First-in-Human Implantations of the NaviGate Bioprosthesis in a Severely Dilated Tricuspid Annulus and in a Failed Tricuspid Annuloplasty Ring

Advances in transcatheter mitral and tricuspid therapies

BACKGROUND

While rheumatic mitral stenosis has been effectively treated percutaneously for more than 20 years, mitral and tricuspid regurgitation treatment appear as a contemporary unmet need. The advent of transcatheter therapies offer new treatment options to often elderly and frail patients at high risk for open surgery. We aimed at providing an updated review of fast-growing domain of transcatheter mitral and tricuspid technology.

MAIN BODY

We reviewed the existing literature on mitral and tricuspid transcatheter therapies. Mitraclip is becoming an established therapy for secondary mitral regurgitation in selected patients with disproportionately severe regurgitation associated with moderate left ventricle dysfunction. Evidence is less convincing for primary mitral regurgitation. Transcatheter mitral valve replacement is a promising emerging alternative to transcatheter repair, for secondary as well as primary mitral regurgitation. But further development is needed to improve delivery. Transcatheter tricuspid intervention arrives late after similar technologies have been developed for aortic and mitral valves and is currently at its infancy. This is likely due in part to previously under-recognized impact of tricuspid regurgitation on patient outcomes. Edge-to-edge repair is the most advanced transcatheter solution in development. Data on tricuspid annuloplasty and replacement is limited, and more research is warranted.

CONCLUSION

The future appears bright for transcatheter mitral therapies, albeit their place in clinical practice is yet to be clearly defined. Tricuspid transcatheter therapies might address the unmet need of tricuspid regurgitation treatment.

Developments in transcatheter tricuspid valve therapies

Introduction: Transcatheter tricuspid valve (TV) procedures emerged as an alternative to surgery for symptomatic high-risk patients with severe tricuspid regurgitation.Areas covered: A literature search was performed using PubMed. Authors review clinical evidence in this field, the imaging features and the developments in TV transcatheter technologies. Currently, transcatheter devices for TV procedures can be allocated into four main groups: 1) those ones targeting leaflet malcoaptation, 2) those addressing annular dilatation, 3) those performing heterotopic valve implantation and 4) those onesaccomplishing a complete transcatheter replacement of the valve.Expert opinion: Actually, encouraging results are provided by initial experience in the field of transcatheter TV procedures. However, this field remains full of challenges that faced could lead to better results and prognosis for the patients. The next steps in this emerging field will need to focus on accurate patient selection, an early patient referral and on studies comparable and providing long-term data.

Uncertainties and challenges in surgical and transcatheter tricuspid valve therapy: a state-of-the-art expert review

Tricuspid regurgitation (TR) is a frequent and complex problem, commonly combined with left-sided heart disease, such as mitral regurgitation. Significant TR is associated with increased mortality if left untreated or recurrent after therapy. Tricuspid regurgitation was historically often disregarded and remained undertreated. Surgery is currently the only Class I Guideline recommended therapy for TR, in the form of annuloplasty, leaflet repair, or valve replacement. As growing experience of transcatheter therapy in structural heart disease, many dedicated transcatheter tricuspid repair or replacement devices, which mimic well-established surgical techniques, are currently under development. Nevertheless, many aspects of TR are little understood, including the disease process, surgical or interventional risk stratification, and predictors of successful therapy. The optimal treatment timing and the choice of proper surgical or interventional technique for significant TR remain to be elucidated. In this context, we aim to highlight the current evidence, underline major controversial issues in this field and present a future roadmap for TR therapy.

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Specific Anatomic Considerations for Tricuspid Interventions

PURPOSE OF REVIEW

This review discusses the normal anatomy and pathology of the tricuspid valve (TV) and right side of the heart. Emphasis is on those anatomic and pathologic features relevant to interventions intended to restore normal function to the TV in disease states.

RECENT FINDINGS

TV pathology is less common than aortic and mitral valve pathology, and treatment and outcomes for interventions face considerable hurdles. New innovations and early data showing safety and efficacy in transcatheter interventions have transformed TV interventions into the next frontier in cardiac valve disease treatment. Certain features of the TV and right heart have presented themselves as potential targets, as well as impediments, for TV intervention. The causes of TV pathology and the anatomy of the TV and right heart bring unique challenges to intervention. Approaches to intervention will continue to progress and change the way we view and treat TV pathology.

Update on the Current Landscape of Transcatheter Options for Tricuspid Regurgitation Treatment

Most patients with severe tricuspid regurgitation lack treatment options because of prohibitive surgical risk. New transcatheter treatments under development and investigation might be able to address this unmet clinical need. This article gives an update on the landscape of devices for transcatheter tricuspid regurgitation treatment including different approaches (i.e. repair with leaflet approximation or annuloplasty and replacement using orthotopic or heterotopic valves) at different stages of development, from experimental to clinical trial. Repair devices such as the Cardioband or the MitraClip are leading the field with promising preliminary data and further trials are ongoing. However, with implantations of the Gate bioprosthesis, replacement devices are catching up. Potential advantages of different approaches and most recent data are discussed.

Percutaneous tricuspid valve implantation in failing bioprosthesis

Severe tricuspid valve (TV) dysfunction in patients with congenital heart disease (CHD) is usually treated by open heart surgery in relatively young patients. If a valve plasty is not possible, a biological valve is implanted with a limited durability. Due to valve degeneration repeated valve exchanges are necessary in these patients. To expand the lifetime of a bioprosthesis in tricuspid position percutaneous TV implantation (PTVI) was introduced recently. PTVI is a promising new catheter interventional technology. The current review summarizes the indication for PTVI, describes the procedure itself and gives an outlook on medium to long-term results of this catheter intervention. PTVI in patients with severe TV dysfunction is less invasive, safe and effective, if performed by an experienced operator, and may help to reduce the total number of open-heart surgeries during a patient's life time. However, further studies with larger patient numbers and longer follow-up are needed.

Transcatheter Tricuspid Valve Replacement: Principles and Design

Tricuspid regurgitation (TR) may affect as much as 65-85% of the population with the prevalence of moderate-to-severe TR in the United States reported at greater than 1.6 million. However, only 8,000 tricuspid valve operations are performed annually in the United States. As severe TR is associated with poor outcomes, there is an unmet clinical need for surgical or percutaneous transcatheter based treatment of TR. Over the last two decades there have been significant developments in percutaneous transcatheter based therapies for valvular disease. However, this progress has not been mirrored for the tricuspid valve until recently; we are now at a cross-roads of new transcatheter devices becoming available for treatment of TR. In this review, we discuss the principles of performing transcatheter tricuspid valve replacement, analyze the devices that can be utilized and outline the challenges related to this procedure.

Multi-Modality Imaging in the Evaluation and Treatment of Tricuspid Regurgitation

PURPOSE OF REVIEW

The goal of this review is to cover the epidemiology of tricuspid regurgitation (TR), anatomy of the tricuspid valve (TV), and the mechanisms and modern treatment of TR. The focus will be on the role of echocardiography, cardiac CT, and MRI to determine the mechanism, severity, and management strategies of TR.

RECENT FINDINGS

The evaluation and management of TR is a rapidly growing field with significant advances in both imaging and interventions. Important advances have been made to understand TV anatomy and physiology in 3D echo, CT, and MRI. Additional understanding of the abnormal outcomes in both primary TR and secondary TR have been appreciated. Multiple transcatheter devices have reached the stage of early trials in high surgical risk cohorts with favorable initial findings. TR is a significant cardiovascular problem and vastly undertreated in the present era. There has been tremendous growth in knowledge of mechanisms of TR, its prognostic implications, timing of intervention, and development of novel treatment strategies. Multimodality imaging plays a key role in evaluation and treatment of this condition.

The future of percutaneous tricuspid valve interventions

Tricuspid valve regurgitation has a high prevalence and, when severe, is associated with poor outcomes. Nevertheless, surgical repair or replacement (isolated or as a part of a combined procedure) is rarely performed due to high surgical risk. Therefore, there is a significant unmet clinical need for percutaneous transcatheter-based treatments. Significant development in percutaneous therapies for both aortic and mitral valve disease has been accomplished over the last two decades, while transcatheter therapies for the tricuspid valve are still at an early stage. We are today at a cross-road of new transcatheter devices that are becoming available for the treatment of tricuspid regurgitation; the current review evaluates the challenges that current and future technologies have to face in order to become a safer, less invasive and equally effective alternative to surgery.

Tricuspid Regurgitation - Medical Management and Evolving Interventional Concepts

Severe tricuspid regurgitation (TR) is a complex condition of the right ventricle (RV) and tricuspid valve apparatus and is frequently associated with symptomatic heart failure and a significant morbidity and mortality. In these patients, left heart pathologies lead to chronic pressure overload of the RV, eventually causing progressive RV dilatation and functional TR. Therefore, TR cannot be considered as isolated heart valve disease pathology but has to be understood and treated as one component of a complex structural RV pathology and is frequently also a marker of an advanced stage of cardiac disease. In these patients, medical therapy restricted to diuretics and heart failure medication is frequently ineffective. Also, severe TR in the setting of advanced heart failure constitutes a high risk for cardiac surgery. Neither one of these treatment options has demonstrated a beneficial effect on long-term prognosis. The recent innovations in transcatheter technology led to efforts to develop interventional approaches to severe TR. Multiple innovative treatment concepts are currently under preclinical and clinical investigation to replace or repair TV function. However, up to date none of these approaches is established and there is still a lack of clinical data to support the efficacy of transcatheter TR treatment.

"Guidelines Recommendations on the Treatment of Tricuspid Regurgitation. Where Are We and Where Do We Go With Transcatheter Valve Intervention"

Tricuspid regurgitation (TR) is an important clinical problem because it is frequent and carries a poor prognosis when it is left uncorrected. However, there is still a lack of awareness of tricuspid disease in the medical community. The indications for evaluation and surgical interventions in patients with TR were recently updated in the ESC/EACTS guidelines. Transcatheter tricuspid valve intervention (TTVI), almost exclusively valve repair, is at an early stage of development as only a few hundreds of patients have been treated. The first-in-man valve implantation was very recently performed. The recent ESC/EACTS Guidelines state that “The potential role of transcatheter tricuspid valve treatment in high-risk patients needs to be determined”. We shall review here which lessons of interest for TTVI can be learned from the Guidelines as regards evaluation and indications for surgery and try to imagine what could be the place of TTVI in the Guidelines in the future.

Percutaneous tricuspid valve replacement: orthotopic and heterotopic valves

The tricuspid valve has long been described as the "forgotten valve", leaving tricuspid valve disease relatively neglected. However, the number of people in the United States affected by severe tricuspid regurgitation is growing. Isolated surgery for severe tricuspid regurgitation in the setting of right ventricular heart failure carries a high mortality risk, and therefore, attention to corrective therapies has increased. Because of the different etiologies for tricuspid regurgitation, multiple percutaneous transcatheter options for tricuspid valve repair for severe regurgitation are being studied and have been developed, including annuloplasty systems, leaflet and coaptation devices, vena caval (heterotopic) valve implantations, and tricuspid valve (orthotopic) replacement. In this paper, we review the heterotopic and orthotopic tricuspid valve transcatheter options for severe tricuspid regurgitation.

Transcatheter Tricuspid Valve Implantation of NaviGate Bioprosthesis in a Preclinical Model

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Surgery for isolated tricuspid regurgitation carries a high mortality risk, especially in the setting of right ventricular dysfunction and reoperation.

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Transcatheter valve therapy is as promising alternative for treatment of isolated tricuspid valve disease associated with right heart failure.

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The NaviGate bioprosthesis is a novel self-expanding valved stent designed to treat functional tricuspid regurgitation.

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The preclinical evaluation shows that transcatheter tricuspid valve implantation using the NaviGate device is safe, is feasible through 2 different approaches, and results in a secure and stable engagement of the native annulus, with excellent hemodynamic and valve performance.

Patients with isolated functional or recurrent tricuspid regurgitation are often denied surgery because they are considered to be at high risk. Transcatheter valve therapy provides a less invasive alternative for tricuspid regurgitation associated with right heart failure. We have evaluated the feasibility of transcatheter tricuspid valve implantation of the NaviGate valved stent in a long-term swine model. The valved stent was successfully implanted through transjugular and transatrial approaches on the beating heart with excellent hemodynamic and valve performance. No conduction disturbance or coronary obstruction was observed. This technology could provide an alternative treatment for patients who are at high surgical risk with severe tricuspid regurgitation and compromised right ventricular function.