The posterior mitral leaflet overhang: A rare yet possible complication of percutaneous mitral valve procedures

The two surgical options for mitral valve regurgitation are replacement and repair, with annuloplasty being the cornerstone of correction. In cases of repair failure, especially in high surgical risk patients, transcatheter mitral valve-in-ring (MViR) procedures represent emerging and challenging options. Among the several complications linked to this treatment, this paper delves into the role that native mitral leaflets may play in precipitating acute bioprosthesis dysfunction in the MViR procedure. The literature extensively covers complications related to the anterior leaflet, including risks such as outflow tract obstruction and residual mitral insufficiency due to interaction between native and prosthetic leaflets. Conversely, complications involving the posterior leaflet are less understood and often overlooked. In this gap in the literature, we present a clinical case highlighting how a redundant native posterior mitral leaflet can unexpectedly lead to acute severe mitral insufficiency by interfering with prosthetic leaflets.

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.

Transcatheter mitral valve-in-valve and valve-in-ring replacement: Lessons learned from bioprosthetic surgical valve failures

INTRODUCTION

Limited data are available about the outcomes of transcatheter mitral valve replacement (TMVR) using transseptal approach in patients with prior mitral valve repair (valve-in-ring) or replacement (valve-in-valve) (TMViVR) and on modes of the prior surgical valve failures. We report our tertiary center TMVR experience in high surgical risk patients with prior mitral valve repair or replacement.

METHODS

From December 2016 to January 2020, patients with symptomatic severe mitral valve stenosis and/or insufficiency at increased redo surgical risk were included. TMViVR was performed off-label with Sapien S3 valve (Edwards Lifesciences). Patients were followed within 30-days and 1-year from the procedure.

RESULTS

Twenty-seven patients underwent transcatheter mitral valve-in-valve (n = 21) or valve-in-ring (n = 6) replacement. Mean ± SD age was 71.8 ± 11 years with Society of Thoracic Surgeons' calculated mortality 7.1 ± 4.6%. The etiology of valve failure was stenosis in 17 (63%) patients, insufficiency in 4 (14.8%) patients, and both in 6 (22.2%) patients. TMViVR technical success was 100% in all patients. Left ventricular outflow track (LVOT) obstruction was observed in only one (3.7%) patient. Zero patients had moderate or severe central mitral valve regurgitation or paravalvular leak. All patients had symptomatic improvement at 30 days. The mean transmitral diastolic pressure gradient decreased from 14.1 ± 4.6 to 6.9 ± 4.6 mm Hg (p < .001) at 30 days. The one patient with LOVT obstruction required readmission at 5-months. One-year survival was 95%. At 1-year mean gradients remained lower than the baseline (7.0 ± 3.0 vs. 12.4 ± 4.0, p = .002).

CONCLUSIONS

Transcatheter mitral valve-in-valve and valve-in-ring replacement is feasible and safe. The improvement in mitral valve hemodynamics appears to be durable.

Current Devices and Complications Related to Transcatheter Mitral Valve Replacement: The Bumpy Road to the Top

Mitral regurgitation is the most common valvular lesion in the developed world, with increasing prevalence, morbidity, and mortality. The experience with surgical mitral valve repair or replacement is very well-validated. However, more than 45% of these patients get denied surgery due to an elevated risk profile and advanced disease of the left ventricle at the time of presentation, promoting the need for less invasive transcatheter options such as transcatheter repair and transcatheter mitral valve replacement (TMVR). Early available TMVR studies have shown promising results, and several dedicated devices are under clinical evaluation. However, TMVR is still in the early developmental stages and is associated with a non-negligible risk of periprocedural and post-procedural complications. In this review, we discuss the current challenges facing TMVR and the potential TMVR-related complications, offering an overview on the measures implemented to mitigate these complications, and future implications.

Transcatheter edge-to-edge mitral valve repair for annuloplasty ring dehiscence: The peri-ring approach

Recurrent severe primary mitral regurgitation from annuloplasty ring dehiscence is very rare and is associated with adverse outcomes. We present a case where transcatheter edge-to-edge mitral repair with MitraClip was used in high surgical risk patient using a peri-ring approach due to unfavorable anatomy for a conventional intra-ring approach.

Reoperative Mitral Surgery Versus Transcatheter Mitral Valve Replacement: A Systematic Review

Bioprosthetic mitral structural valve degeneration and failed mitral valve repair (MVr) have traditionally been treated with reoperative mitral valve surgery. Transcatheter mitral valve-in-valve (MVIV) and valve-in-ring (MVIR) replacement are now feasible, but data comparing these approaches are lacking. We sought to compare the outcomes of (1) reoperative mitral valve replacement (redo-MVR) and MVIV for structural valve degeneration, and (2) reoperative mitral valve repair (redo-MVr) or MVR and MVIR for failed MVr. A literature search of PubMed, Embase, and the Cochrane Library was conducted up to July 31, 2020. Thirty-two studies involving 25 832 patients were included. Redo-MVR was required in ≈35% of patients after index surgery at 10 years, with 5% to 15% 30-day mortality. MVIV resulted in >95% procedural success with 30-day and 1-year mortality of 0% to 8% and 11% to 16%, respectively. Recognized complications included left ventricular outflow tract obstruction (0%-6%), valve migration (0%-9%), and residual regurgitation (0%-6%). Comparisons of redo-MVR and MVIV showed no statistically significant differences in mortality (11.3% versus 11.9% at 1 year, P=0.92), albeit higher rates of major bleeding and arrhythmias with redo-MVR. MVIR resulted in 0% to 34% mortality at 1 year, whereas both redo-MVr and MVR for failed repairs were performed with minimal mortality and durable long-term results. MVIV is therefore a viable alternative to redo-MVR for structural valve degeneration, whereas redo-MVr or redo-MVR is preferred for failed MVr given the suboptimal results with MVIR. However, not all patients will be candidates for MVIV/MVIR because anatomical restrictions may preclude transcatheter options from adequately addressing the underlying pathology.

Transcatheter mitral valve replacement: latest advances and future directions

Mitral regurgitation remains the most common form of valve disease worldwide and given an aging population with a significant proportion of secondary mitral regurgitation, a transcatheter approach to mitral valve replacement has become a major goal of the transcatheter therapeutics field. Mitral regurgitation can be caused by disease of the leaflets (primary) or by diseases of the left atrium or left ventricle (LV) (secondary or functional), and may involve overlap of the two (mixed disease). The location of the mitral valve (and large size), the approach to anchoring a valve replacement, and concerns about left ventricular outflow tract (LVOT) obstruction are all issues that have made the transcatheter delivery of a valve replacement challenging. Despite these challenges, both transapical and transseptal devices are currently being developed, with several in early feasibility trials and several entering pivotal trials. As the field of transcatheter mitral valve replacement (TMVR) improves and develops, a critical part of evaluating patients with mitral valve disease will be utilizing the heart team approach to identify and individualize the most appropriate treatment for each patient.

Neo-LVOT and Transcatheter Mitral Valve Replacement: Expert Recommendations

With the advent of transcatheter mitral valve replacement (TMVR), the concept of the neo-left ventricular outflow tract (LVOT) was introduced and remains an essential component of treatment planning. This paper describes the LVOT anatomy and provides a step-by-step computed tomography methodology to segment and measure the neo-LVOT while discussing the current evidence and outstanding challenges. It also discusses the technical and hemodynamic factors that play a major role in assessing the neo-LVOT. A summary of expert-based recommendations about the overall risk of LVOT obstruction in different scenarios is presented along with the currently available methods to reduce the risk of LVOT obstruction and other post-procedural complications.

Transcatheter Mitral Valve Replacement: Rationale and Current Status

Mitral regurgitation (MR) is the most prevalent form of moderate or severe valve disease in the developed world. MR can result from impairment of any part of the mitral valve apparatus and is classified as primary (disease of the leaflets) or secondary (functional). The presence of at least moderate MR is associated with increased morbidity and mortality. With the goal of avoiding the risks of traditional surgery, transcatheter mitral valve therapies have been developed. The current transcatheter repair techniques are limited by therapeutic target and incomplete MR reduction, and thus transcatheter mitral valve replacement (TMVR) has been pursued. Several devices (both transapical and transseptal) are under development, with both early feasibility and pivotal trials under way. As this field develops, the decision to treat with TMVR will require a heart team approach that takes patient-, disease-, and device-specific factors into account.

Treatment of severe mitral regurgitation that mimics a para-ring mitral regurgitation after failed annuloplasty ring with MitraClip: A case report

Background

Progressive remodelling of the left ventricle with lateral and apical displacement of one or both papillary muscles can lead to recurrence of severe mitral regurgitation (MR) in the presence of the mitral valve (MV) ring. The MitraClip (Abbott, USA) is the only option in cases with annuloplasty rings too large for implantation of a Sapien prosthesis in high surgical-risk patients. We present a case where the MR jet was directed toward a para-ring hole, and the MitraClip system was used successfully to treat this severe MR.

Case summary

An 80-year-old woman underwent coronary artery bypass surgery plus MV repair with C-shaped ring 6 years ago. In the past year, she experienced severe shortness of breath; her ejection fraction dropped to 15%. A transesophageal echocardiogram revealed that severe MR started at the level of MV leaflets and then passed to the left atrium beside the MV ring. Live 3D showed the severe MR coming through the oval-shaped hole beside the C-shaped MV repair ring. MitraClip implantation was decided, the two leaflets were grasped successfully, the clip was fully closed, and only trace MR remained at the MV leaflets with no flow to the para-ring hole. The patient was extubated after 12 hours and discharged home after 2 days. Follow-up transthoracic echocardiography after 6 months showed the clip in place and trace residual MR.

Conclusion

Implantation of MitraClip in the presence of MV repair ring is feasible and safe. The para-ring defect can be left if the origin of MR from the MV coaptation line is treated successfully with MitraClip. Symptomatic improvement with no rehospitalization was documented in this case.

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.

Transcatheter Mitral Valve-in-Ring Implantation in the Flexible Adjustable Attune Annuloplasty Ring

Transcatheter mitral valve-in-ring implantation (TMViR) poses unique challenges when compared to valve-in-valve implantation due to the large variation in the different annuloplasty rings used. Annuloplasty rings are often classified according to whether they are complete or incomplete, rigid, semi-rigid, or flexible, and whether their three-dimensional geometry is saddle-shaped or flat. A limited number of annuloplasty rings are available which are adjustable allowing the surgeon to increase or decrease the size of the ring once it has been sutured in place. To our knowledge there has been no description of TMViR in such adjustable complete rings and recommendations on THV sizing and implantation are not available on the Valve-in-Valve application. Here we report a case of TMViR in an adjustable annuloplasty ring (Attune ring, Abbott, Chicago, IL, USA) and review the literature on TMViR.

Transesophageal echocardiography guidance of percutaneous mitral valve replacement in failed annuloplasty ring: A case report

Severe mitral regurgitation and stenosis due to failed mitral annuloplasty ring can be managed with percutaneous mitral valve in ring in high surgical risk patients. A 66-year-old male underwent coronary artery bypass surgery and mitral valve ring annuloplasty 7 years previously. He started to have shortness of breath with minimal effort in the past 2 years. Transthoracic echocardiogram revealed a new severe mitral regurgitation and severe mitral stenosis. The patient was turned down from surgery due to high surgical risk. The transcatheter mitral valve in ring implantation was decided. In this case, there was a low probability of left ventricular outflow tract obstruction. A stiff wire crossed the mitral valve ring and positioned in the left ventricular apex. The Sapien 3 valve size 26 mm (Edwards Lifesciences, Irvine, CA, USA) was positioned to have 80% ventricular and 20% atrial side. Transesophageal echocardiogram evaluation revealed a mean gradient of 5 mmHg. The left ventricular outflow tract (LVOT) had laminar color flow and the mean pressure gradient across LVOT was 1 mmHg. The patient was discharged after 2 days in good condition. At one year follow up, he had no shortness of breath and no rehospitalization. In conclusion, the percutaneous mitral valve in ring is feasible in selected patients. The risk of LVOT obstruction should be assessed carefully before the procedure with a transthoracic and transesophageal echocardiogram. 〈Learning objective: Understand how to guide the mitral valve in ring procedure with a transesophageal echocardiogram and how to avoid left ventricular outflow tract obstruction. Understand how to position the Sapien valve in mitral valve ring.〉.

Valve-in-Valve in a Flail Bioprosthetic Mitral Valve With Endocarditis Using a Novel Embolic Protection Device

A 79-year-old woman presented in cardiogenic shock with a flail bioprosthetic mitral valve leaflet and Staphylococcus aureus endocarditis. In the absence of other viable options, transfemoral valve-in-valve transcatheter mitral valve replacement was performed with a novel embolic protection device, resulting in trace mitral regurgitation and no neurologic complications. (Level of Difficulty: Advanced.).

Balloon assisted translocation of the mitral anterior leaflet to prevent left ventricular outflow obstruction (BATMAN): A novel technique for patients undergoing transcatheter mitral valve replacement

INTRODUCTION

Transcatheter mitral valve replacement (TMVR) is an option for patients at high risk for mitral valve replacement or repair via sternotomy or left thoracotomy approach. TMVR carries up to 22% risk of left ventricular outflow tract (LVOT) obstruction. Severe LVOT obstruction can have devastating hemodynamic and clinical consequences.

HYPOTHESIS

We previously presented a novel technique to prevent LVOT obstruction during transapical retrograde mitral valve replacement, by penetrating and ballooning the anterior mitral leaflet (AML), resulting in creation of a "hole" and posterior translocation of AML, then deploying the valve.

METHODS

Three patients underwent TMVR at Saint Louis University for severe mitral regurgitation after being deemed too high risk for surgery, and not candidates for a Mitra-clip procedure. These patients were deemed to be at risk for LVOT obstruction based on the preprocedural evaluation. Via transapical approach, a needle was advanced "through," perforating the AML and wire was placed in the left atrium. Over the wire, an 20-mm valvuloplasty balloon was positioned "within" the anterior leaflet and inflated leading to translocation of the AMVL. Then the valve was deployed.

RESULTS

This novel technique has been performed on three patients at our institution. Sapien S3 transcatheter valves were used in all three patients, with 100% procedural success rate. Intraoperative TEE demonstrated no significant LVOT obstruction, cardiopulmonary bypass time was 42-44 min.

CONCLUSION

The balloon assisted translocation of the mitral anterior leaflet to prevent left ventricular outflow obstruction technique described here may offer the option of transcatheter mitral valve implantation in patients at high risk of LVOT obstruction. A variation of this technique to allow application in cases with transseptal approach is under investigation.

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 aortic valve-in-ring implantation: feasibility in an acute, preclinical, pilot trial

OBJECTIVES

The HAART ring device has been introduced as a novel strategy to facilitate aortic valve repair. This rigid, elliptical device aims to restore normal leaflet configuration and to provide annular stabilization in the setting of aortic regurgitation. The goal of this preclinical study is to evaluate the in vivo feasibility of 'aortic valve-in-ring' transcatheter aortic valve replacement (TAVR).

METHODS

Six animals {landrace pigs, 87.6 [standard deviation (SD) 4.5] kg} underwent HAART ring implantation (5 cases #19 mm and 1 case #21 mm) via full sternotomy with cardiopulmonary bypass. Seven transfemoral TAVR implantations were performed with the Medtronic EvolutR prosthesis to assess the sizing and outcome (5 cases #23 mm, 1 case #26 mm and 1 case #29 mm).

RESULTS

TAVR implantation was successful in 6 of 7 attempts. Post-dilatation was performed in 1 case without damage of the ring or the valve. One embolization occurred due to oversizing (EvolutR valve 29 mm in HAART ring 19 mm). No clinically relevant postimplantation gradient [7.6 (SD 4.0) mmHg] or regurgitation was detected by invasive and echocardiographic measurements. Postoperative computed tomography scans revealed good device configuration.

CONCLUSIONS

Transcatheter aortic valve-in-ring implantation of a self-expandable TAVR into a rigid aortic annuloplasty ring after aortic valve repair appears feasible. Proper sizing and correct depth of implantation are crucial.

Cerebral Embolic Risk During Transcatheter Mitral Valve Interventions: An Unaddressed and Unmet Clinical Need?

As new transcatheter mitral valve (MV) interventions continuously evolve, potential procedure-related adverse events demand careful investigation. The risk of cerebral embolic damage is ubiquitous in any left-sided structural heart intervention (and potentially linked to long-term neurocognitive sequelae); therefore, efforts to evaluate these aspects in the field of catheter-based MV procedures are justified. Given the peculiarities of MV anatomy, MV disease, and MV procedures, the lessons learned from other transcatheter heart interventions (i.e., transcatheter aortic valve replacement) cannot be directly translated to MV applications. Through a systematic assessment of available evidence, the authors present and discuss procedure- and patient-related factors potentially associated with cerebral embolic risk during catheter-based MV interventions. Given the paucity of available data in this field, future large, dedicated studies are needed to understand whether cerebral embolic injury represents a real clinical issue during MV procedures.

Left Ventricular Outflow Tract Obstruction: A Potential Obstacle for Transcatheter Mitral Valve Therapy

Transcatheter mitral valve replacement is the focus of much enthusiasm as the future of therapy for mitral valve disease. Despite technological advances, left ventricular outflow tract (LVOT) obstruction from the valve prosthesis remains an important issue. In this review the authors discuss the pathophysiology of LVOT obstruction in both the surgical and transcatheter experience, imaging evaluation preprocedure, outcomes to date, and therapeutic options.

Redo mitral valve surgery following prior mitral valve repair

BACKGROUND

The optimal treatment strategy following a failed mitral valve repair remains unclear. This study evaluated early and long-term outcomes of redo mitral valve repair (MVr) and replacement (MVR) after prior mitral valve repair.

METHODS

Patients undergoing redo mitral valve surgery after prior mitral valve repair at a single institution between 2002 and 2014 were reviewed. Primary outcomes included operative mortality (30-day or in-hospital mortality) and long-term freedom from mitral valve reoperation and death. Secondary outcomes included postoperative complications.

RESULTS

305 patients underwent redo MVr (n = 48) or MVR (n = 257) after prior mitral valve repair. Concomitant procedures included tricuspid valve repair or replacement (23%), aortic valve replacement (6%), and coronary artery bypass grafting (4%), with no differences between cohorts. 18% were performed via right mini-thoracotomy (24% MVr vs 18% MVR, P = 0.31). Unadjusted and risk-adjusted operative mortality were lower with MVr (0% vs 8%, P = 0.04). Rates of postoperative complications were similar except for blood product transfusion (35% MVr vs 59% MVR, P = 0.003) and prolonged mechanical ventilation (8% MVr vs 29% MVR, P = 0.003). Long-term freedom from mortality was comparable: 96% MVr versus 86% MVR at 1 year and 78% MVr versus 68% MVR at 5 years (P = 0.29).

CONCLUSIONS

When technically feasible, mitral valve re-repair can be safely performed with outcomes comparable to MVR.

Percutaneous Techniques, Limitations and Challenges for the Failed Surgical Mitral Intervention

The advent of percutaneous therapies has significantly altered therapeutic options for patients with valvular heart disease. Building on the success of transcatheter aortic valve replacement, both expanded indications and purpose-built devices are now being used to address percutaneous approaches for mitral valve pathology. While surgical mitral valve repair remains the gold standard for addressing significant mitral valve pathology, there has been a progressive increase in the utilization of bioprosthetic valves despite their limited lifespan. The risks of reoperation to address mitral valve repair failure or bioprosthetic valve dysfunction is not insignificant. In light of the aging population and the potential for significant associated comorbidities, less invasive alternative techniques hold particular appeal. Utilization of commercially available transcatheter aortic valve replacement valves for failed surgical valves has been shown to have better short-term mortality than would be predicted for open reoperation. As a result, the US Food and Drug Administration approved the utilization of transcatheter mitral valve-in-valve replacement for the failed bioprosthetic valve in high surgical risk patients. Despite the favorable outcomes, transcatheter mitral valve-in-valve is not without procedural challenges and potential complications including malpositioning, embolization, paravalvular leak, and outflow tract obstruction. Awareness of these challenges, mitigation strategies, and therapeutic options is imperative to optimizing outcomes in this high-risk patient population.

Novel mitral valve technologies-transcatheter mitral valve implantation: a systematic review

Background

Valvular heart disease is an important cause of morbidity and mortality throughout the world; in industrialized nations, mitral regurgitation (MR) is the most common valvular lesion. Untreated, severe MR has a poor prognosis, with a 5-year mortality rate of up to 50%. Surgical repair of symptomatic, severe primary MR has been demonstrated to improve survival. The aim of this review is to assess the early outcomes of newly developed transcatheter mitral valve implantation technologies for the treatment of secondary native valve disease. Furthermore, the outcomes of patients receiving transcatheter treatment of regurgitant failure of surgically repaired or replaced mitral valve has also been addressed.

Methods

A systematic review of twenty-five studies assessing the outcomes of patients undergoing transcatheter mitral valve implantation for native mitral regurgitation or failed prior surgical repair or bioprosthetic replacement was carried out.

Results

The outcomes of 112 patients undergoing transcatheter mitral valve replacement for secondary mitral regurgitation using six different valve systems were assessed. There were 15 early deaths and 24 deaths over the follow-up period. The outcomes of 44 patients undergoing transcatheter valve-in-valve replacement were assessed with an overall mortality of ten patients. There were 20 patients included who had valve-in-ring transcatheter mitral replacement for previous failed repair. The total mortality was five patients during the follow-up period.

Conclusions

Transcatheter mitral valve implantation represents a new evolution in management of valvular disease and affords management options to patients who historically may not have been offered treatment. Early results have demonstrated some promise and improvements in technology, imaging modalities and patient selection will surely result in a reliable and durable valve.

Transcatheter Mitral Valve Planning and the Neo-LVOT: Utilization of Virtual Simulation Models and 3D Printing

PURPOSE OF REVIEW

Transcatheter mitral valve replacement (TMVR) is an emerging alternative for patients with severe mitral valve regurgitation who are considered at high risk for conventional surgical options. The early clinical experience with TMVR has shown that pre-procedural planning with computed tomography (CT) is needed to mitigate the risk of potentially lethal procedural complications such as left ventricular outflow tract (LVOT) obstruction. The goal of this review is to provide an overview of key concepts relating to TMVR pre-procedural planning, with particular emphasis on imaging-based methods for predicting TMVR-related LVOT obstruction.

RECENT FINDINGS

Risk of LVOT obstruction can be assessed with CT-based pre-procedural planning by using virtual device simulations to estimate the residual 'neo-LVOT' cross-sectional area which remains after device implantation. A neo-LVOT area of less than 2 cm² is currently thought to increase the risk of obstruction; however, additional studies are needed to further validate this cutoff value. Three-dimensional printing and personalized computational simulations are also emerging as valuable tools which may offer insights not readily confered by conventional two-dimensional image analysis. The simulated neo-LVOT should be routinely assessed on pre-procedural CT when evaluating anatomical suitability for TMVR.

Transcatheter mitral valve implantation for degenerated mitral bioprostheses or failed surgical annuloplasty rings: A systematic review and meta-analysis

BACKGROUND

Transcatheter mitral valve-in-valve (TMVIV) and valve-in-ring (TMVIR) implantation for degenerated mitral bioprostheses and failed annuloplasty rings have recently emerged as treatment options for patients deemed unsuitable for repeat surgery.

METHODS

A systematic literature review was conducted to summarize the data regarding the baseline characteristics and clinical outcomes of patients undergoing TMVIV and TMVIR procedures.

RESULTS

A total of 245 patients (172 patients who underwent TMVIV surgery and 73 patients who underwent TMVIR surgery) were included in the study; 93.5% of patients experienced successful TMVIV or TMVIR implantation. The mortality rates at discharge, 30 days, and 6 months were 5.7%, 8.1%, and 23.4%, respectively. The transapical (TA) access route was used in most procedures (55.2%). The TA and transseptal (TS) access routes resulted in similar outcomes. No significant differences were observed in the short-term outcomes between the patients who developed mitral stenosis versus mitral regurgitation as the mode of failure.

CONCLUSIONS

TMVIV and TMVIR implantation for degenerated mitral bioprostheses and failed annuloplasty rings are safe and effective. Both procedures, via TA or TS access, can result in excellent short-term clinical outcomes in patients with mitral stenosis or regurgitation, but long-term follow-up data are currently lacking to determine the durability of these procedures.

Transseptal Transcatheter Mitral Valve Replacement for Post-Surgical Mitral Failures

Post-surgical deterioration of mitral valve repairs or replacements may present a clinical dilemma due to the high-risk nature of repeat surgery. Recent advances in transcatheter techniques and surgery have enabled the implantation of balloon-expandable valves in the mitral position when surgical rings and valves are present. Valves may be implanted either via transseptal or transapical access, with a reported success rate between 88-100 %.

Degenerative Mitral Stenosis: From Pathophysiology to Challenging Interventional Treatment

Mitral stenosis (MS) is characterized by obstruction of left ventricular inflow as a result of narrowing of the mitral valve orifice. Although its prevalence has declined over the last decade, especially in developed countries, it remains an important cause of morbidity and mortality.  The most often cause of MS worldwide is still postrheumatic mitral valve disease. However, in developed countries, degenerative or calcific changes cause MS in a siginificant proportion of patients. Although the range of treatment for mitral valve disease has grown over the years in parallel with transcatheter therapies for aortic valve disease, these improvements in mitral valve disease therapy have experienced slower development. This is mainly due to the more complex anatomy of the mitral valve and entire mitral apparatus, and the interplay of the mitral valve with the left ventricle which hinders the development of effective implantable mitral valve devices. This is especially the case with degenerative MS where percutaneous or surgical comissurotomy is rarely employed due to the presence of extensive annular calcification and at the base of leaflets, without associated commissural fusion. However, the last few years have witnessed innovations in transcatheter interventional procedures for degenerative MS which consequently hinted that in the future, transcatheter mitral valve replacement could be the treatment of choice for these patients.

Impact of failed mitral valve repair on hospital outcome of redo mitral valve procedures

OBJECTIVES

The prognostic impact of failed mitral valve repair (FMR) on in-hospital outcome after redo mitral valve surgery has not been thoroughly investigated.

METHODS

Hospital outcomes after redo mitral valve surgery because of an FMR in patients from nine European centres were reported. Logistic regressions identified predictors of mortality in combined or isolated redo mitral valve operations. Hospital outcome was compared between propensity-matched cohorts with FMR and native mitral valves in the context of redo surgery and FMR versus failed prostheses.

RESULTS

A total of 246 patients with FMR yielded a 6.5% mortality rate at redo surgery. FMR per se did not impact mortality at multivariable analysis ( P = 0.64). A preoperative Global Initiative for Chronic Obstructive Lung Disease (GOLD) score ≥2 chronic obstructive lung disease (COPD) (OR 15.2, P < 0.01), left ventricular ejection fraction <30% (odds ratio (OR) 21.5, P = 0.005), major injury to cardiovascular structures at re-entry (OR 27.2, P < 0.01) or injury to patent left internal mammary artery-coronary artery bypass graft (OR 7.6, P = 0.03) predicted mortality in the whole FMR population. GOLD ≥ 2 COPD (OR 12.3, P = 0.049), age at surgery (OR 1.15 for each incremental year, P = 0.049) and cardiopulmonary bypass duration (OR 1.02, P = 0.022) predicted mortality in isolated redo mitral valve surgery for FMR. The fourth (> 68 years = 13.8% mortality) and the fifth quintiles of age (≥73.4 years = 14.8%) reported the highest mortality (OR 3.8 and 4.2 respectively, P = 0.002) in this subgroup. Propensity-matched cohorts of FMR and native mitral valves in the context of redo surgery showed no differences in terms of mortality ( P = 0.69) and major morbidity (acute myocardial infarction P = 0.31, stroke P = 0.65, acute kidney injury P  = 1.0), whereas more perioperative dialysis ( P = 0.04) and transfusions ( P = 0.02) were noted in propensity-matched failed prostheses compared to FMR.

CONCLUSIONS

A failed mitral repair does not impact hospital outcome of redo surgery. Given the role of severe left ventricular dysfunction and advanced age on hospital mortality rates, an early indication for redo surgery may improve outcome.

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

OPINION STATEMENT

Mitral regurgitation (MR) is frequent and associated with increased mortality and morbidity when severe. It may be caused by intrinsic valvular disease (primary MR) or ventricular deformation (secondary MR). Imaging has a critical role to document the severity, mechanism, and impact of MR on heart function as selected patients with MR may benefit from surgery whereas other will not. In patients planned for a surgical intervention, imaging is also important to select candidates for mitral valve (MV) repair over replacement and to predict surgical success. Although standard transthoracic echocardiography is the first-line modality to evaluate MR, newer imaging modalities like three-dimensional (3D) transesophageal echocardiography, stress echocardiography, cardiac magnetic resonance (CMR), and computed tomography (CT) are emerging and complementary tools for MR assessment. While some of these modalities can provide insight into MR severity, others will help to determine its mechanism. Understanding the advantages and limitations of each imaging modality is important to appreciate their respective role for MR assessment and help to resolve eventual discrepancies between different diagnostic methods. With the increasing use of transcatheter mitral procedures (repair or replacement) for high-surgical-risk patients, multimodality imaging has now become even more important to determine eligibility, preinterventional planning, and periprocedural guidance.

Single centre experience with transapical transcatheter mitral valve implantation

OBJECTIVES

A transcatheter heart valve technique can be used in failed mitral valve repairs with annuloplasty rings, deterioriated bioprostheses and in mitral annular calcification, all serving as 'docking stations' for balloon-expandable valves. Specially designed transcatheter mitral valve platforms are used in ongoing studies for native mitral valve regurgitation. We present our single centre experience with transcatheter mitral valve implantation-transapical approach procedures in eleven patients.

METHODS

Eleven patients were treated between 2011 and 2016. They had severe mitral regurgitation due to either failed repair annuloplasty rings (N = 6), failed bioprostheses (N = 2) or in the native valve (N = 3), all at high risk for open mitral valve surgery. Three different types of transcatheter valves were used: (1) the SAPIEN XT/SAPIEN 3, (2) the Lotus valve and (3) a Tendyne transcatheter mitral valve. Computed tomography reconstruction, echocardiography, 3D printing and bench tests were done in the preoperative evaluation and procedural planning. Transapical approach access was performed via a left minithoracotomy.

RESULTS

Implantation success was 100% with no left ventricular outflow tract obstruction. Good haemodynamics and improved New York Heart Association class were demonstrated in all patients. One patient died before 30 days due to sepsis. One patient had a valve thrombosis when switching from Coumadin to new oral anticoagulant and had a second valve implanted into the first one as a 'valve-in-valve' procedure.

CONCLUSIONS

The transapical approach is a safe and straight forward procedure for accessing the mitral valve. 'Transcatheter aortic valve implantation' prostheses may be used in redo surgery due to an already sufficient 'docking station'. These specially designed new prostheses may be beneficial for addressing mitral valve regurgitation, but are still under evaluation. Anticoagulation is mandatory.

Intentional Percutaneous Laceration of the Anterior Mitral Leaflet to Prevent Outflow Obstruction During Transcatheter Mitral Valve Replacement: First-in-Human Experience

OBJECTIVES

This study sought to use a new catheter technique to split the anterior mitral valve leaflet (AML) and prevent iatrogenic left ventricular outflow tract (LVOT) obstruction immediately before transcatheter mitral valve replacement (TMVR).

BACKGROUND

LVOT obstruction is a life-threatening complication of TMVR, caused by septal displacement of the AML.

METHODS

The procedure was used in patients with severe mitral valve disease and prohibitive surgical risk. Patients either had prior surgical mitral valve ring (n = 3) or band annuloplasty (n = 1) or mitral annular calcification with stenosis (n = 1). Iatrogenic LVOT obstruction or transcatheter heart valve dysfunction was predicted in all based on echocardiography and computed tomography. Transfemoral coronary guiding catheters directed an electrified guidewire across the center and base of the AML toward a snare in the left atrium. The externalized guidewire loop was then electrified to lacerate the AML along the centerline from base to tip, sparing chordae, immediately before transseptal TMVR.

RESULTS

Five patients with prohibitive risk of LVOT obstruction or transcatheter heart valve dysfunction from TMVR successfully underwent LAMPOON, with longitudinal splitting of the A2 scallop of the AML, before valve implantation. Multiplane computed tomography modeling predicted hemodynamic collapse from TMVR assuming an intact AML. However, critical LVOT gradients were not seen following LAMPOON and TMVR. Doppler blood flow was seen across transcatheter heart valve struts that encroached the LVOT, because the AML was split. Transcatheter heart valve function was unimpeded.

CONCLUSIONS

This novel catheter technique, which resembles surgical chord-sparing AML resection, may enable TMVR in patients with prohibitive risk of LVOT obstruction or transcatheter heart valve dysfunction.

Cardiac Computed Tomography and Magnetic Resonance Imaging in the Evaluation of Mitral and Tricuspid Valve Disease

Transcatheter interventions to treat mitral and tricuspid valve disease are becoming increasingly available because of the growing number of elderly patients with significant comorbidities or high operative risk. Thorough clinical and imaging evaluation in these patients is essential. The latter involves both characterization of the mechanism and severity of valvular disease as well as determining the hemodynamic consequences and extent of ventricular remodeling, which is an important predictor of future outcomes. Moreover, an assessment of the suitability and risk of complications associated with device-specific therapies is also an important component of the preprocedural evaluation in this cohort. Although echocardiography including 2-dimensional and 3-dimensional methods has an important role in the initial assessment and procedural guidance, cross-sectional imaging, including both computed tomographic imagning and cardiac magnetic resonance imaging, is increasingly being integrated into the evaluation of mitral and tricuspid valve disease. In this review, we discuss the role of cross-sectional imaging in mitral and tricuspid valve disease, primarily valvular regurgitation assessment, with an emphasis on the preprocedural evaluation and implications for transcatheter interventions.

Transcaval Access and Closure for Transcatheter Aortic Valve Replacement: A Prospective Investigation

BACKGROUND

Transcaval access may enable fully percutaneous transcatheter aortic valve replacement (TAVR) without the hazards and discomfort of transthoracic (transapical or transaortic) access.

OBJECTIVES

The authors performed a prospective, independently adjudicated, multicenter, single-arm trial of transcaval access for TAVR in patients who were ineligible for femoral artery access and had high or prohibitive risk of complications from transthoracic access.

METHODS

A total of 100 patients underwent attempted percutaneous transcaval access to the abdominal aorta by electrifying a caval guidewire and advancing it into a pre-positioned aortic snare. After exchanging for a rigid guidewire, conventional TAVR was performed through transcaval introducer sheaths. Transcaval access ports were closed with nitinol cardiac occluders. A core laboratory analyzed pre-discharge and 30-day abdominal computed tomograms. The Society of Thoracic Surgeons predicted risk of mortality was 9.6 ± 6.3%.

RESULTS

Transcaval access was successful in 99 of 100 patients. Device success (access and closure with a nitinol cardiac occluder without death or emergency surgical rescue) occurred 98 of 99 patients; 1 subject had closure with a covered stent. Inpatient survival was 96%, and 30-day survival was 92%. Second Valve Academic Research Consortium (VARC-2) life-threatening bleeding and modified VARC-2 major vascular complications possibly related to transcaval access were 7% and 13%, respectively. Median length of stay was 4 days (range 2 to 6 days). There were no vascular complications after discharge.

CONCLUSIONS

Transcaval access enabled TAVR in patients who were not good candidates for transthoracic access. Bleeding and vascular complications, using permeable nitinol cardiac occluders to close the access ports, were common but acceptable in this high-risk cohort. Transcaval access should be investigated in patients who are eligible for transthoracic access. Purpose-built closure devices are in development that may simplify the procedure and reduce bleeding. (Transcaval Access for Transcatheter Aortic Valve Replacement in People With No Good Options for Aortic Access; NCT02280824).

First-in-man transcatheter mitral valve-in-ring implantation with a repositionable and retrievable aortic valve prosthesis

AIMS

Transcatheter interventions with balloon-expandable valves have been shown to be efficacious for the treatment of mitral annuloplasty failure but are limited by the fact that there is no opportunity for post-implantation adjustment. The aim of this study was to assess the safety and efficacy of the fully repositionable and retrievable Direct Flow Medical (DFM) valve for the treatment of mitral annuloplasty failure.

METHODS AND RESULTS

Patients who underwent transcatheter mitral valve-in-ring (VIR) implantation of a DFM valve for failed mitral annuloplasty deemed high risk for redo surgery were included at four institutions. Eight patients underwent transcatheter mitral VIR procedures with implantation of the DFM valve. The DFM prosthesis was successfully positioned in all patients. Two patients required retrieval of the device due to a suboptimal result, and a further patient required repositioning of the valve with an ultimately successful implantation. During the 30-day follow-up period, two patients died for reasons unrelated to the valve implantation. The four patients with successful implantation had normal valve function associated with a significant improvement in their functional status.

CONCLUSIONS

For the first time, we demonstrate the safety, efficacy and advantages of using the DFM prosthesis for the treatment of mitral annuloplasty failure.

Transcatheter Mitral Valve-in-Valve Therapy

Valve-in-valve and valve-in-ring transcatheter mitral valve replacement can be used in for the treatment of inoperable patients with failing mitral surgical bioprosthesis or valve repairs. Preprocedural multi-image evaluation by a heart team must include transthoracic echocardiogram, transesophageal echocardiogram, and cardiac computed tomography angiography (CTA). CTA is used to determine access site (transapical, transseptal, or transatrial), transcatheter valve size, and landing zone. Though complications can occur (ie, valve embolization, bleeding, or vascular complications), this less invasive procedure has a reported success rate of 70% to 100% and is now increasingly used.