Factors influencing left ventricular outflow tract obstruction following a mitral valve-in-valve or valve-in-ring procedure, part 1

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.

Transseptal Balloon-Assisted Translocation of Mitral Leaflet for Mitral Calcification: A First in Human Experience

We present a first in human experience of transseptal balloon-assisted translocation of a mitral anterior leaflet (BATMAN) to facilitate transcatheter mitral valve replacement in a patient with severe mitral annular calcification who was at high risk of left ventricular outflow tract obstruction.

Transcatheter Treatment Options for Functional Mitral Regurgitation: Which Device for Which Patients?

Mitral regurgitation is the most common valvular disease in the developed world, with approximately 24.2 million people being affected worldwide and a higher prevalence in older age groups. Surgical correction of degenerative mitral regurgitation is the standard of care and can restore cardiac function and provide a lasting result, especially when the mitral valve can be repaired. Secondary mitral regurgitation, or functional mitral regurgitation (FMR), describes atrial or ventricular factors leading to poor coaptation of an otherwise non-diseased valve. For FMR, traditional surgery has not produced the same level of benefit. Transcatheter mitral repair and replacement techniques that mimic surgical correction are under investigation. Transcatheter edge-to-edge repair is the only approved catheter-based therapy for FMR in the US. Here, the transcatheter treatment options for FMR are reviewed.

Standardization and validation of neoLVOT assessment using three-dimensional trans-esophageal echocardiography before trans-catheter mitral valve replacement

BACKGROUND

Trans-catheter mitral valve replacement (TMVR) procedures had emerged as an alternative solution for patients who are at high risk for mitral valve surgery. Although cardiac computed tomography (CT) remains the standard method for procedural planning, there is no full agreement on the best systolic phase for quantitation of the neoLVOT. Furthermore, a new three-dimensional trans-esophageal echocardiography (3DTEE) based software was developed to serve as filter and or an alternative for patients who cannot have CT due to any contraindication.

AIM

To determine the systolic phase of the cardiac cycle that shows the narrowest NeoLVOT area in order to standardize the way of using these software and then to validate the 3DTEE-based software against the CT-based one as a gold standard, in mitral valve annulus (MA) and NeoLVOT assessment.

METHODS

A single center, observational, retrospective study. Initially, a sample of 20 patients (age 62 ± 4 years, 70% men) had CT-based analysis at mid-diastole (80%), early-systole (10%), mid-systole (20%), late-systole (30%-40%), in order to detect the best systolic phase at which the neoLVOT area is the narrowest after TMVR. Then, the end systolic phase was standardized for the analysis of 49 patients (age 57 ± 6 years, 60% men), using both the commercially available CT-based software and the newly available 3DTEE-based software (3mensio Structural Heart, Pie Medical Imaging, The Netherlands). The 3DTEE derived parameters were compared with the gold standard CT-based measurements.

RESULTS

The neoLVOT area was significantly narrower at end-systole (224 ± 62 mm2), compared to early-systole (299 ± 70 mm2) and mid-systole (261 ± 75 mm2), (p = .005). Excellent correlation was found between 3DTEE and CT measurements for MA AP diameter (r = .96), IC diameter (r = .92), MA area (r = .96), MA perimeter (r = .94) and NeoLVOT area (r = .96), (all p-values < .0001). Virtual valve sizing was based on annulus measurement and was identical between CT and 3DTEE. Interobserver and intraobserver agreements were excellent for all the measurements with ICCs > .80.

CONCLUSIONS

End-systole is the phase that shows the narrowest neoLVOT and hence should be the standard phase used during the analysis. The 3DTEE based analysis using this new software is reliable compared to the CT-based analysis and can be serve as an alternative analysis tool in patients who cannot have CT for any clinical contraindication or as a screening test and/or filter for all patients before proceeding to a detailed CT scan.

Valve-in-valve/valve-in-ring transcatheter mitral valve implantation vs. redo surgical mitral valve replacement for patients with failed bioprosthetic valves or annuloplasty rings: A systematic review and meta-analysis

Background

Valve-in-valve (ViV)/valve-in-ring (ViR) transcatheter mitral valve implantation (TMVI) is a less invasive alternative to redo surgical mitral valve replacement (SMVR). To further verify its feasibility, we aimed to appraise early clinical outcomes after either ViV/ViR TMVI or redo SMVR for failed bioprosthetic valves or annuloplasty rings, as a comparison of long-term follow-up results are not available for these procedures.

Methods

We systematically searched PubMed, Cochrane Controlled Trials Register, EMBASE, and Web of Science to identify studies that compared ViV/ViR TMVI and redo SMVR. Fixed- and random-effects meta-analyses were used to compare the early clinical results between these two groups.

Results

A total of 3,890 studies published from 2015 to 2022 were searched, and ten articles comprising 7,643 patients (ViV/ViR TMVI, 1,719 patients; redo SMVR, 5,924 patients) were included. In this meta-analysis, ViV/ViR TMVI significantly improved in-hospital mortality (fixed-effects model: odds ratio [OR], 0.72; 95% confidence interval [CI], 0.57-0.92; P = 0.008) and for the matched populations (fixed-effects model: OR, 0.42; 95% CI, 0.29-0.61; P < 0.00001). ViV/ViR TMVI also outperformed redo SMVR in 30-day mortality and in rates of early postoperative complications. ViV/ViR TMVI resulted in less time spent in the ICU and hospital, whereas it showed no significant difference in one-year mortality. A lack of comparison of long-term clinical outcomes and postoperative echocardiographic results are important limitations of our results.

Conclusions

ViV/ViR TMVI is a reliable alternative to redo SMVR for failed bioprosthetic valves or annuloplasty rings as a result of lower in-hospital mortality, higher 30-day survival, and lower early postoperative complication rates, although there is no significant difference in 1-year mortality.

Role of Cardiac Computed Tomography in Planning Transcatheter Mitral Valve Replacement (TMVR)

PURPOSE OF REVIEW

Transcatheter mitral valve replacement (TMVR) is an evolving and rapidly expanding field within structural interventions, offering renewed treatment options for patients with high-risk mitral valve disease. We aim to highlight and illustrate the importance of cardiac CT in the planning of TMVR.

RECENT FINDINGS

As TMVR has evolved, so has the specific nuances of cardiac CT planning, we now understand the importance of accurate annular sizing and valve simulation to predict complications such as neo-LVOT obstruction and paravalvular leak (PVL). More so than any other modality, cardiac CT remains instrumental in accurately planning TVMR from feasibility, device sizing, access, and fluoroscopic angles. Cardiac CT remains the key modality in TMVR evaluation, often the first step in determining patient eligibility through comprehensive procedural planning as well as informing potential outcomes and prognosis. In this review, we discuss the critical role of cardiac computed tomography (CT) and the specific considerations involved in TMVR.

Mitral Regurgitation in the High-Risk Patient: Integrating an Expanding Armamentarium of Transcatheter Devices Into the Treatment Algorithm

Over the last decade, multiple transcatheter mitral valve repair and replacement strategies have emerged, yet there is only 1 US Food and Drug Administration approved device, the MitraClip (Abbott Vascular, Inc., Santa Clara, CA). Current guidelines support the use of the MitraClip in high or prohibitive surgical risk patients, but there are many patients that are not anatomically suited for the device. This review article discusses the approach to degenerative and functional mitral regurgitation in the high-prohibitive risk patient, how to choose transcatheter treatment options (both approved and investigational), and potential management for therapy failure.

Role of computed tomography in transcatheter replacement of 'other valves': a comprehensive review of preprocedural imaging

Transcatheter procedures for heart valve repair or replacement represent a valid alternative for treating patients who are inoperable or at a high risk for open-heart surgery. The transcatheter approach has become predominant over surgical intervention for aortic valve disease, but it is also increasingly utilized for diseases of the 'other valves', that is the mitral and, to a lesser extent, tricuspid and pulmonary valve. Preprocedural imaging is essential for planning the transcatheter intervention and computed tomography has become the main imaging modality by providing information that can guide the type of treatment and choice of device as well as predict outcome and prevent complications. In particular, preprocedural computed tomography is useful for providing anatomic details and simulating the effects of device implantation using 3D models. Transcatheter mitral valve replacement is indicated for the treatment of mitral regurgitation, either primary or secondary, and computed tomography is crucial for the success of the procedure. It allows evaluating the mitral valve apparatus, the surrounding structures and the left heart chambers, identifying the best access route and the landing zone and myocardial shelf, and predicting obstruction of the left ventricular outflow tract, which is the most frequent postprocedural complication. Tricuspid valve regurgitation with or without stenosis and pulmonary valve stenosis and regurgitation can also be treated using a transcatheter approach. Computer tomography provides information on the tricuspid and pulmonary valve apparatus, the structures that are spatially related to it and may be affected by the procedure, the right heart chambers and the right ventricular outflow tract.

Mitral Valve Annuloplasty Failure and Percutaneous Treatment Options

PURPOSE OF REVIEW

Mitral valve repair is a common surgical procedure for both primary and secondary mitral regurgitation. With operations performed earlier in disease progression and increased patient longevity, the need for a repeat intervention is not infrequent. With the associated risks of reoperation and patient comorbidities, percutaneous techniques for acute or delayed failure after ring annuloplasty are emerging.

RECENT FINDINGS

Current commercially available devices, used in "off-label" ways, such as the MitraClip, may be effective in repairing recurrent mitral regurgitation after annuloplasty. Similarly, a valve-in-ring transcatheter mitral valve replacement can be considered in patients at high risk for surgical reoperation. These procedures are not without risk, for example, resultant mitral stenosis in the setting of edge-to-edge repair or left ventricular outflow tract (LVOT) obstruction with valve-in-ring transcatheter mitral valve replacement. Newer devices are emerging to permit more options for this subset of patients, which include transcatheter valves that are specifically designed for the mitral position. Undoubtedly, surgical reoperation has increased risk as compared to primary operation. Though percutaneous options are evolving, use in this patient population is currently limited to "off-label" use and is also associated with procedural complexities and risk. It is prudent for cardiologists, surgeons, and anesthesiologists to weigh risks, benefits, and limitations when considering patients for surgical reoperation, percutaneous repair, or transcatheter replacement after failed mitral annuloplasty.

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.

Hemolysis After Transcatheter Mitral Valve Implantation Resolved by Valve Retensioning

Transcatheter mitral valve implantation is an emerging technology for the treatment of inoperable or high-risk patients with symptomatic severe mitral regurgitation. Known technical issues are obstruction of the left ventricular outflow tract, paravalvular leakage, and hemolysis. We report a case of valve retensioning successfully resolving paravalvular leakage and hemolysis. (Level of Difficulty: Intermediate.).

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.

Effects of Transapical Transcatheter Mitral Valve Implantation

Purpose: In this study, transapical transcatheter mitral valve-in-valve implantation (TAMVI) was compared with surgical redo mitral valve replacement (SRMVR) in terms of clinical outcomes. Methods: We retrospectively identified patients with degenerated mitral bioprosthesis or failed annuloplasty rings who underwent redo SRMVR or TAMVI at our medical center. Clinical outcomes were based on echocardiography results. Results: We retrospectively identified patients with symptomatic mitral bioprosthetic valve dysfunction (n = 58) and failed annuloplasty rings (n = 14) who underwent redo SRMVR (n = 36) or TAMVI (n = 36). The Society of Thoracic Surgeons Predicted Risk of Mortality scores were higher in the TAMVI group (median: 9.52) than in the SRMVR group (median: 5.59) (p-value = 0.02). TAMVI patients were more severe in New York Heart Association (p-value = 0.04). The total procedure time (skin to skin) and length of stay after procedures were significantly shorter in the TAMVI group, and no significant difference in mortality was noted after adjustment for confounding factors (p-value = 0.11). The overall mean mitral valve pressure gradient was lower in the TAMVI group than in the SRMVR group at 24 months (p < 0.01). Both groups presented a decrease in the severity of mitral and tricuspid regurgitation at 3-24 months. Conclusions: In conclusion, the statistical analysis is still not robust enough to make a claim that TAMVI is an appropriate alternative. The outcome of the patient appears only to be related to the patient's pre-operative STS score. Additional multi-center, longitudinal studies are warranted to adequately assess the effect of TAMVI.

Double transcatheter balloon-expandable valve implantation for severe valve dysfunction in high-risk patients: initial experience

OBJECTIVES

Concomitant valvular heart valve disease is a frequent finding, with higher morbidity and mortality among patients undergoing redo surgical procedures. Our goal was to report our initial experience with combined transcatheter Inovare bioprosthesis implants for severe valve dysfunction.

METHODS

Among 300 transcatheter procedures, a total of 6 patients had concurrent simultaneous transcatheter bioprosthesis implants for severe mitral bioprosthesis failure (valve-in-valve), with a second valve procedure that included native aortic (n = 2) or degenerated bioprostheses in the aortic position (n = 4). During the procedures, all patients were treated with a balloon-expandable Inovare transcatheter valve, using the transapical approach.

RESULTS

Patients were highly symptomatic [New York Heart Association (NYHA) functional class IV: 100%], with a mean age of 62 ± 5 years, yielding a mean European System for Cardiac Operative Risk II (EuroSCORE II) of 24.0 ± 10.1%. There was a mean of 1.6 ± 0.4 prior valve operations/patient, with a median time from prior mitral bioprosthesis surgery of 13.0 (9.2-20.0) years. Device success was 100% according to the Mitral Valve Academic Research Consortium and the Valve Academic Research Consortium-2 criteria. During the hospital stay, only 1 patient required dialysis, and the median intensive care unit and hospital lengths of stay were 5.0 (3.2-6.7) days and 16.0 (12.2-21.2) days, respectively. No deaths occurred at 30 days; at a median follow-up of 287 (194-437) days, 1 patient died of a non-cardiac cause and the rest of patients were in NYHA functional class I or II, with normofunctioning bioprostheses.

CONCLUSIONS

Transcatheter double valve interventions using the Inovare bioprosthesis in this initial series were shown to be a reasonable alternative to redo surgical operations. The short- and mid-term clinical and echocardiographic outcomes demonstrate promising results, although future studies with a larger number of patients and longer follow-up are warranted.

Role of Cardiac CT in Pre-Procedure Planning for Transcatheter Mitral Valve Replacement

OBJECTIVES

This study sought to evaluate cardiac computed tomography (CCT) findings and their clinical impact among patients being considered for transcatheter mitral valve replacement (TMVR).

BACKGROUND

CCT is used to evaluate whether patients are candidates for TMVR, but limited data exist on the yield of such tests.

METHODS

Patients referred for pre-procedural CCT for TMVR planning in the context of failing mitral bioprosthetic valves, annuloplasty rings, and severe native valve disease with annular calcification were included in this study. CCT findings were analyzed to evaluate for suitability for TMVR. In the subset of patients who underwent TMVR, echocardiographic and procedural characteristics were recorded.

RESULTS

Among 80 patients who underwent pre-procedural CCT, the mean age was 71.8 ± 11.4 years, 60% were women, and the mean Society of Thoracic Surgeon score was 9.4 ± 6.7. Most cases were referred for valve-in-native annular calcification planning (n = 43), followed by valve-in-valve (n = 29), and valve-in-ring procedures (n = 8). A total of 51 (64%) patients did not undergo TMVR, 37 of whom had high-risk features identified on CCT. The most common reason for exclusion was related to large annular size, followed by heightened risk of left ventricular outflow tract (LVOT) obstruction. Among 29 patients (36%) who underwent TMVR, the 30-day mortality rate was 17%. Five patients experienced LVOT obstruction, 4 of whom were predicted by CCT. Following TMVR, 5 patients had at least moderate peri-valvular regurgitation.

CONCLUSIONS

A minority of patients referred for TMVR planning ultimately undergo the procedure. CCT identifies unsuitable anatomy and leads to exclusion in a significant number of cases.

MitraClip After Failed Surgical Mitral Valve Repair-An International Multicenter Study

Background Recurrence of mitral regurgitation (MR) after surgical mitral valve repair (SMVR) varies and may require reoperation. Redo mitral valve surgery can be technically challenging and is associated with increased risk of mortality and morbidity. We aimed to assess the feasibility and safety of MitraClip as a treatment strategy after failed SMVR and identify procedure modifications to overcome technical challenges. Methods and Results This international multicenter observational retrospective study collected information for all patients from 16 high-volume hospitals who were treated with MitraClip after failed SMVR from October 29, 2009, until August 1, 2017. Data were anonymously collected. Technical and device success were recorded per modified Mitral Valve Academic Research Consortium criteria. Overall, 104 consecutive patients were included. Median Society of Thoracic Surgeons score was 4.5% and median age was 73 years. At baseline, the majority of patients (82%) were in New York Heart Association class ≥III and MR was moderate or higher in 86% of patients. The cause of MR pre-SMVR was degenerative in 50%, functional in 35%, mixed in 8%, and missing/unknown in 8% of patients. The median time between SMVR and MitraClip was 5.3 (1.9-9.7) years. Technical and device success were 90% and 89%, respectively. Additional/modified imaging was applied in 21% of cases. An MR reduction of ≥1 grade was achieved in 94% of patients and residual MR was moderate or less in 90% of patients. In-hospital all-cause mortality was 2%, and 86% of patients were in New York Heart Association class ≤II. Conclusions MitraClip is a safe and less invasive treatment option for patients with recurrent MR after failed SMVR. Additional/modified imaging may help overcome technical challenges during leaflet grasping.

Computed Tomography-Derived 3D Modeling to Guide Sizing and Planning of Transcatheter Mitral Valve Interventions

A plethora of catheter-based strategies have been developed to treat mitral valve disease. Evolving 3-dimensional (3D) multidetector computed tomography (MDCT) technology can accurately reconstruct the mitral valve by means of 3-dimensional computational modeling (3DCM) to allow virtual implantation of catheter-based devices. 3D printing complements computational modeling and offers implanting physician teams the opportunity to evaluate devices in life-size replicas of patient-specific cardiac anatomy. MDCT-derived 3D computational and 3D-printed modeling provides unprecedented insights to facilitate hands-on procedural planning, device training, and retrospective procedural evaluation. This overview summarizes current concepts and provides insight into the application of MDCT-derived 3DCM and 3D printing for the planning of transcatheter mitral valve replacement and closure of paravalvular leaks. Additionally, future directions in the development of 3DCM will be discussed.

Multimodality Cardiac Imaging for Procedural Planning and Guidance of Transcatheter Mitral Valve Replacement and Mitral Paravalvular Leak Closure

Transcatheter mitral valve interventions are an evolving and growing field in which multimodality cardiac imaging is essential for diagnosis, procedural planning, and intraprocedural guidance. Currently, transcatheter mitral valve-in-valve with a balloon-expandable valve is the only form of transcatheter mitral valve replacement (TMVR) approved by the FDA, but valve-in-ring and valve-in-mitral annular calcification interventions are increasingly being performed. Additionally, there are several devices under investigation for implantation in a native annulus. Paravalvular leak (PVL) is a known complication of surgical or transcatheter valve implantation, where regurgitant flow occurs between the prosthetic sewing ring and the native mitral annulus. We sought to describe the role and applications of multimodality cardiac imaging for TMVR, and PVL closure, including the use of Cardiovascular Computed Tomography Angiography and 3-Dimensional Transesophageal Echocardiography for diagnosis, prosthetic valve evaluation, pre-procedural planning, and intraprocedural guidance, as well as evolving technologies such as fusion imaging and 3D printing.

Mitral valve-in-valve and valve-in-ring: tips, tricks, and outcomes

Transcatheter aortic valve implantation is now a mainstay of treatment in patients with aortic stenosis who are considered intermediate, high and prohibitive risk for surgery. Extended use of this innovative platform in treating other conditions has led to its approval in treating degenerated aortic bioprosthesis. Similarly, use of transcatheter devices in treating degenerated mitral bioprosthesis and failed mitral valve repairs with annuloplasty rings has opened a potential alternative to surgery in these patients. Experience in mitral valve-in-valve (MVIV) and valve-in-ring (VIR), while still limited, is on the rise. Although similar in many ways to the aortic VIV, it is different with respect to patient selection, planning and procedural steps. Familiarity with the bioprosthetic properties and dimensions can help an operator choose an appropriate transcatheter device and deploy it in an ideal position. Due to greater variability in construction and properties, mitral rings have led to poorer results compared to mitral valve-in-valve. Understanding the properties of mitral rings is critical and has been simplified by us in a stepwise manner. We also describe steps in patient preparation and procedure, which should help operators in performing this procedure. Certain unique complications, such as left ventricular outflow tract obstruction and risk of embolization, are discussed with tips to address these issues. Once these steps are followed, the procedure can be performed with minimal risk and good outcome.

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.

Transapical mitral valve-in-valve procedure with elective venoarterial ECMO in a patient with severe kyphoscoliosis

Transcatheter mitral valve-in-valve replacement (TMVR) is a feasible alternative in high-risk patients requiring reoperation for failing mitral bioprosthesis. Such patients may present with hemodynamic instability or sudden complications, which may jeopardize the outcomes. We report a successful transapical TMVR in a patient, with severe kyphoscoliosis and on prolonged mechanical ventilation, with prophylactic extracorporeal membrane oxygenator support. This combined procedure may be helpful to reduce the complications of TMVR in critically ill subjects.

Utility of Three-Dimensional (3D) Modeling for Planning Structural Heart Interventions (with an Emphasis on Valvular Heart Disease)

PURPOSE OF REVIEW

Advanced imaging has played a vital role in the contemporary, rapid rise of structural heart interventions. 3D modeling and printing has emerged as one of the most recent imaging tools and the implementation of 3D modeling is expected to increase with further advances in imaging, print hardware, and materials.

RECENT FINDINGS

3D modeling can be used to educate patients and clinical teams, provide ex vivo procedural simulation, and improve outcomes. Intra-procedural success rates may be improved, and post-procedural complications can be predicted more robustly with appropriate application of 3D modeling. Recent advances in technology have increased the availability of this tool, such that there can be more ready adoption into a routine clinical workflow. Familiarity with 3D modeling and its current utilization and role in structural interventions will help inform how to approach and adapt this exciting new technology.

Imaging Guidance for Transcatheter Mitral Valve Intervention on Prosthetic Valves, Rings, and Annular Calcification

Catheter-based interventions to improve mitral valve function are dependent on anatomic and functional information provided by noninvasive imaging to plan, perform, and evaluate each intervention. In this review we highlight the importance of imaging guidance for catheter-based interventions on prosthetic mitral valves, surgical rings, and native valve annular calcification. Both repair and replacement procedures are discussed. We review the general features common to this collection of procedures and discuss specific imaging issues and concerns for each procedure. Figures and intraprocedural videos emphasize central messages using case examples.

Screening for transcatheter mitral valve replacement: a decision tree algorithm

AIMS

The high frequency of screening failure for anatomical reasons in patients with severe mitral valve regurgitation (MR) is a limiting factor in the screening process for transcatheter mitral valve replacement (TMVR). However, data on optimal patient selection are scarce. The present study aimed to develop a screening algorithm based on TMVR screening data.

METHODS AND RESULTS

A total of 195 screenings for six different TMVR devices were performed in 94 high-risk patients with severe MR. We compared baseline echocardiographic and multislice computed tomography (MSCT) parameters between the subgroups of patients accepted (N=33) and rejected for TMVR (N=61). Reasons for screening failure were assessed, and a decision tree algorithm was statistically derived. Reasons for screening failure were small LV dimensions (30.6%), small (7.5%) or large (22.5%) annular size, potential risk of LVOT obstruction (22.0%) or mitral annulus calcification (15.6%). A four-step decision tree algorithm to assess TMVR eligibility was developed resulting in an AUC of 0.80 (95% CI: 0.71, 0.89, p<0.0001).

CONCLUSIONS

This study presents the first screening algorithm to assess anatomical eligibility for TMVR in patients with severe MR, based on simple MSCT criteria. Given the high rate of TMVR screening failure, this algorithm may facilitate the identification of potential TMVR candidates.

Percutaneous Trans-septal Mitral Valve-in-Ring Implantation Using a Transcatheter Balloon-Expandable Transcatheter Heart Valve With Elective Intra-Procedural Artero-Venous ECMO in a Patient With Severely Reduced Left Ventricular Ejection Fraction

Percutaneous mitral valve-in-valve implantation is an emerging option in patients with surgical bioprosthesis failure or failing mitral annuloplasty and increased surgical risk. We present a case of transcatheter transvenous trans-septal mitral valve-in-ring (TMVinR) procedure, in a patient with severe left ventricular dysfunction and severe mitral regurgitation, after surgical mitral annuloplasty, managed with periprocedural mechanical circulatory support (MCS) with VA-ECMO.

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.

Case report of simultaneous transcatheter mitral valve-in-valve implantation and percutaneous closure of two paravalvular leaks

Background

Concomitant structural degeneration of surgical mitral bioprostheses and paravalvular leak (PVL) is rare but potentially fatal. Data pertaining to simultaneous transcatheter mitral valve implantation (TMVI) and percutaneous PVL closure are limited, and the optimal treatment strategy remains undetermined. We report a case of simultaneous TMVI and double percutaneous PVL closure in a patient with a degenerated bioprosthetic mitral valve and associated medial and lateral PVLs.

Case summary

A 75-year-old woman who underwent combined aortic (Edwards Perimount Magna 19 mm) and mitral (Edwards Perimount Magna 25 mm) surgical valve replacement 6 years ago was referred for treatment of new-onset orthopnoea and severely reduced exercise capacity. Transoesophageal echocardiography revealed severe mitral stenosis and concomitant moderate to severe mitral regurgitation, originating from two PVLs located medial and lateral from the surgical bioprosthesis. Due to high surgical risk, we performed successful transseptal mitral valve-in-valve (ViV) implantation combined with the closure of two PVLs during the same procedure.

Discussion

Although surgery should be considered as a first-line treatment in this setting, most patients have extremely high or prohibitive surgical risk inherent to repeat open heart surgery. Mitral ViV implantation appears a reasonable treatment option for patients with failed mitral bioprostheses. Furthermore, a recent study of percutaneous PVL closure showed no significant difference in long-term all-cause mortality compared with redo open-heart surgery. Simultaneous TMVI and percutaneous PVL closure appears feasible in selected high-risk patients.

Transcatheter Mitral Valve Replacement in Patients with Severe Mitral Annular Calcification

Mitral annular calcification (MAC) is a fibrous, degenerative calcification of the mitral valve. It is associated with endocarditis, coronary artery disease, valvular heart disease, and congestive heart failure. Patients with severe MAC associated with mitral valve disease are considered poor candidates for traditional surgery. The current available outcomes data of transcatheter mitral valve replacement (TMVR) in severe MAC were limited by high rates of serious complications and subsequent high short-term and midterm mortality. This review article describes the procedural complications, clinical outcomes, and optimal patient selection for TMVR in patients with severe MAC.

Anterior Leaflet Laceration to Prevent Ventricular Outflow Tract Obstruction During Transcatheter Mitral Valve Replacement

BACKGROUND

Left ventricular outflow tract (LVOT) obstruction is a leading cause of mortality and exclusion from transcatheter mitral valve replacement (TMVR). Intentional laceration of the anterior mitral valve leaflet to prevent LVOT obstruction (LAMPOON) is a transcatheter mimic of surgical chord-sparing leaflet resection.

OBJECTIVES

The purpose of this prospective multicenter trial was to study LAMPOON with transseptal (Edwards Lifesciences, Irvine, California) TMVR in annuloplasty rings or native mitral annular calcification (MAC).

METHODS

Subjects at high or extreme surgical risk and prohibitive risk of LVOT obstruction from TMVR were included. Eligibility was modified midtrial to exclude subjects with threatened LVOT obstruction from a Sapien 3 valve fabric skirt. The primary endpoint was procedure survival with successful LAMPOON, with successful TMVR, without reintervention, and with LVOT gradient <30 mm Hg ("optimal") or <50 mm Hg ("acceptable"). Secondary endpoints included 30-day mortality and major adverse cardiovascular events. There was universal source-data verification and independent monitoring. All endpoints were independently adjudicated. Central laboratories analyzed echocardiogram and CT images.

RESULTS

Between June 2017 and June 2018, 30 subjects were enrolled equally between the MAC and ring arms. LAMPOON traversal and midline laceration was successful in 100%. Procedure survival was 100%, and 30-day survival was 93%. Primary success was achieved in 73%, driven by additional procedures for paravalvular leak (10%) and high-skirt neo-LVOT gradients observed before a protocol amendment. There were no strokes.

CONCLUSIONS

LAMPOON was feasible in native and annuloplasty ring anatomies in patients who were otherwise ineligible for treatment, with acceptable safety. LAMPOON was effective in preventing LVOT obstruction from TMVR. Despite LAMPOON, TMVR using Sapien 3 in annuloplasty rings and MAC still exhibits important limitations. (NHLBI DIR LAMPOON Study: Intentional Laceration of the Anterior Mitral Leaflet to Prevent Left Ventricular Outflow Tract Obstruction During Transcatheter Mitral Valve Implantation; NCT03015194).

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.

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.

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.

Left ventricular outflow obstruction predicts increase in systolic pressure gradients and blood residence time after transcatheter mitral valve replacement

Left ventricular outflow tract (LVOT) obstruction is a relatively common consequence of transcatheter mitral valve replacement (TMVR). Although LVOT obstruction is associated with heart failure and adverse remodelling, its effects upon left ventricular hemodynamics remain poorly characterised. This study uses validated computational models to identify the LVOT obstruction degree that causes significant changes in ventricular hemodynamics after TMVR. Seven TMVR patients underwent personalised flow simulations based on pre-procedural imaging data. Different virtual valve configurations were simulated in each case, for a total of 32 simulations, and the resulting obstruction degree was correlated with pressure gradients and flow residence times. These simulations identified a threshold LVOT obstruction degree of 35%, beyond which significant deterioration of systolic function was observed. The mean increase from baseline (pre-TMVR) in the peak systolic pressure gradient rose from 5.7% to 30.1% above this threshold value. The average blood volume staying inside the ventricle for more than two cycles also increased from 4.4% to 57.5% for obstruction degrees above 35%, while the flow entering and leaving the ventricle within one cycle decreased by 13.9%. These results demonstrate the unique ability of modelling to predict the hemodynamic consequences of TMVR and to assist in the clinical decision-making process.