Transcatheter Mitral Valve Replacement: An Update on the Current Literature

Management of patients with mitral regurgitation ineligible for standard therapy undergoing TMVI screening

BACKGROUND

Transcatheter mitral valve implantation (TMVI) represents a novel treatment alternative for patients with severe mitral regurgitation (MR) considered ineligible for standard therapies. Data on the management of patients after TMVI screening are scarce.

AIMS

We aimed to investigate outcomes of patients with severe MR undergoing TMVI evaluation treated with either TMVI, bailout-transcatheter edge-to-edge repair (bailout-TEER) or medical therapy (MT).

METHODS

Between May 2016 and February 2021, 121 patients with MR considered ineligible for standard therapy were screened for TMVI. Outcomes were assessed for the subgroups of patients treated with TMVI, bailout-TEER and MT. The primary composite endpoint was all-cause death or heart failure hospitalisation after one year.

RESULTS

The subgroups of TMVI (N=38), bailout-TEER (N=28) and MT (N=44) differed significantly with regard to MR aetiology (secondary MR: TMVI 68.4%, bailout-TEER 39.3%, MT 38.6%, p=0.014) and left ventricular ejection fraction (TMVI 37.0% [31.4-51.2], bailout-TEER 48.0% [35.3-58.3], MT 54.5% [40.8-60.0], p<0.001). At discharge and after one year, MR was reduced to ≤mild residual MR in all patients undergoing TMVI, while ≥moderate residual MR was present in 25.9% and 20.0% of patients, respectively, after bailout-TEER, and in 100.0% of patients on MT at one year. The primary endpoint occurred in 72.2% of patients remaining on MT, in 51.6% of patients undergoing TMVI and in 40.2% of those receiving bailout-TEER.

CONCLUSIONS

In MR patients considered ineligible for standard therapy, TMVI provided acceptable clinical outcomes and MR elimination in the majority of patients. In screen-failed patients, bailout-TEER represented a reasonable alternative while MT was associated with poor outcomes.

Interventions for Congenital Atrioventricular Valve Dysfunction: JACC Focus Seminar

Innovation and creativity have led to tremendous advancements in the care and management of patients with congenital heart disease (CHD) that have resulted in considerably increased survival. Catheter-based interventions have contributed significantly to these advancements. However, catheter-based interventions for congenital lesions of the atrioventricular (AV) valves have been limited in scope and effectiveness mainly because of patient size and anatomical challenges. Thus, surgical repair and replacement for congenital AV valve lesions have remained the preferred therapy. However, the ongoing transcatheter heart valve revolution has led to techniques and technologies that are changing the landscape, particularly for adult CHD patients. Many devices for AV valve repair and replacement are being studied in adult patients without CHD, and translation of select practices to CHD patients has begun, with many more to come. Transcatheter AV valve interventions represent exciting opportunities for the growing numbers of adult CHD patients.

Sex-related differences in the trends and outcomes of trans-septal transcatheter mitral valve replacement: Insights from the National Readmissions Database

BACKGROUND

There is a paucity of data regarding the sex-related differences in the trends and outcomes of trans-septal transcatheter mitral valve replacement (TS-TMVR).

METHODS

The Nationwide Readmissions Database (2015-2018) was queried for admissions for TS-TMVR. Propensity matched analysis was conducted to compare outcomes with hospitalizations for TS-TMVR among women versus men. The main study outcome was in-hospital mortality.

RESULTS

Our final analysis included 2063 hospitalizations for TS-TMVR; of whom, 58.1% were women. The proportion of women among those undergoing TS-TMVR increased from 50% in 2015 to 60.2% in 2018 (P_trend  = 0.04). Compared with men, women undergoing TS-TMVR were slightly younger, and had a distinct profile of comorbidities. After matching, there was no significant difference in in-hospital mortality among women versus men undergoing TS-TMVR (7.8% vs. 6.1%, OR = 1.30; 95% CI: 0.79-2.13). Subgroup analyzes showed an interaction toward higher mortality with women versus men among patients with CKD (P_interaction  = 0.07). There were no significant differences between women and men in in-hospital complications or length of stay after TS-TMVR. Compared with men, women undergoing TS-TMVR were more likely to be discharged to a nursing facility (17.7% vs. 11.5%, p = 0.01) and had higher rates of 30-day readmissions (22.4% vs. 13.6%, p = 0.01).

CONCLUSION

This nationwide analysis showed an increase in the proportion of women among patients undergoing TS-TMVR during the study years. There were no differences in in-hospital mortality, in-hospital complications, or length of stay between both sexes following TS-TMVR. Women were more likely to be discharged to nursing facilities and had higher rates of readmission at 30 days even after propensity matching.

Left atrial geometry in an ovine ischemic mitral regurgitation model: implications for transcatheter mitral valve replacement devices with a left atrial anchoring mechanism

BACKGROUND

Transcatheter mitral valve replacement (TMVR) is a challenging, but promising minimally invasive treatment option for patients with mitral valve disease. Depending on the anchoring mechanism, complications such as mitral leaflet or chordal disruption, aortic valve disruption or left ventricular outflow tract obstruction may occur. Supra-annular devices only anchor at the left atrial (LA) level with a low risk of these complications. For development of transcatheter valves based on LA anchoring, animal feasibility studies are required. In this study we sought to describe LA systolic and diastolic geometry in an ovine ischemic mitral regurgitation (IMR) model using magnetic resonance imaging (MRI) and echocardiography in order to facilitate future research focusing on TMVR device development for (I)MR with LA anchoring mechanisms.

METHODS

A group of 10 adult male Dorsett sheep underwent a left lateral thoracotomy. Posterolateral myocardial infarction was created by ligation of the left circumflex coronary artery, the obtuse marginal and diagonal branches. MRI and echocardiography were performed at baseline and 8 weeks after myocardial infarction (MI).

RESULTS

Six animals survived to 8 weeks follow-up. All animals had grade 2 + or higher IMR 8 weeks post-MI. All LA geometric parameters did not change significantly 8 weeks post-MI compared to baseline. Diastolic and systolic interpapillary muscle distance increased significantly 8 weeks post-MI.

CONCLUSIONS

Systolic and diastolic LA geometry do not change significantly in the presence of grade 2 + or higher IMR 8 weeks post-MI. These findings help facilitate future tailored TMVR device development with LA anchoring mechanisms.

Transcatheter Mitral Valve Implantation Systematic Review: Focus on Transseptal Approach and Mitral Annulus Calcification

INTRODUCTION

This systematic review was performed to evaluate the results of transcatheter mitral valve implantation (TMVI) in the native mitral valve.

EVIDENCE ACQUISITION

Medline, EMBASE, and the Cochrane Central register were systematically searched for studies that reported results of TMVI in mitral valve regurgitation and/or stenosis and mitral annular calcification. To improve the sensitivity of the literature search, we performed citation chasing in Google Scholar, Scopus, and Web of Science.

EVIDENCE SYNTHESIS

Twelve studies reporting results of TMVI in mitral regurgitation were retrieved and included 347 patients. The transseptal approach represented 28% of cases. Secondary mitral regurgitation was the predominant indication in 63% of cases. Thirty-day mortality was 11% and was lowered with the transseptal approach (7%). Technical success was 92%. Surgical conversion was needed in 5% of patients. Only one patient presented moderate to severe mitral regurgitation. These hemodynamic results were sustainable up to one year of follow-up. Three series focused on results of TMVI in mitral annulus calcification including 167 patients. Only nine patients were treated with TMVI dedicated prosthesis. Eighty-seven patients had their prosthesis delivered through a transseptal approach. Mitral stenosis was present in 63% of cases. Thirty-day mortality was 24%, and none with TMVI prosthesis. Technical success was achieved in 71% of cases and was improved by using TMVI prosthesis (89%). The main complication was left ventricular outflow tract obstruction (20%). Post procedural moderate to severe mitral regurgitation was observed in 4% of cases.

CONCLUSION

TMVI seems to be feasible, achieving good technical success and predictable and durable MR reduction.

Atrial and ventricular flows across a transcatheter mitral valve

 

OBJECTIVES

The objective of this study was to evaluate the haemodynamic performance of transcatheter mitral valve replacement (TMVR) Implant with a focus on turbulence and washout adjacent to the ventricular surface of the leaflets. TMVR holds the promise of treating a large spectrum of mitral valve diseases. However, the haemodynamic performance and flow dynamics of such replacements are not fully understood.

METHODS

A tri-leaflet biopsrosthetic TMVR represented by Caisson implant of size 36A was implanted in the mitral position of a left heart simulator pulse duplicating system under physiological conditions. The 36A implant covers an anterior-posterior range of 26-32 mm and a commissure-to-commissure range of 30-36 mm. Transmitral pressure gradient, effective orifice area and regurgitant fraction were calculated. Particle image velocimetry was performed to evaluate turbulence in 2 perpendicular planes (Reynolds and viscous shear stresses, respectively). Additionally, dye experiments were performed to visualize washout.

RESULTS

Transmitral pressure gradient was 1.29 ± 0.27 mmHg and effective orifice area was 2.96 ± 0.28 cm2. Regurgitant fraction was 14.13 ± 0.08%. Total washout was 4.27 cardiac cycles. Largest viscous shear stress reaches 3.7 Pa and 2.4 Pa in ventricle and atrium, respectively. Reynolds shear stress in the atrial side was <10 Pa. In the ventricular side, the largest Reynolds shear stress reached ∼35 Pa.

CONCLUSIONS

TMVR leads to favourable haemodynamics with low degree of turbulence combined with fast washout around the leaflets indicating promising potential for freedom from blood damage potential and thrombosis corroborated by initial clinical studies as part of the valves's Early Feasibility Study.

Imaging the mitral valve: a primer for the interventional surgeon

Transcatheter mitral valve interventions (TMVI) have evolved over the past decade as alternatives to open surgical repair for the therapeutic management of patients with severe mitral regurgitation (MR). Concurrent with the development of these technologies, quality multi-modality cardiac imaging has become essential in patient selection and procedural guidance. The former involves assessments of the pathophysiologic mechanisms of regurgitation, valvular anatomy and morphology, as well as objective quantification of the severity of MR. Both transthoracic and transesophageal echocardiography (TEE) are crucial and serve as the gateway to diagnosis and management of mitral valvular disease. Along with multi-detector computed tomography (CT) and cardiac magnetic resonance imaging (CMR), echocardiography plays an important role for preprocedural planning and evaluation of the spatial relationships of the mitral valvular complex with the coronary sinus, circumflex coronary artery and left ventricular (LV) outflow tract. Procedures that target mitral leaflets (e.g., MitraClip, PASCAL) or annulus (e.g., Cardioband, Carillon), or provide chordal (e.g., NeoChord, Harpoon) or valvular replacement, tend to be guided by TEE and assisted by fluoroscopy. As newer devices become available and outcomes of TMVI improve, cardiac imaging will undoubtedly continue to play an essential role in the success of percutaneous mitral valve repair (MVr) and replacement. The interventional surgeon of the future must therefore have a thorough understanding of the various imaging modalities while synthesizing and integrating novel concepts (e.g., neo-LV outflow tract) as applicable to assessing valvular function and pathology.

Transcatheter Mitral Valve Replacement: Procedural Planning, Utility, and Applicability

Since the first native transcatheter mitral valve implantation in 2012, transcatheter mitral valve replacement (TMVR) has expanded its use to degenerated bioprostheses, failed annuloplasty ring repair, and mitral annular calcification. However, high-screen failure rates in trials have persisted due to predicted left ventricular outflow tract obstruction and unfavorable anatomy. Preprocedural planning in this patient population with multidetector computed tomography and transesophageal echocardiography is paramount to intraprocedural success. In patients with favorable left ventricular outflow tract anatomy who are not surgical candidates, the transseptal approach is preferred. In those who are surgical candidates, TMVR can be performed via a transapical or transatrial approach. Currently, a plethora of TMVR devices targeting the native mitral pathologies are undergoing clinical trials. Data have consistently shown the greatest benefit of this procedure in native mitral regurgitation and failed bioprostheses rather than failed annuloplasty rings or mitral annular calcification. With technological advancement and careful patient selection, this therapy will serve as a complement to surgical and TMV repair and will continue to expand to address MV diseases in a broader patient population.

Hemodynamics rounds: Hemodynamics of mitral valve interventions

Mitral valvulopathy presents as regurgitation, stenosis, or mixed disease and can occur in both native and prosthetic valves. Such disease develops in conjunction with pathophysiologic changes in the left atrium (LA) and drives changes in LA compliance, pressure, and thus clinical syndromes. With advances in the understanding and treatment of structural heart disease and in the setting of higher-risk patient populations, less-invasive transcatheter approaches have become increasingly commonplace in the treatment of mitral valve disease. Over time, transcatheter mitral valve interventions have evolved to include paravalvular leak closure, mitral valve repair, and mitral valve replacement. Parallel to this evolution, advances in invasive intracardiac pressure monitoring, particularly at the level of the LA, have also occurred. These advances emphasize the unique interplay between mitral valve disease and LA function; account for limitations of noninvasive assessment; and guide beneficial outcomes in each area of transcatheter mitral valve intervention. As a result, continuous transseptal LA pressure monitoring has developed into an indispensable instrument in successful percutaneous mitral valve intervention, complementing traditional noninvasive assessment.

Transcatheter management of valvular regurgitation beyond the aortic valve (mitral - tricuspid valve): Literature overview and future perspectives

The growth of the available transcatheter treatment approaches for the mitral and tricuspid position was accompanied by important clinical trials and studies through the last years. The selection of appropriate candidates for transcatheter techniques requires significant insight into anatomical limitations of each patient undergoing clinical evaluation. Furthermore, technological characteristics of the available devices, and risks and benefits of each potential therapy, play the most important role in a physician's decision. This knowledge should be valuable to both interventional cardiologists and researchers. This paper aims to offer a concise overview of the technological advances in this field of Interventional Cardiology. Trials and studies announced at the major interventional cardiology congresses during 2018 and 2019 were systematically reviewed. Moreover, a literature search in PubMed for the same period identified an amount of publications eligible for inclusion, based on their relevance to the subject, and their potential impact on current guidelines of good clinical practice.