Impact of asymmetric tethering on outcomes after edge-to-edge mitral valve repair for secondary mitral regurgitation

Echocardiographic Screening for Transcatheter Edge-to-Edge Mitral Valve Repair: Correlation Between Transthoracic and Transesophageal Assessment

BACKGROUND

In patients with significant mitral regurgitation (MR) undergoing transcatheter edge-to-edge repair (M-TEER), assessment of mitral valve (MV) anatomy is essential. While transthoracic echocardiography (TTE) is the initial diagnostic tool, transesophageal echocardiography (TOE) provides better anatomical details. The study aims to assess whether TTE is as effective as TOE in selecting patients with severe MR who are eligible for M-TEER.

METHODS

From January to December 2024, patients with severe MR eligible for TEER were enrolled at the Fondazione Monasterio Heart Hospital, Italy. They underwent a comprehensive TTE and TOE examination. Cardiologists assessed the severity of MR and valve anatomy using specific protocols. Measurements included MV area, MV gradient, posterior leaflet length, fossa ovalis high, presence of fails, clefts, and calcifications. Three levels of anatomic complexity were defined to determine eligibility for TEER.

RESULTS

The study includes 40 patients with severe MR. The correlation between TTE and TOE for key parameters was strong, with coefficients ranging from 0.734 to 0.901, indicating high agreement between the two methods. The comparison of categorical features showed high agreement between TTE and TOE in detecting critical MV conditions, with kappa values ranging from 0.717 to 0.930. The agreement for classifying patients as suitable for M-TEER was 87.5%, indicating moderate consistency between the two methods.

CONCLUSIONS

TTE may be a viable alternative to TOE for assessing MV anatomy and function before M-TEER in MR patients, especially in high-volume centers. While TTE strongly correlated with TOE for most parameters, TOE was superior for some features. Further research is needed to refine the clinical application of TTE and to define patient selection criteria for its use as the primary imaging modality for pre-procedural M-TEER screening.

Overall impact of tethering and of its symmetric and asymmetric subtypes on early and long-term outcome of transcatheter edge-to-edge repair of significant mitral valve regurgitation

BACKGROUND

Tethering is a common condition of the mitral valve apparatus in the presence of significant regurgitation. Its impact on outcomes of transcatheter edge-to-edge repair (TEER) remains poorly characterized.

METHODS

We appraised the prevalence, features, procedural details, and outcomes of patients with or without mitral valve tethering in a prospective multicenter observational study. The primary endpoint was the risk of cardiac death or rehospitalization for heart failure at mid-term follow-up.

RESULTS

We included 2238 patients, 1467 (65.5 %) without tethering and 771 (34.5 %) with tethering (487 [21.8 %] with symmetric and 284 [12.7 %] with asymmetric tethering). Several differences in baseline features were evident among groups, yet procedural results were similar. After a median of 14 months, rates of cardiac death or rehospitalization for heart failure was significantly higher at unadjusted analysis in patients with tethering (191 [24.8 %] vs. 272 [18.5 %] in those without tethering, p = 0.001), but weres similar between tethering subtypes (p = 0.666). At adjusted analysis, the presence of any tethering was no longer a significant predictor of cardiac death or rehospitalization for heart failure, and the same results were obtained focusing on tethering subtypes (all p > 0.05).

CONCLUSIONS

Tethering is common among patients with an indication to TEER, and is associated with adverse baseline and procedural features. In spite of this, device and procedural success rates are not significantly impacted by the presence of tethering that does not even have a negative prognostic effect at follow-up. Accordingly, tethering should not be considered a contraindication to TEER in suitable patients.

Relevance of mexiletine in the era of evolving antiarrhythmic therapy of ventricular arrhythmias

Despite impressive developments in the field of ventricular arrhythmias, there is still a relevant number of patients with ventricular arrhythmias who require antiarrhythmic drug therapy and may, e.g., in otherwise drug and/or ablation refractory situations, benefit from agents known for decades, such as mexiletine. Through its capability of blocking fast sodium channels in cardiomyocytes, it has played a minor to moderate antiarrhythmic role throughout the recent decades. Nevertheless, certain patients with structural heart disease suffering from drug-refractory, i.e., mainly amiodarone refractory ventricular arrhythmias, as well as those with selected forms of congenital long QT syndrome (LQTS) may nowadays still benefit from mexiletine. Here, we outline mexiletine's cellular and clinical electrophysiological properties. In addition, the application of mexiletine may be accompanied by various potential side effects, e.g., nausea and tremor, and is limited by several drug-drug interactions. Thus, we shed light on the current therapeutic role of mexiletine for therapy of ventricular arrhythmias and discuss clinically relevant aspects of its indications based on current evidence.

The Evolving Concept of Secondary Mitral Regurgitation Phenotypes: Lessons From the M-TEER Trials

Conflicting results from 2 randomized clinical trials of transcatheter mitral valve edge-to-edge repair in secondary mitral regurgitation (SMR) have led to the recognition that SMR is a heterogeneous disease entity presenting with different functional and morphological phenotypes. This review summarizes the current knowledge on SMR caused primarily by atrial secondary mitral regurgitation (aSMR) and ventricular SMR pathology. Although aSMR is generally characterized by severe left atrial enlargement in the setting of preserved left ventricular anatomy and function, different patterns of mitral annular distortion cause different phenotypes of aSMR. In ventricular SMR, the relation of SMR severity to left ventricular dilation as well as the degree of pulmonary hypertension and right ventricular dysfunction are important phenotypic characteristics, which are key for a better understanding of prognosis and treatment response.

Transcatheter edge-to-edge mitral valve repair in mitral regurgitation: current status and future prospects

INTRODUCTION

Mitral regurgitation (MR) is associated with substantial morbidity and mortality. Within the past 15 years, mitral valve edge-to-edge repair (M-TEER) has developed from an experimental approach to a guideline-recommended, safe, and effective treatment option for patients with severe primary or secondary mitral regurgitation.

AREAS COVERED

This review covered relevant publications of M-TEER and summarizes the development of M-TEER devices within the last 15 years. It outlines anatomical challenges which drove the evolution of M-TEER devices, provides an overview about the current state of clinical application and research, and offers an outlook into the future of transcatheter mitral valve treatment.

EXPERT OPINION

The development and refinement of new M-TEER device generations offer the possibility to treat a wide range of mitral valve anatomies. Choosing the best device for the individual anatomic properties of the patients and considering comorbidities is the key to maximized MR reduction, minimalized complication rates, and thus optimized postinterventional prognosis. Independent from prognostic implications, quality of life has become an important patient-centered outcome that can be improved by M-TEER in virtually all patients treated.

Mitral valve transcatheter edge-to-edge repair

Mitral regurgitation (MR) is the most prevalent valvular heart disease and, when left untreated, results in reduced quality of life, heart failure, and increased mortality. Mitral valve transcatheter edge-to-edge repair (M-TEER) has matured considerably as a non-surgical treatment option since its commercial introduction in Europe in 2008. As a result of major device and interventional improvements, as well as the accumulation of experience by the interventional cardiologists, M-TEER has emerged as an important therapeutic strategy for patients with severe and symptomatic MR in the current European and American guidelines. Herein, we provide a comprehensive up-do-date overview of M-TEER. We define preprocedural patient evaluation and highlight key aspects for decision-making. We describe the currently available M-TEER systems and summarise the evidence for M-TEER in both primary mitral regurgitation (PMR) and secondary mitral regurgitation (SMR). In addition, we provide recommendations for device selection, intraprocedural imaging and guiding, M-TEER optimisation and management of recurrent MR. Finally, we provide information on major unsolved questions and "grey areas" in M-TEER.