Transcatheter Treatment of Functional Tricuspid Regurgitation Using the Trialign Device

An Animal Model of Functional Tricuspid Regurgitation by Leaflet Tethering Using Image-Guided Chordal Encircling Snares

Several interventional therapies are in development to treat functional tricuspid regurgitation. Most have failed to achieve adequate efficacy, as animal models of this lesion are lacking. We developed a new image-guided technique in swine, by tethering the tricuspid valve chordae using echo-guided chordal encircling snares. Five swine underwent baseline echocardiographic assessment of tricuspid valve function, followed by echo-guided placement of snares that encircle the chordae inserting into the anterior and posterior tricuspid valve leaflets. Tethering these snares and stabilizing them on the right ventricle caused the regurgitant fraction to increase from 8.48±5.38% to 48.76±12.5%, and the valve tenting area to increase from 60.26±52.19 to 160.9±86.92 mm2. Image-guided chordal encircling snares could reproducibly induce clinically significant levels of functional tricuspid regurgitation and create a valve geometry like that seen in patients, providing a new animal model for use to study novel interventional devices.

Transcatheter treatment of the tricuspid valve: current status and perspectives

Transcatheter tricuspid valve interventions (TTVI) are emerging as alternatives to surgery in high-risk patients with isolated or concomitant tricuspid regurgitation. The development of new minimally invasive solutions potentially more adapted to this largely undertreated population of patients, has fuelled the interest for the tricuspid valve. Growing evidence and new concepts have contributed to revise obsolete and misleading perceptions around the right side of the heart. New definitions, classifications, and a better understanding of the disease pathophysiology and phenotypes, as well as their associated patient journeys have profoundly and durably changed the landscape of tricuspid disease. A number of registries and a recent randomized controlled pivotal trial provide preliminary guidance for decision-making. TTVI seem to be very safe and effective in selected patients, although clinical benefits beyond improved quality of life remain to be demonstrated. Even if more efforts are needed, increased disease awareness is gaining momentum in the community and supports the establishment of dedicated expert valve centres. This review is summarizing the achievements in the field and provides perspectives for a less invasive management of a no-more-forgotten disease.

Morphometric Characterization of an Ex Vivo Porcine Model of Functional Tricuspid Regurgitation

Emerging treatments for tricuspid valve (TV) regurgitation require realistic TV pathological models for preclinical testing. The aim of this work was to investigate structural features of fresh and defrosted porcine right-heart samples as models of mild and severe functional tricuspid regurgitation (FTR) condition in ex-vivo pulsatile flow platform. Ten fresh hearts were tested ex-vivo under steady and pulsatile flow in typical right-heart loading conditions. Hemodynamics and 3D echocardiographic imaging of TV and right ventricle (RV) were acquired. Hearts were then kept frozen for 14 days, defrosted, and tested again with the same protocol. Morphometric parameters of TV and RV were derived from 3D reconstructions based on echo data. Fresh samples showed a slightly dilated TV morphology, with coaptation gaps among the leaflets. Sample freezing induced worsening of TV insufficiency, with significant (p < 0.05) increases in annulus size (annulus area and perimeter 7.7-3.1% respectively) and dilation of RV (9.5%), which led to an increase in tenting volume (123.7%). These morphologic alterations reflected into a significant increment of regurgitation fraction (27%). Together, such results suggest that fresh porcine heart samples may be a reliable ex-vivo model of mild FTR condition, which can be enhanced through freezing/thawing treatment to model a severe pathological condition.

Guiding Interventions for Secondary Tricuspid Regurgitation: Follow the Intricate Interplay Between Form and Function

Secondary tricuspid regurgitation (TR) has long been considered a benign and well-tolerated valvular lesion that resolves after treatment of the underlying disease. This view has been challenged by data indicating that long-standing TR can be a progressive disorder, contributing to right ventricular failure and end-organ damage, despite adequate treatment of the underlying disease. Surgical correction is curative, but infrequently performed and historically associated with poor outcomes. This may be due to delayed diagnosis, lack of well-defined surgical indications, and, consequently, late intervention in patients in poor clinical condition with failing right ventricles. Because of limited evidence about timing and corresponding outcome of tricuspid valve surgery, current guideline recommendations are rather conservative and show several inconsistencies. Nevertheless, there has been a trend toward a more aggressive approach in the surgical treatment of TR with improved outcomes. Moreover, emerging transcatheter options claim to provide a lower-risk alternative for selected patients. This may facilitate earlier treatment and improve the attitude toward an early treatment strategy of secondary TR, yet is not reflected in the guidelines. Future research is needed for risk stratification to determine inclusion criteria and optimal timing for intervention.

Heterotopic Transcatheter Tricuspid Valve Replacement in Severe Tricuspid Regurgitation and Refractory Right Heart Failure

Torrential tricuspid regurgitation may lead to heart failure and poor survival and quality of life. Heterotopic transcatheter tricuspid replacement is increasingly offered to patients unsuitable for direct valve repair or replacement. We describe 1 patient treated by transcatheter implantation of 2 self-expanding valves in the venae cavae with a multimodality imaging approach. (Level of Difficulty: Advanced.)

Transcatheter interventions for severe tricuspid regurgitation: a literature review

The prevalence of tricuspid regurgitation (TR) increases with age, affecting 65%-85% of adults. Primary TR is caused by a congenital or acquired abnormality of the tricuspid valve apparatus (leaflets, chordae, papillary muscles, or annulus). Secondary TR is due to insufficient coaptation from dilation of tricuspid valve annulus due to the right ventricle (RV) or right atrium (RA) remodeling and increased RV pressures. Isolated TR is without increased RV pressures and is associated with atrial fibrillation. Mild TR is a benign disease. Moderate to severe tricuspid regurgitation has independently been associated with increased mortality. Most of these patients are treated medically due to poor outcomes with surgical repair of isolated TR. The in-hospital mortality rate is 8.8%, and the median length of stay in hospital is 11 days resulting in higher healthcare costs. Even if the patients undergo surgical repair or replacement, available data do not show improvement in survival. With a more detailed understanding of the complex anatomy and physiology of the tricuspid valve and significant complications from untreated tricuspid valve disease, the approach to the management of TR has shifted from a conservative approach to a process of prevention and intervention. In the past decade, transcatheter tricuspid valve interventions and tricuspid annuloplasty rings have been developed, contributing to decreased mortality from surgical repair. Transcatheter tricuspid valve intervention techniques have improved survival, quality of life, and reduced heart failure rehospitalization. This review summarizes normal anatomy, types of TR, etiology and different mechanisms of TR, echocardiographic assessment of the severe TR, and highlights various percutaneous transcatheter techniques for tricuspid valve repair.

Tricuspid Valve Percutaneous Therapies

PURPOSE OF REVIEW

In this review, we have focused on the currently available transcatheter tricuspid valve therapies, device selection, as well as role and management of tricuspid regurgitation (TR) in the setting of other transcatheter valvular procedures.

RECENT FINDINGS

In this review, we have enlisted the recently finished as well as ongoing trials in the percutaneous tricuspid valve therapies. TR is highly prevalent yet remains underrecognized and is often untreated. TR has traditionally been managed conservatively with medical therapies including diuretics for volume management, whereas surgical therapies are reserved for those undergoing left-sided valvular surgery. Although the transcatheter devices for tricuspid repair and replacement are in clinical trials, the experience to date for their effectiveness and safety has been reassuring.

Transcatheter tricuspid valve intervention techniques and procedural steps for the treatment of tricuspid regurgitation: a review of the literature

Severe tricuspid regurgitation (TR) is an undertreated common pathology associated with significant morbidity and mortality. Classically, surgical repair or valve replacement were the only therapeutic options and are associated with up to 10% postprocedural mortality. Transcatheter tricuspid valve interventions are a novel and effective therapeutic option for the treatment of significant TR. Several devices have been developed with different mechanisms of action. They are classified as annuloplasty devices, replacement devices, caval valve implantation and coaptation devices. In this review, we provide a step-by-step description of the procedural steps and techniques of every device along with video support.

Feasibility Study of a Novel Transcatheter Tricuspid Annuloplasty System in a Porcine Model

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The K-Clip transcatheter tricuspid annuloplasty system simulates the Kay’s procedure: shortening the distance between anterior leaflet and posterior-septal leaflets and resulting in a functionally bicuspid valve.

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The K-Clip system anchors on the annulus tissue using a corkscrew, with no need to cross the valve, and it is easy to adjust the corkscrew position by adjusting the depth and direction of 2 matched deflectable sheaths in the right atrium.

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Results from this study indicate that the K-Clip system may be potentially applicable in treatment of severe tricuspid regurgitation in humans.

Gradually, more attention has been paid to tricuspid regurgitation. Formerly the “forgotten valvular heart disease,” it has been recognized as having high incidence and adverse prognosis if untreated. However, isolated tricuspid valve surgery carries substantial risk and is thus not recommended. The K-Clip transcatheter tricuspid annuloplasty system has recently emerged as a minimally invasive therapeutic option that may help address these unmet clinical needs. The K-Clip technology simulates the Kay’s procedure, which reduces the dimensions of the tricuspid annulus by folding and clamping the tricuspid annulus issue with a rigid clamping device. The feasibility of the K-Clip technology was investigated in this study, and annulus area reduction and declining tricuspid regurgitation grades were noted following the procedure. The findings of this study suggest that the K-Clip system may potentially be applicable as a novel transcatheter tricuspid annuloplasty device for the treatment of severe tricuspid in humans.

[Current technologies in interventional treatment of tricuspid valve regurgitation]

For a long time, severe tricuspid valve regurgitation (TR) was an underestimated disease, especially in the older population and was associated with high morbidity and mortality. Due to the high perioperative mortality of tricuspid valve surgery, historically only pharmaceutical treatment was a practical treatment option. In the first studies interventional approaches could achieve promising results with an effective reduction of TR with simultaneous proof of a convincing safety profile. Conceptually, the currently available interventional treatment options can be divided into three concepts: coaptation systems (edge-to-edge repair), annuloplasty and interventional valve replacement. The largest clinical experience and best scientific body of evidence could so far be generated in the field of coaptation systems. Very promising preliminary results with effective reduction of TR and improvement of the clinical symptoms are, however, also available for interventional valve replacement. Meticulous preprocedural diagnostics with selection of the most suitable treatment option for each individual patient is paramount for successful treatment in this critically ill patient cohort. Future prospective randomized studies will investigate the net benefit of an interventional treatment of TR in comparison to a purely conservative treatment concept.

Morphology and Position of the Right Atrioventricular Valve in Relation to Right Atrial Structures

The right atrioventricular valve (RAV) is an important anatomical structure that prevents blood backflow from the right ventricle to the right atrium. The complex anatomy of the RAV has lowered the success rate of surgical and transcatheter procedures performed within the area. The aim of this study was to describe the morphology of the RAV and determine its spatial position in relation to selected structures of the right atrium. We examined 200 randomly selected human adult hearts. All leaflets and commissures were identified and measured. The position of the RAV was defined. Notably, 3-leaflet configurations were present in 67.0% of cases, whereas 4-leaflet configurations were present in 33.0%. Septal and mural leaflets were both significantly shorter and higher in 4-leaflet than in 3-leaflet RAVs. Significant domination of the muro-septal commissure in 3-leflet valves was noted. The supero-septal commissure was the most stable point within RAV circumference. In 3-leaflet valves, the muro-septal commissure was placed within the cavo-tricuspid isthmus area in 52.2% of cases, followed by the right atrial appendage vestibule region (20.9%). In 4-leaflet RAVs, the infero-septal commissure was located predominantly in the cavo-tricuspid isthmus area and infero-mural commissure was always located within the right atrial appendage vestibule region. The RAV is a highly variable structure. The supero-septal part of the RAV is the least variable component, whereas the infero-mural is the most variable. The number of detected RAV leaflets significantly influences the relative position of individual valve components in relation to right atrial structures.

Multi-Modality Imaging for Interventions in Tricuspid Valve Disease

Several studies have demonstrated that severe tricuspid regurgitation (TR) has a significant negative impact on morbidity and mortality. Nowadays, several therapeutic options to treat TR are available and patients at high surgical risk can also be treated with transcatheter procedures. For the management of patients with TR, an accurate assessment of the tricuspid valve and its surrounding structures is therefore of crucial importance and has gained significant interest in the medical community. Different imaging modalities can provide detailed information on the tricuspid valve apparatus, right ventricle, right atrium, and coronary circulation which are fundamental to define the timing and anatomic suitability of surgical and percutaneous procedures. The present review illustrates the role of 2D and 3D echocardiography, cardiac magnetic resonance, and multidetector row computed tomography for the assessment of the tricuspid valve and right heart with a particular focus on the data needed for planning and guiding interventional procedures.

Mechanical and Structural Evaluation of Tricuspid Bicuspidization in a Porcine Model

INTRODUCTION

Tricuspid regurgitation (TR) affects approximately 1.6 million Americans and is associated with just a 63.9% 1-year survival rate in its moderate to severe forms due to its asymptomatic nature and late diagnosis and surgical referral. As a result, industrial fervor has begun to broach this topic, with several percutaneous treatment devices currently under development. As much remains unknown about the tricuspid apparatus, the mechanics of these procedures remain unquantified. In this study, a testing apparatus and technique for the evaluation of percutaneous tricuspid valve (TV) bicuspidization were developed for the evaluation of these parameters in twelve porcine hearts.

METHODS

The passive relaxed myocardial state and the active contracted state were each induced in six porcine hearts and the bicuspidization experiment was run twice, the second time after induction of TR. TV annular area, cinching force, static leakage through the TV annulus, and annular ellipticity were quantified and compared among the groups.

RESULTS

The use of phenol was effective to induce functional TR by increased annular area. Cinching force was not found to differ between any of the testing states, but the bicuspidization experiment was able to reduce the TR annular area to that of its healthy counterpart in addition to reducing static leakage through the TV annulus. Despite appropriately reducing the area, bicuspidization was found to induce a more circular TV annular shape.

CONCLUSION

Taken together, these results provide a first mechanical analysis of the TV bicuspidization mechanism and may serve as a point of reference for future clinical animal studies.

Transcatheter therapies for severe tricuspid regurgitation. Quo vadis?

Moderate-to-severe tricuspid regurgitation (TR) is common and is associated with a poor prognosis. To date, most patients are undertreated; therefore, transcatheter options could be clinically impactful in those who are denied surgery. Several transcatheter solutions have been developed that address the problem via leaflet enhancement, annuloplasty, or heterotopic implantation of self-expandable or balloon-expandable valves in the caval veins. A comprehensive patient evaluation, based on multimodality imaging techniques for a better understanding of the valvular pathology and TR mechanism, remains paramount for an appropriate device selection. To date, several trials have shown the feasibility and safety of a multitude of devices in this setting, but data from randomized clinical trials regarding clinical benefit based on hard endpoints are still lacking. Although the optimal patient profile and timing of intervention remain under investigation, data from available studies indicate that an earlier treatment referral, before onset of irreversible right ventricular remodeling, could be beneficial. This review discusses the present landscape and future implications of transcatheter therapies for severe TR.

Current state of transcatheter tricuspid valve repair

Tricuspid regurgitation (TR) is a common valvular heart disease affecting >1.6 million people in the United States (US) and >70 million people worldwide. The age- and sex-adjusted prevalence of more than or equal to moderate TR in the US is estimated to be 0.55%. One-year mortality increases with increasing severity of TR. Yet, the majority of patients with severe TR are managed medically in the absence of another indication for cardiac surgery, and isolated tricuspid valve (TV) surgery remains infrequent. To address this unmet clinical need, various transcatheter TV therapies are now being developed as an alternative to surgery in extreme- and high-risk patients with severe functional TR. Transcatheter TV repair devices are aimed at improving leaflet coaptation either directly by bringing the leaflets together (leaflet/coaptation devices) or indirectly by repairing the dilated annulus (annuloplasty devices). In this review, we describe the current state of transcatheter TV repair therapies and summarize the available data on the efficacy and safety of various devices. Procedural and clinical outcomes of transcatheter TV repair therapies are expected to improve in the coming years with technological advancement, newer device iterations, and increased experience in this field. Appropriate patient selection, optimal timing of intervention, and evaluation of long-term outcomes and device durability will be key in ongoing and future studies.

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.

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.

Transcatheter Tricuspid Valve Interventions: An Emerging Field

PURPOSE OF REVIEW

This review aims to provide an updated overview and a clinical perspective on novel transcatheter tricuspid valve interventions (TTVI), highlighting potential challenges and future directions.

RECENT FINDINGS

Severe tricuspid regurgitation (TR) is a predictor of mortality. However, a sizeable number of patients remain untreated until the end-stage when cardiac surgery presents a prohibitive risk. The emergent need in finding a treatment for patients with TR, deemed for surgery options, has encouraged the development of TTVI. These procedures mimic classical surgery techniques and are mainly divided in four categories: annuloplasty and coaptation devices, edge-to-edge techniques and transcatheter tricuspid valve replacement. Early studies showed promising results, but long-term follow-up data are not available. For patients with severe TR and high surgical risk, several percutaneous options are available. However, these therapies are in a growing phase and bigger studies and long term follow-up are needed to prove their efficacy.