of novel methods to treat MR using a percutaneous route have been developed. Most of these approaches are modifications of surgical techniques, some established and some obscure. The basic surgical approaches to mitral repair are annuloplasty and leaflet repair. Catheter-based devices mimic or approximate these surgical approaches. MR as a disease process is heterogeneous, and different therapeutic approaches are needed for different etiologies of MR and morphologies of the mitral apparatus. Primary leaflet diseases are mitral prolapse and fibroelastic deficiency. Secondary, or functional, MR exists when the leaflets are normal. Functional ischemic MR and functional MR related to heart failure occur in different populations and historically have had different responses to surgical therapy. Leaflet repair using a percutaneous clip has been accomplished for patients with mitral valve prolapse and also some patients with functional MR. Indirect annuloplasty via the coronary sinus has shown promising early human trial results in patients with functional MR. Direct annuloplasty and left ventricular chamber remodeling technologies are in the earliest stages of human application. This group of approaches is being studied as an alternative to surgery for selected patients. The MitraClip (Evalve, Menlo Park, CA) for leaflet repair has been approved for use in Europe and is being applied predominantly to high-risk surgical patients with either functional or degenerative, organic MR. One of the coronary sinus devices has received approval in Europe as well. This complex clinical landscape has made device development, trial design, and patient selection complicated. Steady progress in the field is being made. Many patients with functional MR who are currently treated medically will be the subject of upcoming trials. Catheter methods for mitral repair promise to serve some patients currently considered high risk for surgery, and some patients may have catheter therapy as an alternative to surgery.

Mitral cerclage annuloplasty, a novel transcatheter treatment for secondary mitral valve regurgitation: initial results in swine

OBJECTIVES

We developed and tested a novel transcatheter circumferential annuloplasty technique to reduce mitral regurgitation in porcine ischemic cardiomyopathy.

BACKGROUND

Catheter-based annuloplasty for secondary mitral regurgitation exploits the proximity of the coronary sinus to the mitral annulus, but is limited by anatomic variants and coronary artery entrapment.

METHODS

The procedure, "cerclage annuloplasty," is guided by magnetic resonance imaging (MRI) roadmaps fused with live X-ray. A coronary sinus guidewire traverses a short segment of the basal septal myocardium to re-enter the right heart where it is exchanged for a suture. Tension is applied interactively during imaging and secured with a locking device.

RESULTS

We found 2 feasible suture pathways from the great cardiac vein across the interventricular septum to create cerclage. Right ventricular septal re-entry required shorter fluoroscopy times than right atrial re-entry, which entailed a longer intramyocardial traversal but did not cross the tricuspid valve. Graded tension progressively reduced septal-lateral annular diameter, but not end-systolic elastance or regional myocardial function. A simple arch-like device protected entrapped coronary arteries from compression even during supratherapeutic tension. Cerclage reduced mitral regurgitation fraction (from 22.8 +/- 12.7% to 7.2 +/- 4.4%, p = 0.04) by slice tracking velocity-encoded MRI. Flexible cerclage reduced annular size but preserved annular motion. Cerclage also displaced the posterior annulus toward the papillary muscles. Cerclage introduced reciprocal constraint to the left ventricular outflow tract and mitral annulus that enhanced leaflet coaptation. A sample of human coronary venograms and computed tomography angiograms suggested that most have suitable venous anatomy for cerclage.

CONCLUSIONS

Transcatheter mitral cerclage annuloplasty acutely reduces mitral regurgitation in porcine ischemic cardiomyopathy. Entrapped coronary arteries can be protected. MRI provided insight into the mechanism of cerclage action.

Percutaneous mitral annuloplasty

Mitral annuloplasty is the most common surgical procedure performed for mitral valve regurgitation, whether performed alone or as part of a more complex repair. A less invasive percutaneous approach to mitral annuloplasty associated with lesser morbidity might offer advantages over a surgical procedure in some patients, even if less efficacious. We review current experimental percutaneous approaches to mitral annuloplasty.

Long-term safety and durability of percutaneous septal sinus shortening (The PS(3) System) in an ovine model

OBJECTIVES

Chronic implants of the PS(3) system were conducted in an ovine model to assess durability and safety at up to 1 year follow-up.

BACKGROUND

The long-term durability and safety of emerging percutaneous devices for functional mitral regurgitation remain largely unknown.

METHODS

The PS(3) system (consisting of interatrial septal and great cardiac vein devices connected by an adjustable suture bridge) was placed in eight healthy adult sheep. The mitral annular septal-lateral dimension in systole (SLS) was acutely reduced by 15-20%. Animals were sacrificed at up to 12 months postimplant and characterized by intracardiac echocardiography, cardiac computed tomography (CT), and histopathology. In vivo forces exerted on the PS(3) bridge were measured by means of a novel load cell catheter.

RESULTS

At 3, 6, and 12 months after implantation, intracardiac echocardiographic and CT showed the PS(3) systems to be intact without erosion and with overall sustained reductions in the SLS. Histopathologic assessment revealed each component correctly deployed in its respective target site without evidence of erosion, thrombus, or device fracture. The SLS was 26.5 +/- 1.7 mm preimplant, 22.0 +/- 1.4 mm post-PS(3) (17.0% reduction), and 22.0 +/- 2.1 mm at latest follow-up. Mean forces exerted on the bridge in vivo ranged from 1.16 N to 1.87 N.

CONCLUSIONS

The PS(3) System demonstrated excellent biocompatibility without evidence of erosion, thrombosis, or perforation at up to one-year follow-up in this chronic healthy ovine model. Forces exerted in the PS(3) system were relatively modest and should contribute to the durability of the device.

Transcatheter Valve Repair and Replacement

There is significant interest in developing transcatheter therapy for valvular heart disease (VHD). Numerous devices have been developed for the percutaneous treatment of pulmonary and aortic stenosis as well as mitral regurgitation. Several of these devices have progressed to randomized clinical trials. These ongoing trials for aortic stenosis and mitral regurgitation will provide important insights into the durability of these therapies as well as the results following standard surgical repair. The field of transcatheter valve therapy is rapidly evolving, and this review aims to summarize the current status of the field.

Percutaneous and Minimally Invasive Valve Procedures

The incidence of valvular heart disease is expected to increase over the next several decades as a large proportion of the US demographic advances into the later decades of life. At the same time, the next several years can be anticipated to bring a broad transition of surgical therapy to minimally invasive (minithoracotomy and small port) access and the more gradual introduction of percutaneous approaches for the correction of valvular heart disease. Broad acceptance of these technologies will require careful and sometimes perplexing comparisons of the outcomes of these new technologies with existing standards of care. The validation of percutaneous techniques, in particular, will require the collaboration of cardiologists and cardiac surgeons in centers with excellent surgical and catheter experience and a commitment to trial participation. For the near term, percutaneous techniques will likely remain investigational and will be limited in use to patients considered to be high risk or to inoperable surgical candidates. Although current-generation devices and techniques require significant modification before widespread clinical use can be adopted, it must be expected that less invasive and even percutaneous valve therapies will likely have a major impact on the management of patients with valvular heart disease over the next several years.

[Ischemic mitral regurgitation: contributions of exercise echocardiography and new therapeutic perspectives]

The ischemic mitral regurgitation is defined by a left ventricular muscle disease affecting the function of normal mitral valve leaflets. This kind of mitral regurgitation is founded in about 20% of the ischemic cardiomyopathy and is attributed to the remodelling of the left ventricular shape. Its development is associated to a significantly worse prognosis. Frequently this ischemic mitral regurgitation will be associated to episode of acute heart failure decompensation. Its diagnosis is sometimes challenging as the degree of regurgitation might be extremely variable and affected by loading conditions. Echocardiography and especially exercise stress echocardiography has been demonstrated as an extremely powerful tool for its diagnosis and the prognostic evaluation. Its treatment should include the pharmacological treatment of the chonic heart failure and we are still waiting data in regard to the prognostic role of surgical mitral valvuloplastie. Works are still ongoing.

Safety and feasibility of acute percutaneous septal sinus shortening: First-in-human experience

BACKGROUND

Multiple percutaneous therapies for the treatment of functional and ischemic mitral regurgitation (FMR/IMR) are under development. We previously reported a novel percutaneous technique, the percutaneous septal sinus shortening [PS(3)] System which was effective in ameliorating FMR in an animal model. We herein report results from the first-in-human safety and feasibility pilot study involving the PS(3) System.

METHODS AND RESULTS

The primary objective of this first-in-human study was to evaluate the safety and feasibility of acute percutaneous septal-lateral shortening by using the PS(3) System in patients immediately prior to clinically-indicated surgical mitral valve repair. Two patients were enrolled. Patient One had severe aortic insufficiency with moderate functional mitral regurgitation. The PS(3) System reduced the MR grade from 2+ to 1+ with a decrease in the mean septal-lateral systolic (SLS) dimension from 38 to 27 mm (29% reduction). Patient Two had severe ischemic mitral regurgitation in the setting of severe multi-vessel disease and prior infero-posterior infarct. MR grade was reduced from 3+ to 1+ with a decrease in the mean SLS dimension from 36 to 25mm (31% reduction). There were no procedural complications and both patients proceeded to pre-planned cardiac surgery, where the devices were explanted under direct visualization.

CONCLUSIONS

The PS(3) System has been safely translated from the preclinical setting to first-in-human implantation. Both patients studied experienced a reduction in MR after device implantation, with significant SLS shortening. Further clinical trials will be needed to assess long-term efficacy and durability.

Percutaneous mitral valve annuloplasty for ischemic mitral regurgitation: First in man experience with a temporary implant

OBJECTIVE

This study evaluated human feasibility and acute efficacy of a novel percutaneous transvenous mitral annuloplasty (PTMA) device (Viacor) placed temporarily in the coronary sinus (CS): the implant allows in-situ incremental adjustment to optimally reduce the anterior-posterior mitral annulus (MA) dimension, and improve leaflet co-aptation and reducing mitral regurgitation (MR).

BACKGROUND

Surgical annuloplasty remains the standard treatment of severe ischemic MR but its application is limited by high morbidity and mortality. The effectiveness of PTMA device (Viacor) to reduce MR in the short-term has been demonstrated in animals studies but not in humans.

METHODS

Symptomatic patients with ischemic MR graded 2+ to 4+ requiring surgical mitral annuloplasty were screened. Patients with any mitral leaflet or mitral apparatus abnormality were excluded. Preoperatively, under general anesthesia and transesophageal echocardiography guidance, a temporary PTMA device was placed via the right internal jugular or subclavian vein.

RESULTS

Four patients were studied. After device placement and adjustment, regurgitant volume was substantially reduced (45.5 +/- 24.4 to 13.3 +/- 7.3 ml) via MA anterior-posterior diameter reduction (40.75 +/- 4.3 to 35.2 +/- 1.6 mm) in 3 patients. In one patient, the PTMA device could not be deployed due to extreme angulated anatomy.

CONCLUSIONS

PTMA in human is feasible and reduces ischemic MR (to grade 1+) by reducing MA anterior-posterior diameter. Temporary placement of the PTMA device may assist in the development of permanent implants and ensure optimal efficacy.

New techniques for percutaneous repair of the mitral valve

A variety of innovative techniques and devices are being developed for the percutaneous management of mitral insufficiency. More than 30 devices are in stages of development from early stage to human pivotal trials. Two devices for the management of degenerative myxomatous disease of the mitral valve replicate the Alfieri edge-to-edge surgical repair. One of those devices, the Evalve Mitraclip, is in a pivotal trial at the current time. The other devices address functional mitral regurgitation by a variety of techniques for performing mitral valve annuloplasty. The majority of devices take advantage of the proximity of the coronary sinus to the posterior mitral annulus to deliver devices that remodel the mitral annulus. Two devices perform septal lateral cinching decreasing the anterior posterior diameter of the mitral annulus and correcting leaflet malcoaptation. Numerous issues are discussed including regulatory hurdles and the integration of percutaneous techniques into clinical practice in a safe and efficacious manner.