Treatment of Chronic Functional Mitral Valve Regurgitation With a Percutaneous Annuloplasty System

Emerging Transcatheter Therapies for Valvular Heart Disease: Focus on Mitral and Tricuspid Valve Procedures

The emergence of percutaneous treatment options provides novel therapeutic alternatives for older and feeble patients who are at high risk for any surgical procedure. The purpose of our review was to offer an up-to-date analysis of the rapidly expanding field of percutaneous technologies for mitral, tricuspid, and pulmonary procedures. Edge-to-edge repair is an established treatment for secondary mitral regurgitation (MR), while transcatheter mitral valve replacement is a potential and expanding option for managing both secondary and primary MR. However, additional advancements are necessary to enhance the safety and feasibility of this procedure. Transcatheter tricuspid intervention is an emerging option that was conceived after the success of transcatheter procedures in aortic and mitral valves, and it is currently still in the early stages of advancement. This can be attributed, at least in part, to the previously overlooked effect of tricuspid regurgitation on patient outcomes. The development of edge-to-edge repair represents the forefront of innovations in transcatheter procedures. There is a scarcity of data about tricuspid annuloplasty and replacement, and further study is necessary. Transcatheter mitral, tricuspid, and pulmonary procedures show prospects for the future, while their role in clinical practice has not been definitively established.

Beyond Medical Therapy-An Update on Heart Failure Devices

Heart failure (HF) is a complex and progressive disease marked by substantial morbidity and mortality rates, frequent episodes of decompensation, and a reduced quality of life (QoL), with severe financial burden on healthcare systems. In recent years, several large-scale randomized clinical trials (RCTs) have widely expanded the therapeutic armamentarium, underlining additional benefits and the feasibility of rapid titration regimens. This notwithstanding, mortality is not declining, and hospitalizations are constantly increasing. It is widely acknowledged that even with guideline-directed medical therapy (GDMT) on board, HF patients have a prohibitive residual risk, which highlights the need for innovative treatment options. In this scenario, groundbreaking devices targeting valvular, structural, and autonomic abnormalities have become crucial tools in HF management. This has led to a full-fledged translational boost with several novel devices in development. Thus, the aim of this review is to provide an update on both approved and investigated devices.

Cardiac MRI-Enriched Phenomapping Classification and Differential Treatment Outcomes in Patients With Ischemic Cardiomyopathy

BACKGROUND

Significant controversy continues to confound patient selection and referral for revascularization and mitral valve intervention in patients with ischemic cardiomyopathy (ICM). Cardiac magnetic resonance (CMR) enables comprehensive phenotyping with gold-standard tissue characterization and volumetric/functional measures. Therefore, we sought to determine the impact of CMR-enriched phenomapping patients with ICM to identify differential outcomes following surgical revascularization and surgical mitral valve intervention (sMVi).

METHODS

Consecutive patients with ICM referred for CMR between 2002 and 2017 were evaluated. Latent class analysis was performed to identify phenotypes enriched by comprehensive CMR assessment. The primary end point was death, heart transplant, or left ventricular assist device implantation. A multivariable Cox survival model was developed to determine the association of phenogroups with overall survival. Subgroup analysis was performed to assess the presence of differential response to post-magnetic resonance imaging procedural interventions.

RESULTS

A total of 787 patients were evaluated (63.0±11.2 years, 24.8% women), with 464 primary events. Subsequent surgical revascularization and sMVi occurred in 380 (48.3%) and 157 (19.9%) patients, respectively. Latent class analysis identified 3 distinct clusters of patients, which demonstrated significant differences in overall outcome (P<0.001). Latent class analysis identified differential survival benefit of revascularization in patients as well as patients who underwent revascularization with sMVi, based on phenogroup classification, with phenogroup 3 deriving the most survival benefit from revascularization and revascularization with sMVi (hazard ratio, 0.61 [0.43-0.88]; P=0.0081).

CONCLUSIONS

CMR-enriched unsupervised phenomapping identified distinct phenogroups, which were associated with significant differential survival benefit following surgical revascularization and sMVi in patients with ICM. Phenomapping provides a novel approach for patient selection, which may enable personalized therapeutic decision-making for patients with ICM.

Cerebral embolic protection during transcatheter heart interventions

Stroke remains a devastating complication of transcatheter aortic valve replacement (TAVR), with the incidence of clinically apparent stroke seemingly fixed at around 3% despite TAVR's significant evolution during the past decade. Embolic showers of debris (calcium, atheroma, valve material, foreign material) are captured in the majority of patients who have TAVR using a filter-based cerebral embolic protection device (CEPD). Additionally, in systematic brain imaging studies, the majority of patients receiving TAVR exhibit new cerebral lesions. Mechanistic studies have shown reductions in the volume of new cerebral lesions using CEPDs, yet the first randomised trial powered for periprocedural stroke within 72 hours of a transfemoral TAVR failed to meet its primary endpoint of showing superiority of the SENTINEL CEPD. The present review summarises the clinicopathological rationale for the development of CEPDs, the evidence behind these devices to date and the emerging recognition of cerebral embolisation in many non-TAVR transcatheter procedures. Given the uniqueness of each of the various CEPDs under development, specific trials tailored to their designs will need to be undertaken to broaden the CEPD field, in addition to evaluating the role of CEPD in non-TAVR transcatheter heart interventions. Importantly, the cost-effectiveness of these devices will require assessment to broaden the adoption of CEPDs globally.

Structural Interventions in Heart Failure: Mending a Broken Heart

Advanced heart failure is often accompanied by perturbations in cardiac chamber or valve geometries which result in worsening cardiac function and hemodynamics. Once limited to surgical procedures, recent developments in minimally invasive percutaneous techniques have demonstrated efficacy in patients with both reduced and preserved ejection fraction who are at an elevated surgical risk for perioperative events. This review highlights a subset of the interventions available in clinical practice or in development for the treatment of these valvular and structural alterations.

Cardiac computed tomography based analysis of mitral annulus, coronary sinus and left circumflex artery in patients with mitral regurgitation: Implications for transcatheter mitral annuloplasty techniques

INTRODUCTION

CT imaging analysis of mitral annulus (MA), coronary sinus (CS) and left circumflex artery (LCX) is critical to transcatheter mitral annuloplasty (TMA), which, however, is scantly reported. We aimed to comprehensively assess MA, CS and LCX anatomy and geometry in mitral regurgitation (MR) based on 3-D reconstruction of cardiac CT images.

METHODS

Patients with primary or secondary MR and patients without MR were recruited and underwent cardiac CT examination. MR severity was evaluated by echocardiography. 3-D reconstruction of cardiac CT images was done by the Mimics Research 21.0 software. A MA-centered two dimensional coordinate system, a CS plane, a MA plane and a series of auxiliary planes along the posterior MA were created for the measurement of parameters defining MA, CS and LCX anatomy and geometry during the cardiac cycle.

RESULTS

The secondary MR group had a significantly higher MA perimeter index than the other two groups during the cardiac cycle. The CS diameters at most sites, and the posterior MA radian were substantially greater in the two MR groups. Distances between the CS and MA at some locations were significant different among the three groups. The secondary MR group had a significantly smaller CS-MA plane angle than the other two groups during systole, and than control group during diastole. The site where the CS crossed LCX was pinpointed.

CONCLUSION

The comprehensive information from this study may help improve the results of TMA and enhance the design of devices for a better annuloplasty effect.

Transcatheter Mitral Valve Repair or Replacement: Competitive or Complementary?

Over the last two decades, transcatheter devices have been developed to repair or replace diseased mitral valves (MV). Transcatheter mitral valve repair (TMVr) devices have been proven to be efficient and safe, but many anatomical structures are not compatible with these technologies. The most significant advantage of transcatheter mitral valve replacement (TMVR) over transcatheter repair is the greater and more reliable reduction in mitral regurgitation. However, there are also potential disadvantages. This review introduces the newest TMVr and TMVR devices and presents clinical trial data to identify current challenges and directions for future research.

Restructuring the Heart From Failure to Success: Role of Structural Interventions in the Realm of Heart Failure

Heart failure through the spectrum of reduced (HFrEF), mid-range (or mildly reduced or HFmEF), and preserved ejection fraction (HFpEF), continues to plague patients' quality of life through recurrent admissions and high mortality rates. Despite tremendous innovation in medical therapy, patients continue to experience refractory congestive symptoms due to adverse left ventricular remodeling, significant functional mitral regurgitation (FMR), and right-sided failure symptoms due to significant functional tricuspid regurgitation (FTR). As most of these patients are surgically challenging for open cardiac surgery, the past decade has seen the development and evolution of different percutaneous structural interventions targeted at improving FMR and FTR. There is renewed interest in the sphere of left ventricular restorative devices to effect reverse remodeling and thereby improve effective stroke volume and patient outcomes. For patients suffering from HFpEF, there is still a paucity of disease-modifying effective medical therapies, and these patients continue to have recurrent heart failure exacerbations due to impaired left ventricular relaxation and high filling pressures. Structural therapies involving the implantation of inter-atrial shunt devices to decrease left atrial pressure and the development of implantable devices in the pulmonary artery for real-time hemodynamic monitoring would help redefine treatment and outcomes for patients with HFpEF. Lastly, there is pre-clinical data supportive of soft robotic cardiac sleeves that serve to improve cardiac function, can assist contraction as well as relaxation of the heart, and have the potential to be customized for each patient. In this review, we focus on the role of structural interventions in heart failure as it stands in current clinical practice, evaluate the evidence amassed so far, and review promising structural therapies that may transform the future of heart failure management.

Transcatheter mitral valve intervention

Mitral regurgitation is a common valvular heart disorder increasing with age. Many patients are ineligible for mitral valve surgery due to their age and other comorbidities. Left untreated, patients develop severe disease with a poor prognosis. The development of lower risk percutaneous mitral valve interventions has helped meet the needs of this previously untreated patient group. This review explores the recent and more established developments that have expanded the armamentarium for transcatheter mitral valve intervention.

Current devices and interventions in mitral regurgitation

Mitral regurgitation (MR) is the most common valvular disease. With a rising incidence in older age, the prevalence of relevant comorbidities inevitably increases. Considering the constantly aging population with high surgical risk, transcatheter therapy of MR is gaining increasing importance. Interventional therapy of either primary or secondary MR represents an alternative to pure drug or surgical therapy. With mitral valve transcatheter edge-to-edge repair, a well-established treatment has evolved in the past two decades. In addition, direct or indirect annuloplasty and ultimately transcatheter mitral valve implantation further expand the armamentarium. The current broad spectrum of interventional therapy options allows for patient-oriented therapy individually targeting different MR pathologies. This review discusses the current landscape of transcatheter therapies for relevant MR.

Transcatheter Repair and Replacement Technologies for Mitral Regurgitation: a European Perspective

Purpose of Review

We aimed to picture the contemporary landscape of available catheter-based repair and replacement solutions for mitral regurgitation (MR) in Europe.

Recent Findings

Edge-to-edge repair remains the dominant technique for transcatheter mitral valve repair especially in the context of secondary mitral regurgitation. Two recent randomized trials reported seemingly contradicting clinical results with transcatheter edge-to-edge repair for patients with heart failure and severe secondary MR. A proportionality framework related to secondary MR was proposed to help explain inconsistencies but requires further research. (In)Direct annuloplasty primarily aims to correct secondary MR; however, the scientific basis seems less robust. One dedicated transcatheter heart valve has the CE mark for mitral valve replacement but requires transapical access. Balloon-expandable transcatheter aortic valve platforms are emerging for transvenous transseptal mitral replacement in the context of mitral annular calcification, a failing surgical mitral bioprosthesis, or annuloplasty. Advanced computed tomography imaging techniques improved pre-procedural planning and introduced the option for modeling and simulation.

Summary

Development of a toolbox of catheter-based technologies, complementary imaging modalities, and refined patient selection offer novel perspectives to high-risk patients with primary or secondary MR. Clinical trials are required to help formulate evidence-based guidelines for the management of mitral valve disease.

Guide to functional mitral regurgitation: a contemporary review

Functional mitral regurgitation (FMR) occurs in the absence of organic mitral valve (MV) disease and is a result of LV dysfunction due to ischemic vs. non ischemic etiologies. The prevalence of FMR is increasing, as 2.0-2.5 million people in the USA were diagnosed with FMR in 2000-and this number is expected to double to 4 million by 2030. FMR tends to develop in a significant number of patients after myocardial infarction (MI) and many develop heart failure (HF) subsequently with mortality rates ranging from 15-40% at 1 year. Therefore, there has been much interest and effort to develop optimized methods for quantifying and classifying the severity of FMR, as well as developing effective therapeutic interventions to improve outcomes in patients with significant FMR. Echocardiogram is typically the primary diagnostic method of assessment, however, there have been various technological advances including cardiac CT and cardiac MRI that can better guide quantification and management of this disease. Management of this disease is mostly aimed at optimizing left ventricular (LV) remodeling with surgical and transcatheter management gaining more popularity with recent times. The purpose of this paper is to provide a comprehensive review of the current evaluation methods and interventional strategies for FMR.

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.

Over 15 years: the advancement of transcatheter mitral valve repair

Patients with severe symptomatic mitral regurgitation, if left untreated, have a poor prognosis. In those patients not eligible for mitral valve (MV) surgery, percutaneous repair may improve clinical outcomes. In the past 15 years several devices have been developed to address different MV lesions. This manuscript will review the advancement of transcatheter MV repair through the years, focusing on technologies for which consistent clinical data is available.

The unfinished saga of invasive procedures for secondary mitral regurgitation

Secondary mitral regurgitation (MR) is a common valvular heart disease. Its prognostic burden in patients suffering from idiopathic or ischemic cardiomyopathy (ICM) with left ventricular (LV) dysfunction/dilation has been clearly demonstrated. Severe secondary MR is associated with an increased mortality and frequent heart failure hospitalizations. Although guideline-directed medical therapy (GDMT) is the cornerstone of the management of secondary MR, a certain proportion of patients remain symptomatic. For these patients, several surgical techniques have been progressively developed during the last few decades (replacement, repair, sub-valvular apparatus interventions and other ventricular approaches). In the absence of evidence-based medicine, the benefits of these surgical procedures remains controversial, leading to a low level of recommendation in the guidelines. One way to anticipate the future is to look to the past. Recent prospective randomized trials evaluated surgical and percutaneous techniques and led to a better understanding of how best to treat this disease. In this article, we aim to describe the saga of the surgical and percutaneous treatments for secondary MR throughout the previous decades.

Transcatheter mitral valve repair: review of current techniques

Mitral regurgitation is common and is associated with excess morbidity and mortality. Despite these poor outcomes, only a minority of affected patients undergo mitral surgery, for several reasons, which underlines the substantial unmet need for treatment for this disorder. Transcatheter mitral valve repair interventions have been developed to treat mitral regurgitation in an undertreated patient population. The aim of this status quo review is to provide an overview of currently available transcatheter mitral valve repair techniques, the different approaches and the clinical outcomes reported so far.

Contemporary Reoperative Mitral Valve Surgery: Technical Considerations and Clinical Outcomes

As patients with cardiac disease live longer, reoperative mitral valve surgery has become more common. Although these operations are technically challenging and of high risk, outcomes continue to improve. Minimally invasive techniques, better cardioprotective strategies, and advanced perioperative care have contributed to this. In this review, we discuss surgical approaches, intraoperative strategies, novel catheter-directed devices, and clinical outcomes of contemporary reoperative mitral valve surgery.

Minimally Invasive Mitral Valve Repair for Standalone Secondary Mitral Regurgitation

BACKGROUND

Chronic secondary mitral valve regurgitation is associated with a poor prognosis. Yet, in contrast to primary mitral regurgitation, there is no clear evidence that a reduction in regurgitation improves survival. The limited availability of data regarding secondary mitral regurgitation has resulted in a low level of evidence for treatment recommendations. We evaluated the influence of minimally invasive mitral valve annuloplasty on survival, freedom from recurrent regurgitation, and other echocardiographic parameters in patients with "standalone" secondary mitral valve regurgitation.

METHODS

The analysis included patients with severe secondary mitral regurgitation, left ventricular function <40%, and persistent symptoms, despite optimal medical therapy. We excluded patients who were eligible for coronary artery revascularisation or cardiac resynchronisation therapy (i.e., not standalone mitral regurgitation). After discharge, patients were scheduled for outpatient clinic follow-up at 1, 3, 6, and 12 months.

RESULTS

From 2012 to 2018, 54 consecutive patients underwent minimally invasive mitral valve annuloplasty for severe standalone secondary mitral regurgitation. All patients were discharged with no or trivial residual regurgitation. The mean duration of follow-up was 33.5±16.8 months. Overall survival was 90% at 4 years postprocedure. Freedom from moderate regurgitation or reintervention was 89% at the 4-year follow-up. There was a low incidence of readmission for heart failure and patients showed consistent improvements in left ventricular function and symptoms.

CONCLUSIONS

Mitral valve repair with reduction and stabilisation of the annulus may be beneficial for symptomatic patients with secondary stand-alone mitral regurgitation.

Transcatheter heart valve interventions: where are we? Where are we going?

Transcatheter heart valve interventions have transformed the outcomes of patients with valvular heart disease (VHD) who are unfavourable candidates for surgery. Technological advances have allowed extension of these interventions to younger or lower risk patients and those with other forms of VHD and may in the future permit earlier treatment of VHD in less symptomatic patients or those with moderate disease. The balance of risks and benefits is likely to differ between lower and higher risk patients, and more evidence is needed to evaluate the net benefit of transcatheter technology in these groups. As academic researchers, clinicians, industry, and patient stakeholders collaborate to research these broader indications for transcatheter valve interventions, it is essential to address (i) device durability and deliverability, (ii) specific anatomical needs (e.g. bicuspid aortic valves, aortic regurgitation, mitral and tricuspid valve disease), (iii) operator training, and (iv) the reinforced importance of the multidisciplinary Heart Team.

Prognostic Impact of Redo Transcatheter Mitral Valve Repair for Recurrent Mitral Regurgitation

There is little known about the prognostic impact of a redo transcatheter mitral valve repair (TMVR) for residual or recurrent mitral regurgitation (MR). From January 2011 to March 2019, we identified 43 consecutive patients who underwent a redo TMVR procedure with the MitraClip system. A control cohort was treated medically for MR ≥2+ after the first TMVR and was propensity score 1:1 matched using age, gender, MR severity, trans-mitral pressure gradient, and etiology of MR. To investigate the association of redo TMVR with 1-year mortality, we fitted a Cox proportional hazard model. The technical success rate of redo TMVR was 95%. A reduction in MR to ≤2+ was achieved in 79% of patients, with a significant decline of tricuspid regurgitation pressure gradient and improvement of the New York Heart Association class. After matching was performed, 43 well-matched pairs of patients were analyzed. Redo TMVR patients showed lower 1-year mortality (10.5% vs 37.6%, p = 0.01) compared with the control patients. Redo TMVR was associated with better survival (hazard ratio [HR] 0.26, 95% confidence interval [CI] 0.08 to 0.79, p = 0.02) and lower risk of the composite end point (mortality and rehospitalization due to HF: HR 0.34, 95% CI 0.15 to 0.78; p = 0.01) at 1-year follow-up. The association with the primary end point remained significant after accounting for the New York Heart Association class III/IV, TR ≥severe, the type of MR (i.e., recurrent or residual MR), or the type of previous implanted TMVR device. In conclusion, redo TMVR in selected patients with residual or recurrent MR may be associated with lower 1-year mortality than medical therapy alone.

Percutaneous Interventions for Secondary Mitral Regurgitation

Mitral regurgitation is frequently associated with ventricular dysfunction and carries a high mortality. Guideline-directed medical therapy, surgical mitral valve repair or replacement, and, in the setting of advanced heart failure, heart transplant and left ventricular assist devices have been the mainstay of treatment. However, rapid advancement in the field has resulted in approval of edge-to-edge mitral valve repair with the MitraClip, and there are several novel catheter-based percutaneous options in clinical trials. Percutaneous options, while promising, must be deployed in patients who are most likely to benefit, and thus, understanding the pathophysiology of specific subgroups of patients with functional mitral regurgitation (eg, disproportionate versus proportionate mitral regurgitation) is key to the success of new devices. We review the pathophysiology, percutaneous therapeutic treatment options, and ongoing clinical trials for functional mitral regurgitation.

Percutaneous mitral repair: current and future devices

Mitral regurgitation (MR) is the second most common valvular heart disease and its prevalence is increasing with population ageing. In the recent years we have witnessed the development of several transcatheter devices to correct MR in patients at high-risk for surgery. The majority of evidence regarding safety and efficacy of this new therapy comes from MitraClip studies. However, new alternatives on the field of valve repair have emerged with promising results. The aim of this review is to portrait the landscape of transcatheter mitral repair alternatives, from currently used devices to those that will have a role in the near future.

New developments in transcatheter therapy of mitral valve disease

Mitral valve regurgitation (MR) belongs to one of the most common acquired valve diseases in western countries with increasing prevalence in older age. For patients with high perioperative risk and older age prohibitive for valve surgery, the development of transcatheter mitral valve therapies offers new options. Assessment of the severity and etiology of MR and thorough imaging of the mitral valve anatomy and pathology are necessary prerequisites for appropriate decision making in the field of transcatheter mitral valve therapies. Different transcatheter repair and replacement techniques are on the market, most of them mimicking surgical techniques. With some techniques (e.g., the MitraClip device), there is good clinical experience (>80,000 devices implanted worldwide), and evidence (three randomized studies), whereas for newer procedures, safety and efficacy data are still very limited. Transcatheter mitral repair and replacement techniques have to be considered as complementary treatment options for high-risk patients indicated by the Heart Teams. The different techniques and devices will be introduced and discussed in the following paper.

Transcatheter Electrosurgery: JACC State-of-the-Art Review

Transcatheter electrosurgery refers to a family of procedures using radiofrequency energy to vaporize and traverse or lacerate tissue despite flowing blood. The authors review theory, simulations, and benchtop demonstrations of how guidewires, insulation, adjunctive catheters, and dielectric medium interact. For tissue traversal, all but the tip of traversing guidewires is insulated to concentrate current. For leaflet laceration, the "Flying V" configuration concentrates current at the inner lacerating surface of a kinked guidewire. Flooding the field with non-ionic dextrose eliminates alternative current paths. Clinical applications include traversing occlusions (pulmonary atresia, arterial and venous occlusion, and iatrogenic graft occlusion), traversing tissue planes (atrial and ventricular septal puncture, radiofrequency valve repair, transcaval access, Potts and Glenn shunts), and leaflet laceration (BASILICA, LAMPOON, ELASTA-Clip, and others). Tips are provided for optimizing these techniques. Transcatheter electrosurgery already enables a range of novel therapeutic procedures for structural heart disease, and represents a promising advance toward transcatheter surgery.

Multivalvular Disease: Percutaneous Management in 2019 and Beyond

Patients with multivalvular disease (MVD) are common and often present with heterogeneous valve defects. Evaluation is complicated by interactions among various valve pathologies. Trials and guidelines focus primarily on single-valve disease, providing few recommendations for the treatment of patients with MVD. This article provides an insight into percutaneous treatment possibilities for this heterogeneous patient population.

Treatment of Functional Mitral Regurgitation in Heart Failure

PURPOSE OF REVIEW

To analyze the current state of the art of functional mitral regurgitation (FMR) treatment.

RECENT FINDINGS

The first-line treatment of severe FMR consists of guideline medical therapy (GMT) and resynchronization therapy when indicated; the impact of new medical therapies like sacubitril/valsartan needs further assessment. Valvular intervention may be considered in FMR symptomatic patients despite GMT, and can be performed surgically or percutaneously. MitraClip is a safe percutaneous procedure associated with symptoms improvement. Recently, the COAPT trial showed superior outcomes for MitraClip versus GMT contrasting the MITRA-FR trial which showed no benefit of MitraClip compared with GMT. These results should be interpreted as complementary rather than opposite. The COAPT trial provided a "proof of concept" that percutaneous treatment of severe FMR in patients without too advanced left ventricular disease translates into a prognostic benefit. Careful patient selection will play a critical role in defining the clinical niche for successful interventions.

Direct Percutaneous Mitral Annuloplasty in Patients With Functional Mitral Regurgitation: When and How

Mitral regurgitation (MR) is a frequent valvular disease among patients deemed too high risk for surgery. Echocardiography along with CT is the primary diagnostic tool for MR and offers a comprehensive 3D assessment in patient selection and screening for the optimal treatment method. The direct percutaneous mitral annuloplasty addresses the underlying mechanisms of functional MR with a less invasive, catheter-based approach. The here-described techniques proved a sufficient safety profile, delivered significant MR reduction in most of the cases, and were associated with a notable improvement of symptoms. Although long-term outcome assessment is needed to support these early reports, the percutaneous mitral annuloplasty is likely to set a new standard of treatment in the forthcoming future.

Complications Following Percutaneous Mitral Valve Repair

Mitral valve disease affects more than 4 million people in the United States and it is the second most prevalent valvulopathy in Europe. The gold standard of treatment in these patients is surgical repair or mitral valve replacement. In the last decade, numerous transcatheter therapies have been developed to overcome the increased number of subjects with symptomatic severe mitral regurgitation and high surgical risk. The Mitraclip (Abbott Vascular, Menlo Park, CA), PASCAL (Edwards Lifesciences, Irvine, CA, USA), the Carillon™ Mitral Contour System™ (Cardiac Dimension Inc., Kirkland, WA, USA), the Mitralign™ (Mitralign, Tewksbury, Massachusetts), and the Cardioband (Edwards Lifesciences, Irvine, CA) are the principal percutaneous devices for mitral valve repair. We present an evidence-based clinical update that provides an overview of these technologies and their potential complications.

Refining the prognostic impact of functional mitral regurgitation in chronic heart failure

Aims

Significant efforts are currently undertaken to reduce functional mitral regurgitation (FMR) in patients with chronic heart failure in the hope to improve prognosis. We aimed to assess the prognostic impact of FMR in heart failure with reduced ejection fraction (HFrEF) under optimal medical therapy (OMT) and various conditions of HFrEF. We further intended to identify a heart failure phenotype, where FMR is most likely a driving force and not a mere bystander of the disease.

Methods and results

We prospectively included 576 consecutive HFrEF patients into our long-term observational study. Functional [i.e. New York Heart Association (NYHA) class], echocardiographic, invasive haemodynamic, and biochemical (i.e. NT-proBNP, MR-proANP, MR-proADM, CT-proET-1, copeptin) measurements were performed at baseline. During a median follow-up of 62 months (interquartile range 52-76), 47% of patients died. Severe FMR was a significant predictor of mortality [hazard ratio (HR) 1.76, 95% confidence interval (CI) 1.34-2.30; P < 0.001], independent of clinical (adjusted HR 1.61, 95% CI 1.22-2.12; P = 0.001), and echocardiographic (adjusted HR 1.46, 95% CI 1.09-1.94; P = 0.01) confounders, OMT (adjusted HR 1.81, 95% CI 1.25-2.63; P = 0.002), and neurohumoral activation (adjusted HR 1.38, 95% CI 1.03-1.84; P = 0.03). Subanalysis revealed that severe FMR was associated with poor outcome in an intermediate-failure phenotype of HFrEF i.e. patients with NYHA class II (adjusted HR 2.17, 95% CI 1.07-4.44; P = 0.03) and III (adjusted HR 1.80, 95% CI 1.17-2.77; P = 0.008), moderately reduced left ventricular function (adjusted HR 2.37, 95% CI 1.36-4.12; P = 0.002), and within the second quartile (871-2360 pg/mL) of NT-proBNP (adjusted HR 2.16, 95% CI 1.22-3.86; P = 0.009).

Conclusion

In a patient cohort under OMT, the adverse prognostic impact of FMR is given predominantly in a sub-cohort of a specific intermediate-failure phenotype-well-defined functionally, haemodynamically, biochemically, and morphologically.

Percutaneous Mitral Valve Interventions (Repair): Current Indications and Future Perspectives

Mitral valve regurgitation (MR) is the commonest valvular abnormality encountered among adult patients with cardiac valvular disease and conveys significant morbidity and mortality. The mitral valve is a complex anatomical structure and etiology for regurgitation is classified as either primary or secondary MR. Identification of the etiology in severe MR is critical in determining the appropriate treatment strategy. Transcatheter mitral valve repair (TMVR) is a minimally invasive technique for treatment of selected patients with symptomatic chronic moderate-severe or severe (3 to 4+) MR. While surgery remains the mainstay for treatment in primary MR, several technological advances within the last decade have made transcatheter mitral valve intervention increasingly feasible and safe in clinical practice. Use of TMVR in patients with severe MR has successfully reduced patient symptoms, disease morbidity, improved quality of life, and facilitated reverse remodeling with potential for a survival advantage among certain patients with secondary MR. Recent randomized controlled trials on MitraClip use in secondary MR have reinvigorated interest in this disease and refocused our attention on optimizing patient selection and timing of intervention to maximize benefit from using such percutaneous devices. In our review, we discuss etiologies and pathophysiology in both acute MR and development of chronic severe MR. We discuss management strategies for MR among patients based on etiology, particularly percutaneous mitral valve interventional therapies. We perform an extensive review comparing and contrasting existing data on safety, efficacy, durability, and appropriate patient selection related to MitraClip implantation in both primary and secondary MR. Lastly, we explore percutaneous MV therapies beyond the MitraClip as we await larger scale trials on these devices prior to them making way into day-to-day practice.

Transcatheter Valve Repair for Patients With Mitral Regurgitation: 30-Day Results of the CLASP Study

OBJECTIVES

The authors report the procedural and 30-day results of the PASCAL Transcatheter Valve Repair System (Edwards Lifesciences, Irvine, California) in patients with mitral regurgitation (MR) enrolled in the multicenter, prospective, single-arm CLASP study.

BACKGROUND

Severe MR may lead to symptoms, impaired quality of life, and reduced functional capacity when untreated.

METHODS

Eligible patients had grade 3+ or 4+ MR despite optimal medical therapy and were deemed appropriate for the study by the local heart team. All outcomes were assessed through 30 days post-procedure. Major adverse events (MAEs) were adjudicated by an independent clinical events committee, and echocardiographic images were assessed by a core laboratory. The primary safety endpoint was the rate of MAEs at 30 days.

RESULTS

Between June 2017 and September 2018, 62 patients with grade 3+ or 4+ MR were enrolled. The mean age was 76.5 years, and 51.6% of patients were in New York Heart Association functional class III or IV, with 56% functional, 36% degenerative, and 8% mixed MR etiology. At 30 days, the MAE rate was 6.5%, with an all-cause mortality rate of 1.6% and no occurrence of stroke; 98% had MR grade ≤2+, with 86% with MR grade ≤1+ (p < 0.0001); and 85% were in New York Heart Association functional class I or II (p < 0.0001). Six-minute walk distance improved by 36 m (p = 0.0018), and Kansas City Cardiomyopathy Questionnaire and EQ-5D scores improved by 17 (p < 0.0001) and 10 (p = 0.0004) points, respectively.

CONCLUSIONS

The PASCAL repair system showed feasibility and acceptable safety in the treatment of patients with grade 3+ or 4+ MR. MR severity, irrespective of etiology, was significantly reduced and accompanied by clinically and statistically significant improvements in functional status, exercise capacity, and quality of life. (The CLASP Study Edwards PASCAL Transcatheter Mitral Valve Repair System Study; NCT03170349).

Indirect Annuloplasty to Treat Functional Mitral Regurgitation: Current Results and Future Perspectives

The incidence of mitral regurgitation (MR) is approximately 1.7% in the developed world, and this increases to more than 10% in patients aged over 75 years. Functional (or secondary) mitral regurgitation (FMR) is defined as poor leaflet coaptation and tethering secondary to either ischemic or non-ischemic left ventricular (LV) dysfunction and dilatation. FMR is more common than degenerative (or primary) MR and is associated with significantly worse outcomes in patients with heart failure, post myocardial infarction and following coronary artery bypass graft surgery. Patients with severe degenerative MR have excellent outcomes with surgical repair, however the benefits of surgery in FMR are less clear. Although annuloplasty is associated with a lower operative mortality compared to replacement, the recurrence rate of mitral regurgitation is high in patients with FMR and neither surgical repair or replacement have been shown to reduce hospitalisation or death in FMR. Furthermore, nearly half of patients are deemed too high risk for surgery and therefore most patients are managed conservatively and there remains an unmet clinical need. Transcatheter mitral valve interventions are an emerging alternative for those at high surgical risk. This mini review focuses on indirect mitral annuloplasty: anatomical considerations, patient selection, current devices, implantation techniques and the associated clinical outcome data.

Transcatheter Mitral Valve Implantation with the Medtronic Intrepid™ Transcatheter Mitral Valve Replacement System

Mitral regurgitation is the most prevalent yet undertreated valvulopathy despite its adverse prognosis. With the emergence of transcatheter mitral interventions, the potential for this huge unmet disease burden to be addressed may finally be realized. Medtronic Intrepid™ Transcatheter Mitral Valve Replacement System represents one of several novel solutions. Based on early data from the pilot study, its efficacy and clinical utility is currently being tested against the mainstay treatment of surgical mitral valve replacement in a randomized trial. While there remain significant challenges before transcatheter mitral intervention can become part of the routine treatment algorithm, the authors are optimistic that transcatheter mitral valve repair and intervention have the potential in revolutionizing the management of severe symptomatic mitral regurgitation.