Severe Atrial Functional Mitral Regurgitation: Clinical and Echocardiographic Characteristics, Management and Outcomes

Transcatheter edge-to-edge repair of atrial secondary mitral regurgitation positively influences atrial remodelling

BACKGROUND

Atrial secondary mitral valve regurgitation (ASMR) is a distinct anatomical subset of secondary mitral regurgitation (SMR). Evidence of the effect of transcatheter edge-to-edge repair (TEER) on left atrial (LA) anatomy and function, especially reverse remodelling (LARR), is still sparse.

METHODS AND RESULTS

We retrospectively evaluated all consecutive patients treated with TEER for mitral regurgitation (MR) in our centre between January 2013 and October 2023. Of the 597 patients with SMR, 103 patients (17.3%) met the inclusion criteria for ASMR. All patients in the ASMR group (mean age 79.4 ± 6.8 years, 71% female) were symptomatic (89% NYHA ≥ III) and had a mean logistic EuroScore of 22.5 ± 12.4%. TEER was successfully performed in all patients, and invasive LA mean pressures decreased intraprocedurally from 17.8 ± 5.7 to 13.1 ± 4.8 mmHg (P < 0.001). At hospital discharge, 94% of patients had mild residual or non/trace MR. At 1YFUP, the prevalence of residual moderate MR was 7% and 1% had severe MR. A significant reduction in LA volume compared with baseline, both at end-systole (151.4 ± 64 vs. 113 ± 64 mL, P < 0.001) and at end-diastole (119.8 ± 56 vs. 91.2 ± 56.9 mL, P < 0.001) could be observed. Seventy per cent of patients had a sustained decrease in NYHA class ≤ II. LARR, defined as LAESV decrease ≥15% at 1YFUP, was documented in 59% of patients. These patients were more likely to have lower post-interventional mitral valve mean pressure gradients (2.2 ± 0.8 mmHg vs. 2.8 ± 1.1 mmHg, P = 0.02) and lower BNP at discharge and at 1 month follow-up [319 (197.8 to 526) vs. 560 (279.3 to 929), P = 0.07, and 287.5 (191.3 to 386.3) vs. 506.5 (223.3 to 935.5), P = 0.06, respectively]. A multivariate logistic regression analysis identified pre-procedural MPG (P = 0.06, OR 0.92, CI 95% 0.85-1.00) and BNP at discharge (P = 0.11, OR 0.99, CI 95% 0.99-1.00) as independent predictors for the occurrence of LARR at 1 year.

CONCLUSIONS

Transcatheter mitral valve repair by edge-to-edge therapy represents a safe and effective therapeutic option in symptomatic patients with atrial secondary mitral regurgitation and might have the potential to induce left atrial reverse remodelling.

Impact of functional mitral regurgitation on outcomes of high-power short-duration pulmonary vein isolation in patients with atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is a common arrhythmia with significant health implications. Mitral regurgitation (MR) frequently coexists with AF and may affect treatment outcomes.

METHODS

This study aimed to analyze the impact of MR severity on the outcomes of high-power short-duration pulmonary vein isolation (PVI) in patients with AF. This observational cohort study involved 255 patients undergoing their first PVI. A total of 83 patients with moderate or severe MR were propensity score-matched with 83 controls based on age, sex, and body mass index (BMI). Procedural parameters, complication rates, AF recurrence within 1 year of PVI, and MR progression were analyzed.

RESULTS

Patients with moderate or severe MR demonstrated a higher percentage of atrial low-voltage areas (23.06% vs. 15.42%, p = 0.04) and more frequently required additional ablations (18.07% vs. 6.02%, p = 0.02). The 1‑year AF recurrence rates were identical between the groups (19.28% each, p = 1.00). The MR grade remained stable without significant differences between the groups after 1 year. However, among patients without AF recurrence, a statistically significant reduction in MR grade was observed after 1 year (1.54 ± 0.64 vs. 1.37 ± 0.53, p < 0.01). By contrast, patients with AF recurrence exhibited a trend toward worsening MR, although this change was not statistically significant (1.53 ± 0.57 vs. 1.75 ± 0.51, p = 0.09).

CONCLUSION

High-power short-duration PVI is safe and effective in AF patients, even among those with moderate or severe MR. Patients with moderate or severe functional MR exhibit more LA low-voltage areas and require more extensive ablations, especially cavotricuspid isthmus CTI ablation, reflecting a more complex disease profile. Maintaining a stable sinus rhythm can contribute to a reduction in MR grade.

Echocardiographic cardiac damage classification and clinical outcomes in atrial functional mitral regurgitation

BACKGROUND

Atrial functional mitral regurgitation (AFMR) arises from left atrial (LA) dilation, commonly associated with atrial fibrillation, and leads to progressive cardiac damage. This study evaluated the prognostic value of a novel echocardiographic cardiac damage classification system for patients with moderate or severe AFMR.

METHODS

In a retrospective multicentre study, 1007 patients with AFMR were stratified into four groups based on echocardiographic findings: group 1, LA damage (dilation); group 2, left ventricular damage (reduced ejection fraction and/or dilation); group 3, right heart damage (tricuspid regurgitation and/or pulmonary hypertension); and group 4, combined left and right heart damage. The primary outcome was a composite of all-cause death, heart failure hospitalisations and mitral valve (MV) interventions over a median follow-up of 3.0 years.

RESULTS

The cohort's mean age was 78±10 years, with 56% female. Event rates for the primary outcome were progressively higher across groups 1-4 (31.0%, 38.0%, 46.3% and 57.2%, respectively; p<0.001). After multivariable adjustment, group 4 was associated with a significantly higher risk of the primary outcome compared with group 1 (HR 1.65, 95% CI 1.29 to 2.11, p<0.001). This classification consistently stratified risks for individual components of the composite endpoint, particularly in patients without MV intervention.

CONCLUSIONS

A cardiac damage classification system based on echocardiographic parameters provides prognostic insights in patients with AFMR, identifying subgroups at higher risk of adverse outcomes. Future studies are needed to validate its use in guiding therapeutic decisions.

Machine-learning phenotyping of patients with functional mitral regurgitation undergoing transcatheter edge-to-edge repair: the MITRA-AI study

AIMS

Severe functional mitral regurgitation (FMR) may benefit from mitral transcatheter edge-to-edge repair (TEER), but selection of patients remains to be optimized.

OBJECTIVES

The aim of this study was to use machine-learning (ML) approaches to uncover concealed connections between clinical, echocardiographic, and haemodynamic data associated with patients' outcomes.

METHODS AND RESULTS

Consecutive patients undergoing TEER from 2009 to 2020 were included in the MITRA-AI registry. The primary endpoint was a composite of cardiovascular death or heart failure (HF) hospitalization at 1 year. External validation was performed on the Mitrascore cohort. 822 patients were included. The composite primary endpoint occurred in 250 (30%) patients. Four clusters with decreasing risk of the primary endpoint were identified (42, 37, 25, and 20% from Cluster 1 to Cluster 4, respectively). Clusters were combined into a high-risk (Clusters 1 and 2) and a low-risk phenotype (Clusters 3 and 4). High-risk phenotype patients had larger left ventriculars (LVs) (>107 mL/m2), lower left ventricular ejection fraction (<35%), and more prevalent ischaemic aetiology compared with low-risk phenotype patients. Within low-risk groups, permanent atrial fibrillation amplified that of HF hospitalizations. In the Mitrascore cohort, the incidence of the primary endpoint was 48, 52, 35, and 42% across clusters.

CONCLUSION

A ML analysis identified meaningful clinical phenotypic presentations in FMR undergoing TEER, with significant differences in terms of cardiovascular death and HF hospitalizations, confirmed in an external validation cohort.

Transcatheter Mitral Valve Replacement With Atrial Fixation for Treatment of Atrial Functional Mitral Regurgitation

BACKGROUND

Many patients with atrial functional mitral regurgitation are not suitable candidates for surgery or transcatheter repair. For transcatheter mitral valve replacement, a common contraindication is the risk of left ventricular outflow tract obstruction, particularly in patients with atrial functional mitral regurgitation, who have characteristically small left ventricles. Herein, we examine the outcomes of transcatheter mitral valve replacement using the AltaValve system, which employs atrial fixation thus minimizing left ventricular outflow tract obstruction risk.

METHODS

Patients with severe, symptomatic mitral regurgitation who were treated in the AltaValve early feasibility study or on the basis of a compassionate use exemption. The definition of atrial functional mitral regurgitation required the presence of: (1) severe mitral regurgitation; (2) atrial fibrillation; (3) normal left ventricular size; (4) left ventricular ejection fraction ≥50%; and (5) absence of organic mitral disease. Procedural outcomes, 30-day survival, and echo findings are reported.

RESULTS

Fourteen patients (71% women, mean age 77.9 years, Society of Thoracic Surgeons Predicted Risk of Mortality score 5.4%) were treated, including 11 via transseptal delivery and 3 via a transapical approach. Technical success and mitral regurgitation reduction from severe to none/trace were achieved in all cases. There were no cases of left ventricular outflow tract obstruction. All-cause mortality at 30 days was 14% (2/14). Class III/IV New York Heart Association status was reduced from 79% at baseline to 0% at 30 days. At 30 days, 11 of 12 surviving patients had an available echocardiogram; mitral regurgitation severity was trace/none in 90.9% (10/11) and mild in 9.1% (1/11).

CONCLUSIONS

The AltaValve system shows promising early procedural and clinical results for the unique anatomy of patients with atrial functional mitral regurgitation. Long-term clinical studies to demonstrate the benefit of this system are warranted.

Heart failure with preserved ejection fraction in atrial functional mitral regurgitation - Insight from the REVEAL-AFMR

BACKGROUND

Atrial functional mitral regurgitation (AFMR) and heart failure with a preserved ejection fraction (HFpEF) often coexist. However, the clinical impact of HFpEF in patients with AFMR has not been well characterized. This study aimed to determine clinical outcomes and response to mitral valve (MV) intervention or rhythm control therapy in patients with HFpEF and moderate AFMR (HFpEF-AFMR).

METHODS

This was a post-hoc analysis of the REVEAL-AFMR, a retrospective observational study involving patients with ≥ moderate AFMR. After excluding patients with severe MR, the presence of HFpEF was defined by the Universal definition.

RESULTS

Of 438 patients with moderate AFMR, 352 met the criteria of HFpEF (prevalence: 80 %). Compared to non-HFpEF-AFMR (n = 86), patients with HFpEF-AFMR were older and had greater symptom burden and a higher prevalence of severe tricuspid regurgitation (19 %). During a median follow-up of 33.2 months, a composite outcome of all-cause mortality or HF hospitalization occurred in 130 patients. Patients with HFpEF-AFMR had a 3.6-fold increased risk of the composite outcome compared to non-HFpEF-AFMR. While MV intervention was not associated with outcomes in HFpEF-AFMR, concomitant tricuspid valve (TV) procedures were associated with a better outcome than isolated MV intervention (HR 0.15, 95 %CI 0.04-0.54, p = 0.009). Catheter or surgical rhythm control showed a favorable outcome in HFpEF-AFMR and atrial fibrillation (HR 0.38, 95 %CI 0.17-0.87, p = 0.008).

CONCLUSION

HFpEF was substantially common in moderate AFMR and was associated with worse clinical outcomes. Simultaneous MV and TV intervention procedures or rhythm control therapy were associated with better clinical outcomes in HFpEF-AFMR.

Diagnosis of atrial cardiomyopathy: from the electrocardiogram to the new opportunities with multimodality imaging

Atrial cardiomyopathy (AC) has been defined by the European Heart Rhythm Association as "Any complex of structural, architectural, contractile, or electrophysiologic changes in the atria with the potential to produce clinically relevant manifestations".1 The left atrium (LA) plays a key role in maintaining normal cardiac function; in fact atrial dysfunction has emerged as an essential determinant of outcomes in different clinical scenarios, such as valvular diseases, heart failure (HF), coronary artery disease (CAD) and atrial fibrillation (AF). A comprehensive evaluation, both anatomical and functional, is routinely performed in cardiac imaging laboratories. Recent advances in imaging techniques offer opportunities for evaluation of LA function, fundamental in clinical practice for early cardiovascular (CV) risk estimation, choice of therapeutic intervention and follow up. In this review we explore the concept of AC, its diagnosis through a multimodal approach, ranging from the historical electrocardiogram to the latest CV imaging techniques and its clinical implications.

Atrial Functional Mitral Regurgitation Subtypes Undergoing Transcatheter Edge-to-Edge Repair: Suboptimal Outcomes in Atriogenic Hamstringing

BACKGROUND

Two subtypes of atrial functional mitral regurgitation (AFMR) have been described, one is characterized by Carpentier type I and the other by Carpentier type IIIb leaflet motion.

OBJECTIVES

The authors sought to analyze echocardiographic characteristics and outcomes of AFMR subtypes undergoing mitral valve transcatheter edge-to-edge repair (M-TEER).

METHODS

Of 1,047 consecutive patients who underwent M-TEER, the authors identified those with isolated mitral annulus dilation (Carpentier I), termed AFMR-IAD, and those with atriogenic hamstringing characterized by restricted posterior mitral leaflet motion (Carpentier IIIb), termed AFMR-AH. Echocardiographic baseline characteristics and outcomes up to 1-year were analyzed.

RESULTS

A total of 128 patients (12.2%) met AFMR criteria; 75 (58.6%) were identified as AFMR-IAD and 53 (41.4%) as AFMR-AH. AFMR-AH displayed greater left atrial and left ventricular volumes, greater mitral annulus, shorter and steeper posterior mitral leaflet, and more pronounced MR (all P < 0.05). Technical success was achieved in 98.7% (AFMR-IAD) and 86.8% (AFMR-AH) of patients (P = 0.009). At discharge, device detachments were exclusively observed in AFMR-AH (10.0%). MR ≤II was achieved in 95.6% and 78.6% at 30 days (P = 0.009) and in 93.0% and 74.1% at 1 year (P = 0.038) in patients with AFMR-IAD and AFMR-AH, respectively. AFMR-AH was associated with procedural failure (OR: 1.17 [95% CI: 1.00-1.38]; P = 0.045) at 30 days (43.4% vs 24.0%; P = 0.023) and all-cause mortality (HR: 2.54 [95% CI: 1.09-5.91]; P = 0.031) at 1 year (77% vs 92%, Kaplan-Meier estimated 1-year survival; P = 0.017).

CONCLUSIONS

AFMR-AH shows worse procedural and clinical outcomes following M-TEER than AFMR-IAD. Thus, vigilance regarding this pathology is warranted and alternative mitral valve therapies might need to be considered.

Mitral Regurgitation Evaluation in Modern Echocardiography: Bridging Standard Techniques and Advanced Tools for Enhanced Assessment

Mitral regurgitation (MR) is one of the most common valvular heart diseases worldwide. Echocardiography remains the first line and most effective imaging modality for the diagnosis of mitral valve (MV) pathology and quantitative assessment of MR. The advent of three-dimensional echocardiography has significantly enhanced the evaluation of MV anatomy and function. Furthermore, recent advancements in cardiovascular imaging software have emerged as step-forward tools, providing a powerful support for acquisition, analysis, and interpretation of cardiac ultrasound images in the context of MR. This review aims to provide an overview of the contemporary workflow for echocardiographic assessment of MR, encompassing standard echocardiographic techniques and the integration of semiautomated and automated ultrasound solutions. These novel approaches include advancements in segmentation, phenotyping, morphological quantification, functional grading, and chamber quantification.

Transcatheter Approaches to Atrial Functional Mitral Regurgitation: How Far Have We Come?

Functional mitral regurgitation (MR) is associated with increased cardiovascular morbidity and mortality and over the past decade, the diagnosis of atrial functional mitral regurgitation (aFMR) has been increasingly observed in the elderly, especially in those with atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF). Annular enlargement, perturbations of annular contraction, and atriogenic leaflet tethering distinguish the pathophysiology of aFMR from the one of ventricular origin. However, no consensus provides recommendations regarding the differential diagnosis and the subsequent management of aFMR. The advent of transcatheter mitral valve repair has paved the way for various treatments including edge-to-edge repair (TEER), mitral annuloplasty, and replacement, with optimistic results on short-medium-term outcome provided by preliminary studies. In parallel, rhythm control of AF for paroxysmal and persistent types, should be pursued to induce reverse remodeling and restoring the normal leaflet coaptation. In this setting, catheter ablation aiming for electrical isolation of the pulmonary veins is the most widely recognized and effective strategy for maintaining sinus rhythm. Nevertheless, arrhythmia-free survival is lower in patients with persistent and long-term persistent AF, leading to the adoption of hybrid strategies combining transcatheter endocardial ablation and thoracoscopic epicardial surgical ablation. This review provides an update on the diagnosis and treatment of aFMR, focusing on available transcatheter approaches that can be performed in the catheterization lab and electrophysiology lab.

Secondary Mitral Regurgitation: Updated Review with Focus on Percutaneous Interventional Management

Secondary mitral regurgitation (SMR) is associated with increased mortality and heart failure hospitalizations. The management of heart failure patients with SMR is complex and requires a multidisciplinary Heart Team approach. Guideline-directed medical therapies remain fundamental, yet in a proportion of patients SMR persists. In the past decade, transcatheter edge-to-edge repair (TEER) has been shown to improve survival in patients with SMR who remain symptomatic despite medical therapy. Technical advancements across newer generations of devices, improved imaging, and greater operator expertise have collectively contributed to the increased safety and efficacy of this procedure over time. Various emerging transcatheter mitral valve repair and replacement devices are currently under investigation and may offer superior, complementary or synergistic treatment options in patients ineligible for TEER. This review provides a state-of-the-art overview regarding the diagnosis of SMR, and currently available transcatheter mitral valve interventions and describes a contemporary approach to the management of SMR.

Atrial Functional Mitral Regurgitation: From Diagnosis to Current Interventional Therapies

Mitral regurgitation (MR) is one of the most common valvular pathologies worldwide, contributing to the morbidity and mortality of several cardiovascular pathologies, including heart failure (HF). Novel transcatheter treatment for MR has given the opportunity for a safe and feasible alternative, to surgery, in order to repair the valve and improve patient outcomes. However, after the results of early transcatheter edge-to-edge repair (TEER) trials, it has become evident that subcategorizing the mitral regurgitation etiology and the left ventricular function, in patients due to undergo TEER, is of the essence, in order to predict responsiveness to treatment and select the most appropriate patient phenotype. Thus, a novel MR phenotype, atrial functional MR (AFMR), has been recently recognized as a distinct pathophysiological entity, where the etiology of the regurgitation is secondary to annular dilatation, in a diseased left atrium, with preserved left ventricular function. Recent studies have evaluated and compared the outcomes of TEER in AFMR with ventricular functional MR (VFMR), with the results favoring the AFMR. In specific, TEER in this patient substrate has better echocardiographic and long-term outcomes. Thus, our review will provide a comprehensive pathogenesis and mechanistic overview of AFMR, insights into the echocardiographic approach of such patients and pre-procedural planning, discuss the most recent clinical trials and their implications for future treatment directions, as well as highlight future frontiers of research in the setting of TEER and transcatheter mitral valve replacement (TMVR) in AFMR patients.

Unraveling the interplay: early-stage atrial functional mitral regurgitation and left atrial electrical substrate in atrial fibrillation patients

Background

Atrial fibrillation (AF) triggers atrial remodeling, impacting atrial function and ablation efficacy. This remodeling leads to atrial cardiomyopathy and dilatation, linked to mitral regurgitation, forming atrial functional mitral regurgitation (aFMR). Our study explores the relationship between early-stage-aFMR and the atrial electrical architecture, focusing on left atrial bipolar voltage and low-voltage areas (LVAs) in AF patients.

Methods

We enrolled 282 patients undergoing redo-PVI after AF recurrence post-PVI. Echocardiography was performed prior to ablation, and only patients with no, mild, or mild-to-moderate aFMR were included. Ablation used radiofrequency and a 3D mapping system, with atrial voltage documented on each atrial wall. LVAs were calculated using high-density maps, and patients were followed for 15 months.

Results

Significant differences in left atrial voltage and LVA extent were observed based on aFMR severity. Patients with aFMR 1 + had significantly lower atrial voltage compared to no-aFMR, but no significant increase in LVAs. Patients with aFMR 2 + showed lower voltage amplitudes in all atrial regions and larger LVAs compared to no-aFMR patients. AF recurrence was significantly higher in the aFMR group (62.9% vs. 48.3%, p = 0.027) within 1 year. aFMR was associated with AF recurrence after adjusting for sex, age, and AF types (HR: 1.517, 95% CI: 1.057-2.184, p = 0.025).

Conclusion

aFMR in AF patients may indicate progressive atrial remodeling and left atrial cardiomyopathy, characterized by reduced atrial voltage and increased LVAs. aFMR is linked to PVI outcomes, suggesting its consideration in AF therapy decision-making.

Clinical Outcomes of Mitral Valve Surgery in Atrial Functional Mitral Regurgitation in the REVEAL-AFMR Registry

Importance

The characteristics and treatment strategies of atrial functional mitral regurgitation (AFMR) are poorly understood.

Objective

To investigate the prevalence, clinical characteristics, and outcomes of mitral valve (MV) surgery in AFMR.

Design, Setting, and Participants

This retrospective cohort study, called the Real-World Observational Study for Investigating the Prevalence and Therapeutic Options for Atrial Functional Mitral Regurgitation (REVEAL-AFMR), was conducted across 26 Japanese centers (17 university hospitals, 1 national center, 3 public hospitals, and 5 private hospitals). All transthoracic echocardiography procedures performed from January 1 to December 31, 2019, were reviewed to enroll adult patients (aged ≥20 years) with moderate or severe AFMR, defined by preserved left ventricular function, a dilated left atrium, and an absence of degenerative valvular changes. Data were analyzed from May 8, 2023, to May 16, 2024.

Exposures

Mitral valve surgery, with or without tricuspid valve intervention.

Main Outcomes and Measures

The primary composite outcome included heart failure hospitalization and all-cause mortality.

Results

In 177 235 patients who underwent echocardiography, 8867 had moderate or severe MR. Within this group, 1007 (11.4%) were diagnosed with AFMR (mean [SD] age, 77.8 [9.5] years; 55.7% female), of whom 807 (80.1%) had atrial fibrillation. Of these patients, 113 underwent MV surgery, with 92 (81.4%) receiving concurrent tricuspid valve surgery. Patients who underwent surgery were younger but had more severe MR (57.5% [n = 65] vs 9.4% [n = 84]; P < .001), a larger mean (SD) left atrial volume index (152.5 [97.8] mL/m2 vs 87.7 [53.1] mL/m2; P < .001), and a higher prevalence of heart failure (according to the New York Heart Association class III [marked limitation of physical activity] or class IV [symptoms of heart failure at rest], 26.5% [n = 30] vs 9.3% [n = 83]; P < .001) than those who remained under medical therapy. During a median follow-up of 1050 days (IQR, 741-1188 days), 286 patients (28.4%) experienced the primary outcome. Despite a more severe disease status, only the surgical group showed a decrease in natriuretic peptide levels at follow-up and had a significantly lower rate of the primary outcome (3-year event rates were 18.3% vs 33.3%; log-rank, P = .03). Statistical adjustments did not alter these findings.

Conclusions and Relevance

The findings of this cohort study suggest that in patients with AFMR, who were typically older and predominantly had atrial fibrillation, MV surgery was associated with lower rates of adverse clinical outcomes. Future studies are warranted to investigate a possible causal relationship to better regulate cardiovascular medicine.

Functional Mitral Regurgitation and Heart Failure With Preserved Ejection Fraction: Clinical Implications and Management

Heart failure with preserved ejection fraction (HFpEF) is highly prevalent and associated with worse cardiovascular outcomes. The pathophysiology of HFpEF mostly relies on the development of elevated left ventricle filling pressure, diastolic dysfunction, and atrial dilatation and impairment. This dynamic process may eventually lead to the development of functional mitral regurgitation (MR), characterized by mitral annular dilatation and consequent leaflet remodeling, in the context of preserved left ventricular ejection fraction. These observations highlight the possible common pathophysiology of MR and HFpEF. However, less is known about the prevalence and the clinical value of MR in the context of HFpEF. This review aims to provide an overview of the association and interplay between functional MR and HFpEF, discuss the underlying mechanisms that are common to these diseases, and summarize potential targeted pharmacological treatments.

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.

Left Atrium: A New Prognostic Marker and Therapeutic Target in Secondary Mitral Regurgitation?

Mitral regurgitation (MR) is one of the most common valvular abnormalities worldwide and can be subdivided into primary and secondary causes. Atrial MR consists of a novel type of secondary MR (SMR), most often observed in patients with AF and heart failure with preserved ejection fraction. The main pathophysiological mechanism of atrial MR is mitral valve annular dilatation. Recently published studies have highlighted the clinical significance of left atrium (LA) evaluation in the early diagnosis and prognosis of patients with primary MR. However, there are little data regarding the role of the LA in SMR. The present literature review aims to elucidate the use of the echocardiographic parameters regarding LA evaluation in the prognosis prediction and therapeutic strategy of patients with SMR.

Prevalence and prognostic impact of dynamic atrial functional mitral regurgitation assessed by isometric handgrip exercise

AIMS

In atrial functional mitral regurgitation (aFMR), a considerable proportion of patients displays a discrepancy between symptoms and echocardiographic findings at rest. Exercise testing plays a substantial role in assessing the haemodynamic relevance of mitral regurgitation (MR) and is recommended by current guidelines. Here, we aimed to assess the prevalence, extent, and prognostic impact of exercise-induced changes in patients with aFMR.

METHODS AND RESULTS

Patients with at least mild MR who underwent handgrip exercise echocardiography at the University Hospital Duesseldorf between January 2019 and September 2021 were enrolled. Patients were followed up for 1 year to assess clinical outcomes. Eighty patients with aFMR were included [median age: 80 (77-83) years; 53.8% female]. The median N-terminal pro-brain natriuretic peptide level was 1756 (1034-3340) ng/L. At rest, half of the patients (53.8%) had mild MR, 20 patients (25.0%) had moderate MR, and 17 patients (21.2%) had severe MR. In approximately every fifth patient (17.5%) with non-severe MR at rest, the MR became severe during exercise. Handgrip exercise led to a reclassification of MR severity in 28 patients (35.0%). At 1-year follow-up, adverse events occurred more often in patients with severe MR at rest (76.5%) and exercise-induced dynamic severe MR (66.7%) than in those with non-severe MR (28.6%; P < 0.001).

CONCLUSION

Handgrip exercise during echocardiography revealed exercise-induced changes in aFMR in every third patient. These data may have implications for therapeutic decision-making in symptomatic patients with non-severe aFMR at rest.

[Atrial functional mitral regurgitation: was this new entity needed?]

Atrial functional mitral regurgitation (AFMR) has recently been the focus of numerous original articles and reviews. This entity has been highlighted by population aging, the increasing prevalence of heart failure with preserved ejection fraction and atrial fibrillation, and the advent of the transcatheter techniques for mitral valve repair. AFMR is phenotype of mitral regurgitation that presents specific diagnostic challenges and current guidelines do not provide strong recommendations for its management. Cumulative data show that the outcomes of patients with severe AFMR are poor if left untreated. However, new heart failure therapies and minimally invasive techniques may have a positive impact on the outcomes of these patients.

The CINCH-FMR postmarket registry: Real-world long-term outcomes with percutaneous mitral valve repair with the Carillon Mitral Contour System®

BACKGROUND

The Carillon® Mitral Contour System® has been studied in 4 prospective controlled studies in the treatment of functional mitral regurgitation (FMR) where it has been found to reduce mitral regurgitation, reduce left ventricular and atrial volumes, and be associated with improvements in clinical parameters.

AIMS

The CINCH post-market registry is designed to evaluate immediate, mid-term and long-term outcomes from a post-approval study of the Carillon® device evaluated in real-world practice.

METHODS

The CINCH post-market registry is a single-arm study of percutaneous mitral annuloplasty with the Carillon device in patients with functional (secondary) mitral regurgitation and symptomatic congestive heart failure when utilized in real-world conditions. Patient selection, echocardiographic hemodynamic measurements, and patient follow-up requirements were performed per standard of care at each institution.

RESULTS

A total of 101 patients treated with the Carillon device at 13 sites in Germany were enrolled in the CINCH registry. The mean age was 75 ± 9 years, 57 % were male, and patient presentation included primarily NYHA class III (69 %) with MR grade 3 (68 %). Over 5 years of follow-up, all-cause mortality was 40.1 %, the incidence of HFH was 53.9 %, and the composite outcome of HFH or death was 66.4 %. At each follow-up interval through 5 years, statistically significant reductions in NYHA class (p < 0.05) and MR grade (p < 0.01) were reported.

CONCLUSIONS

In this "real world" registry of the Carillon Mitral Contour System, procedural safety and medium-term follow-up outcomes is similar to the outcomes seen in the prospective, controlled clinical trials, despite being used in populations of patients that extend outside of those studied in the trials. The use of this therapy in patients with atrial functional mitral regurgitation, and heart failure with preserved ejection fraction, was notable, since these types of patients were excluded from the prospective, controlled trials. This supports possible additional patient populations who might benefit from this type of mechanical therapy. The safety profile of this therapy in this registry and in the earlier trials may support a potential role in earlier forms of secondary mitral regurgitation.

Outcomes of COMBO therapy for severe mitral regurgitation compared with transcatheter edge-to-edge repair

Background

There are different types of transcatheter mitral valve repair (TMVr) currently in clinical use, including leaflet approximation, annular cinching, and restoration of the chordal apparatus of the mitral valve (MV). While the concomitant combination (COMBO) therapy of mitral transcatheter edge-to-edge repair (M-TEER) with another TMVr concept has been proven feasible, potentially offering patient-tailored treatment for severe mitral regurgitation (MR), a comparison with M-TEER alone has not been made.

Aims

To evaluate the procedural and clinical outcome of COMBO therapies compared with M-TEER alone.

Methods

We included consecutive patients undergoing COMBO and M-TEER between March 2015 and April 2018 at our Heart Valve Center, while excluding patients presenting a case of redo or with previous MV surgery. Procedural outcomes and all-cause mortality were compared between COMBO therapy vs. M-TEER alone.

Results

A total of 357 patients (mean age 78.9 ± 7.0 years, 53.2% male, M-TEER n = 322, COMBO n = 35; COMBO: MitraClip and the Carillon mitral contour system n = 26, MitraClip and Cardioband n = 5, and MitraClip and NeoChord n = 4) were analyzed. Patients with COMBO therapy had larger left chamber sizes, a lower left ventricular systolic ejection fraction (LVEF; COMBO: 37.4 ± 13.8%, M-TEER: 47.9 ± 14.3%, p < 0.001), and a more severe MR grade (p < 0.001). There were no significant differences in the prevalence of residual MR ≧2+. However, the need for re-intervention, always employing M-TEER, was more common in the COMBO group. During a mean 3.6-year long-term follow-up, there was no significant difference of all-cause mortality between both groups (Log rank p = 0.921).

Conclusions

COMBO therapy may still be a beneficial therapy option for patients with severe MR who already have a more dilated left ventricle (LV), a more severe MR, and a more pronounced LV systolic dysfunction. The higher need for re-intervention in the COMBO group may signal more complex anatomies and possibly underlines the necessity of treating significant MR earlier. Future research is required to establish the COMBO approach as a toolbox-like treatment option, thus offering a patient-tailored approach depending on the individual anatomy and pathology.

Outcomes of transcatheter edge-to-edge repair for atrial functional mitral regurgitation

BACKGROUND

The prognostic benefits of transcatheter edge-to-edge repair (TEER) remain unclear in patients with atrial functional mitral regurgitation (AFMR).

AIMS

We aimed to investigate the clinical outcomes of TEER for patients with AFMR.

METHODS

We retrospectively classified functional mitral regurgitation (FMR) patients undergoing TEER into those with AFMR or ventricular FMR (VFMR). A residual MR ≤1+ at discharge was considered optimal mitral regurgitation (MR) reduction, and an elevated mean mitral valve pressure gradient (MPG) was defined as an MPG ≥5 mmHg at discharge. The primary outcome was a composite of all-cause mortality and hospitalisation due to heart failure within one year.

RESULTS

Of 441 FMR patients, 125 patients were considered as having AFMR. Residual MR ≤1+ was associated with a lower risk of the composite outcome in both AFMR and VFMR patients, while an MPG ≥5 mmHg was associated with a higher risk of the composite outcome in patients with AFMR but not with VFMR. AFMR patients with residual MR ≤1+ and an MPG ≥5 mmHg, as well as those with residual MR >1+, had a higher incidence of the composite outcome than those with residual MR ≤1+ and an MPG <5 mmHg (50.7%, 41.8%, and 14.3%, respectively; p<0.001). This association was consistent after adjustment for clinical and echocardiographic characteristics.

CONCLUSIONS

An MR reduction to ≤1+ following TEER was associated with a lower risk of clinical outcomes in patients with AFMR, while an MPG ≥5 mmHg was related to a higher risk of clinical outcomes. Optimal MR reduction by TEER may have potential benefits on the prognosis of patients with AFMR, although the prognostic benefit may be attenuated by an elevated MPG.

Surgical strategy and outcomes for atrial functional mitral regurgitation: All functional mitral regurgitation is not the same!

OBJECTIVE

Functional mitral regurgitation (FMR) is a cardiac pathology that causes the mitral valve to malfunction, leading to mitral regurgitation (MR). The optimal strategy for FMR remains unclear, and FMR outcomes are poor. All etiologies of FMR might not be the same, and subdividing patients with FMR caused by atrial (AFMR) versus ventricular FMR pathology might be important. Herein, we present outcomes of patients with AFMR to define this "new" population.

METHODS

Data of patients who underwent mitral valve repair for MR from 2000 to 2020 were reviewed. Patients with degenerative/myxomatous disease, ejection fraction <50% (ventricular FMR), and miscellaneous etiologies including endocarditis and rheumatic disease were excluded to isolate a population of "pure" AFMR patients. Descriptive characteristics and outcomes data were analyzed.

RESULTS

Among 123 total AFMR patients, mean preoperative left atrial dimensions were enlarged to 4.9 (95% CI, 4.7-5.0) cm, whereas mean preoperative left ventricular diastolic dimensions remained near normal at 5.0 (95% CI, 4.9-5.2) cm. Preoperative atrial fibrillation was noted in 61% (74/123). Echocardiogram was performed in 58% (71/123) of patients at a median of 569 (interquartile range, 75-1782) days after surgery. Of those, 72% (51/71) had trivial or no MR, 22% (16/71) mild, and only 6% (4/71) moderate or greater MR. Only 1.6% (2/123) required redo mitral valve reoperation. Estimated 5-year survival was 74%.

CONCLUSIONS

Patients with AFMR do well after mitral valve repair using an annuloplasty ring, with low rates of reoperation, mortality, and recurrence of MR. Mitral annuloplasty should be considered the surgical therapy of choice for AFMR.

Impact of Transcatheter Edge-to-Edge Mitral Valve Repair on Atrial Functional Mitral Regurgitation from the GIOTTO Registry

Atrial functional mitral regurgitation (aFMR) has a peculiar pathophysiology that may have distinctive outcomes. We investigated the impact of transcatheter edge-to-edge repair in aFMR compared with other FMR etiologies. The GIOTTO (GIse registry Of Transcatheter treatment of MR) is a multicenter, prospective study enrolling patients with symptomatic MR treated with MitraClip up to 2020. We categorized patients with FMR as aFMR, ischemic FMR (iFMR), and nonischemic ventricular FMR (niFMR). The clinical end points were defined according to the Mitral Valve Academic Research Consortium. Of 1,153 patients, 6% had aFMR, 47% iFMR, and 47% niFMR. Patients with aFMR were older, mostly women, and had a higher atrial fibrillation rate. They had better left ventricular ejection fraction and smaller left ventricular volumes, with no difference in mitral effective regurgitant orifice area. The acute device and procedural success rates were similar among the groups. At the longest available follow-up (median 478 days, interquartile range 91 to 741 days), the rate of MR ≥2+ was similar among the groups. Patients with aFMR had a lower rate of cardiovascular death and heart failure than patients with iFMR (hazard ratio [HR] 0.43, p = 0.02) and niFMR (HR 0.45, p = 0.03). The aFMR etiology remained independently associated with the composite outcome, together with postprocedural MR ≤1+ (HR 0.63, p <0.01) and peripheral arteriopathy (HR 1.82, p = 0.003). The results of this GIOTTO subanalysis suggested that aFMR is less prevalent and associated with better outcomes compared with other causes of FMR treated by transcatheter edge-to-edge repair. Postprocedural MR >1+, peripheral vasculopathy, non-aFMR were independent predictors of worse outcomes.

Assessment of mitral valve geometry in nonvalvular atrial fibrillation patients with or without ventricular dysfunction: insights from high volume rate three-dimensional transesophageal echocardiography

Meticulous understanding of the mechanisms underpinning mitral regurgitation in atrial fibrillation (AF) patients is crucial to optimize therapeutic strategies. The morphologic characteristics of mitral valves in atrial functional mitral regurgitation (FMR) patients with and without left ventricular (LV) dysfunction were evaluated by high volume rate (HVR) three-dimensional transesophageal echocardiography (3D-TEE). In our study, 68 of 265 AF patients who underwent 3D-TEE were selected, including 36 patients with AF, FMR, and preserved LV function (AFMR group) and 32 patients with AF, FMR, and LV dysfunction (VFMR group). In addition, 36 fever patients without heart disease were included in the control group. Group comparisons were performed by one-way analysis of variance for continuous variables. The left atrium (LA) was enlarged in the AFMR and VFMR groups compared with the control group. The mitral annulus (MA) in the AFMR group was enlarged and flattened compared with the control group and was smaller than in the VFMR group. The annulus area fraction was significantly diminished in the AFMR and VFMR groups, indicative of reduced MA contractility. The posterior mitral leaflet (PML) angle was smallest in the AFMR group and largest in the control group, whereas the distal anterior mitral leaflet angle did not significantly differ among the three groups. LA remodeling causes expansion of the MA and reduced MA contractility, disruption of the annular saddle shape, and atriogenic PML tethering. Comparison of atrial FMR patients with and without LV dysfunction indicates that atriogenic PML tethering is an important factor that aggravates FMR. HVR 3D-TEE improves the 3D temporal resolution greatly.

Impact of eccentric jet on outcomes in patients with atrial functional mitral regurgitation: An echocardiographic study

BACKGROUND

Previous studies have reported the mechanisms underlying atrial functional mitral regurgitation (A-FMR). Recently, A-FMR subtypes based on mitral regurgitation (MR) mechanisms were proposed: "central jet" due to insufficient leaflet remodeling and "eccentric jet" due to atriogenic tethering. However, their prognostic value remains unclear. Therefore, this study investigated the impact of A-FMR subtypes on clinical outcomes.

METHODS

Outpatients with significant A-FMR between January 2013 and December 2016 were retrospectively reviewed. They were classified into two subtypes according to the MR jet's direction. All-cause mortality, heart failure hospitalization, and any mitral valve interventions were the primary composite endpoint.

RESULTS

Among 101 patients with significant A-FMR, 32% had eccentric jet. The primary endpoint was observed in 56 patients during the follow-up period (median 0.7 years, range 0.1-4.2 years). Kaplan-Meier curves demonstrated that the composite endpoint was higher among patients with eccentric jet than those with central jet (log-rank p < 0.001). Eccentric jet (hazard ratio [HR] 2.46, 95% confidence interval [CI] 1.28-4.73; p = 0.007), age (HR 1.06, 95% CI 1.02-1.11; p = 0.002), symptoms (HR 6.22, 95% CI 2.18-17.8; p < 0.001), severe MR (HR 3.97, 95% CI 1.92-8.18; p < 0.001), and significant tricuspid regurgitation (TR; HR 2.00, 95% CI 1.01-3.97; p = 0.047) were independent predictors of the composite endpoint.

CONCLUSIONS

Patients with eccentric jet had poorer outcomes than those with central jet. Eccentric jet, age, symptoms, severe MR, and significant TR were independently associated with poor outcomes.

Incidence, risk factors, and outcomes of atrial functional mitral regurgitation in patients with atrial fibrillation or sinus rhythm

AIMS

Atrial functional mitral regurgitation (AFMR) has been associated with atrial fibrillation (AF) and heart failure with preserved ejection fraction. However, data on incident AFMR are scarce. We aimed to study the incidence, risk factors, and clinical significance of AFMR in AF or sinus rhythm (SR).

METHODS AND RESULTS

Adults with new diagnosis of AF and adults in SR were identified. Patients with >mild MR at baseline, primary mitral disease, cardiomyopathy, left-sided valve disease, previous cardiac surgery, or with no follow-up echocardiogram were excluded. Diastolic dysfunction (DD) was indicated by ≥2/4 abnormal diastolic function parameters [mitral medial e', mitral medial E/e', tricuspid regurgitation velocity, left atrial volume index (LAVI)]. Overall, 1747 patients with AF and 29 623 in SR were included. Incidence rate of >mild AFMR was 2.6 per 100 person-year in new-onset AF and 0.7 per 100 person-year in SR, P < 0.001. AF remained associated with AFMR in a propensity score-matched analysis based on age, sex, and comorbidities between AF and SR [hazard ratio: 3.80 (95% confidence interval 3.04-4.76)]. Independent risk factors associated with incident AFMR were age ≥65 years, female sex, LAVI, and DD in both AF and SR, in addition to rate (vs. rhythm) control in AF. Incident AFMR was independently associated with all-cause death in both groups (both P < 0.001).

CONCLUSIONS

AF conferred a three-fold increase in the risk of incident AFMR. DD, older age, left atrial size, and female sex were independent risk factors in both SR and AF, while rhythm control was protective. AFMR was universally associated with worse mortality.

Clinical significance of substrate characteristics and ablation outcomes in patients with atrial fibrillation and significant functional mitral regurgitation

Background

Atrial fibrillation (AF) and mitral regurgitation (MR) have a complex interplay. Catheter ablation (CA) of AF may be a potential method to improve the severity of MR in AF patients.

Methods

Patients with symptomatic AF and moderate to severe MR who underwent catheter ablation from 2011 to 2021 were retrospectively included in the study. Patients' baseline characteristics and electrophysiological features were examined. These patients were classified as group 1 with improved MR and group 2 with refractory MR after CA.

Results

Fifty patients (age 60.2 ± 11.6 years, 29 males) were included in the study (32 in group 1 and 18 in group 2). Group 1 patients had a lower CHA2DS2-VASc score (1.7 ± 1.5 vs. 2.7 ± 1.5, P = 0.005) and had a lower incidence of hypertension (28.1% vs. 66.7%, P = 0.007) and diabetes mellitus (3.1% vs. 22.2%, P = 0.031) as compared to group 2 patients. Electroanatomic three-dimensional (3D) mapping showed that group 1 patients demonstrated less scars on the posterior bottom of the left atrium compared to group 2 patients (12.5% vs. 66.7%, P < 0.001). AF recurrence was not different between the two groups. After multivariate logistic regression analysis, a posterior bottom scar in the left atrium independently predicted refractory MR despite successful AF ablation.

Conclusion

Most patients with AF and MR showed improvement of MR after AF ablation. A scar involving the posterior bottom of the left atrium is associated with poor recovery of MR.

Outcomes of transcatheter edge-to-edge repair for atrial functional mitral regurgitation: A meta-analysis of observational studies

BACKGROUND

Transcatheter edge-to-edge repair (TEER) may have potential benefits in the treatment of atrial functional mitral regurgitation (AFMR), but robust evidence is currently lacking. We conducted a systematic review and meta-analysis to investigate the clinical outcomes of TEER for AFMR, including comparisons to ventricular functional MR (VFMR).

METHODS

MEDLINE and EMBASE were searched through January 2023 to identify studies eligible for analysis. The primary outcome was postprocedural MR severity. Postprocedural New York Heart Association (NYHA) functional class classification and all-cause mortality were also evaluated. Outcomes were stratified into short term (postprocedure to 6 months) and long term (6 months to 2 years).

RESULTS

A total of eight observational studies met the inclusion criteria, enrolling 539 AFMR and 3486 VFMR patients. Postprocedural MR grade ≤2 in the AFMR group was observed in 93.7% (454/491 patients; 95% confidence interval (CI), 91.1%-96.2%, I2  = 24.3%) and 97.1% (89/93 patients; 95% CI, 92.9%-100%, I2  = 26.4%) in short- and long-term follow-up, respectively. There was no difference in the rates of postprocedural MR grade ≤2 between AFMR and VFMR either in short-term (risk ratio [RR], 1.00 [95% CI, 0.95-1.06]; p = 0.90; I2  = 53%) or long-term follow-up (RR, 1.08 [95% CI, 0.89-1.32]; p = 0.44; I2  = 22%). Similarly, no difference was observed between AFMR and VFMR in the rates of postprocedural NYHA class ≤2 or all-cause mortality.

CONCLUSION

TEER provides similar clinical outcomes for AFMR and VFMR. A high rate of MR grade ≤2 was observed in patients at both short- and long-term follow-ups. Further prospective studies with TEER versus medical therapy and/or rhythm control for AFMR are warranted.

Progression of Non-Significant Mitral and Tricuspid Regurgitation after Surgical Aortic Valve Replacement for Aortic Regurgitation

Little is known about the natural history of non-significant mitral and tricuspid regurgitation (MR and TR) following surgical aortic valve replacement (SAVR) for aortic regurgitation (AR). We retrospectively analyzed 184 patients (median age 64 (IQR, 55-74) years, 76.6% males) who underwent SAVR for AR. Subjects with significant non-aortic valvulopathies, prior/concomitant valvular interventions, or congenital heart disease were excluded. The cohort was evaluated for MR/TR progression and, based on the latter's occurrence, for echocardiographic and clinical indices of heart failure and mortality. By 5.8 (IQR, 2.8-11.0) years post-intervention, moderate or severe MR occurred in 20 (10.9%) patients, moderate or severe TR in 25 (13.5%), and either of the two in 36 (19.6%). Patients who developed moderate or severe MR/TR displayed greater biventricular disfunction and functional limitation and were less likely to be alive at 7.0 (IQR, 3.4-12.1) years compared to those who did not (47.2 vs. 79.7%, p < 0.001). The emergence of significant MR/TR was associated with preoperative atrial fibrillation/flutter, symptomatic heart failure, and above-mild MR/TR as well as concomitant composite graft use, but not with baseline echocardiographic measures of biventricular function and dimensions, aortic valve morphology, or procedural aspects. In conclusion, among patients undergoing SAVR for AR, significant MR/TR developed in one fifth by six years, correlated with more adverse course, and was anticipated by baseline clinical and echocardiographic variables.

Arrythmia-Mediated Valvular Heart Disease

The aging population is rising at record pace worldwide. Along with it, a steep increase in the prevalence of atrial fibrillation and heart failure with preserved ejection fraction is to be expected. Similarly, both atrial functional mitral and tricuspid regurgitation (AFMR and AFTR) are increasingly observed in daily clinical practice. This article summarizes all current evidence regarding the epidemiology, prognosis, pathophysiology, and therapeutic options. Specific attention is addressed to discern AFMR and AFTR from their ventricular counterparts, given their different pathophysiology and therapeutic needs.

Functional Mitral and Tricuspid Regurgitation across the Whole Spectrum of Left Ventricular Ejection Fraction: Recognizing the Elephant in the Room of Heart Failure

Functional mitral regurgitation (FMR) and tricuspid regurgitation (FTR) occur due to cardiac remodeling in the presence of structurally normal valve apparatus. Two main mechanisms are involved, distinguishing an atrial functional form (when annulus dilatation is predominant) and a ventricular form (when ventricular remodeling and dysfunction predominate). Both affect the prognosis of patients with heart failure (HF) across the entire spectrum of left ventricle ejection fraction (LVEF), including preserved (HFpEF), mildly reduced (HFmrEF), or reduced (HFrEF). Currently, data on the management of functional valve regurgitation in the various HF phenotypes are limited. This review summarizes the epidemiology, pathophysiology, and treatment of FMR and FTR within the different patterns of HF, as defined by LVEF.

Atrial Dysfunction in Significant Atrial Functional Mitral Regurgitation: Phenotypes and Prognostic Implications

BACKGROUND

Atrial functional mitral regurgitation (AFMR) is associated with increased morbidity and mortality. Left atrial (LA) size and function in AFMR are poorly characterized. We aimed to assess LA function by reservoir strain (LASr) and estimated reservoir work (LAWr) and their impact on outcome in AFMR.

METHODS

Consecutive patients at our institution between 2001 and 2019 and with significant (moderate or greater) AFMR were examined. LAWr was estimated as LASr×LA reservoir volume, and patients were grouped by median LASr and LAWr. Outcomes were all-cause death or heart failure hospitalizations.

RESULTS

Five hundred fifteen AFMR patients were followed up for 5 (1-17) years. Patients had previously documented atrial fibrillation (AF; 37%), heart failure with preserved ejection fraction (HFpEF) without AF (24%), or both (HFpEF+AF, 39%). LA volume was largest in AF, while LA function parameters were most impaired in the combined HFpEF+AF group. During follow-up, patients with low LASr or LAWr had higher risk of death (P<0.001) and heart failure hospitalization (P<0.05). In Cox regression analyses, low LASr and LAWr, but not LA volume or left ventricular function, were associated with a higher risk of death (LASr: hazard ratio, 2.3 [95% CI, 1.6-3.5]; LAWr: hazard ratio, 3.4 [95% CI, 2.4-4.9]; both P<0.001) after adjustment for clinical and echocardiographic confounders. Low LASr and LAWr were strongest associated with death in HFpEF and HFpEF+AF.

CONCLUSIONS

LA reservoir function but not LA size is a robust predictor of outcome in significant AFMR. This provides mechanistic insights into the interplay of functional versus geometric LA changes in AFMR.

Severe mitral regurgitation in nonagenarians: Impact of symptomatic status, frailty and etiology on management and outcomes

BACKGROUND

Data regarding mitral regurgitation (MR) in extremely elderly patients are limited. The aim of the present study was to assess symptomatic status, frailty, etiology and outcomes for nonagenarians with severe MR.

METHODS

Single-center cohort study of patients ≥90 years of age with at least 3+ MR on echocardiography between September 2010 and August 2018. Out of a total of 11,998 patients with at least 3+ MR, 267 patients were included in the present study.

RESULTS

The average age was 93.5 ± 2.6 years, and 57% were female. At baseline, 88% were symptomatic, with mean Charlson co-morbidity index of 6 ± 2 points, and mean frailty score of 2.9 ± 1.4 points. Primary MR was present in 50%, secondary in 47%, and prosthetic valve dysfunction in 3%. Among patients with primary MR, the most common etiology was mitral annular calcification (58%). In comparison, the most common etiology of secondary MR was atrial functional MR (52%). Of all, 95% were treated conservatively, and 5% underwent interventional management. Among 253 patients who had follow-up data with a median follow-up of 14 months (25th-75th interquartile range: 3-31 months), 191 patients (75%) died. Mortality trended higher in the conservative group versus the interventional group (60% vs. 22%, log-rank P = 0.063).

CONCLUSIONS

Most nonagenarians with significant MR were symptomatic at presentation, had elevated Charlson co-morbidity index and frailty scores. Etiologies of MR were almost equally distributed between primary and secondary causes. The vast majority of nonagenarians with significant MR were conservatively managed.

Atrial secondary mitral regurgitation: prevalence, characteristics, management, and long-term outcomes

BACKGROUND

The prevalence, clinical characteristics, management and long-term outcomes of patients with atrial secondary mitral regurgitation (ASMR) are not well described.

METHODS

We performed a retrospective, observational study of consecutive patients with grade III/IV MR determined by transthoracic echocardiography. The aetiology of MR was grouped as being either primary (due to degenerative mitral valve disease), ventricular SMR (VSMR: due to left ventricular dilatation/dysfunction), ASMR (due to LA dilatation), or other.

RESULTS

A total of 388 individuals were identified who had grade III/IV MR; of whom 37 (9.5%) had ASMR, 113 (29.1%) had VSMR, 193 had primary MR (49.7%), and 45 (11.6%) were classified as having other causes. Compared to MR of other subtypes, patients with ASMR were on average older (median age 82 [74-87] years, p < 0.001), were more likely to be female (67.6%, p = 0.004) and usually had atrial fibrillation (83.8%, p = 0.001). All-cause mortality was highest in patients with ASMR (p < 0.001), but similar to that in patients with VSMR once adjusted for age and sex (hazard ratio [HR] 0.81, 95% confidence interval [CI] 0.52-1.25). Hospitalisation for worsening heart failure was more commonly observed in those with ASMR or VSMR (p < 0.001) although was similar between these groups when age and sex were accounted for (HR 0.74, 95% CI 0.34-1.58). For patients with ASMR, the only variables associated with outcomes were age and co-morbidities.

CONCLUSIONS

ASMR is a prevalent and distinct disease process associated with a poor prognosis, with much of this related to older age and co-morbidities.

Atrial functional mitral regurgitation: prevalence, characteristics and outcomes from the National Echo Database of Australia

AIMS

Atrial functional mitral regurgitation (AFMR) is characterised by left atrial and consequent mitral annular dilatation causing mitral regurgitation. AFMR is likely to become more common with population ageing, alongside increases in atrial fibrillation and heart failure with preserved ejection fraction; conditions causing atrial dilatation. Here, we aim to define the prevalence and characterise the patient and survival characteristics of AFMR in the National Echocardiographic Database of Australia (NEDA).

METHODS AND RESULTS

14 004 adults with moderate or severe FMR were identified from NEDA. AFMR or ventricular FMR (VFMR) was classified by LA size, LV size and LVEF. AFMR was found in 40% (n=5562) and VFMR in 60% (n=8442). Compared with VFMR, the AFMR subgroup were significantly older (mean age 78±11 years), with a higher proportion of females and of AF. Participants were followed up for a median of 65 months (IQR 36-116 months). After adjustment for age, sex, AF, and pulmonary hypertension, the prognosis for VFMR was significantly worse than for AFMR (HR 1.57, 95% CI 1.47 to 1.68 for all-cause and 1.73, 95% CI 1.60 to 1.88, p<0.001 for both). After further adjustment for LVEF, mortality rates were similar in VFMR and AFMR patients (HR 0.93, p=NS), though advancing age and pulmonary hypertension remained independently associated with prognosis.

CONCLUSIONS

AFMR is a common cause of significant functional MR that predominantly affects elderly female patients with AF. Advancing age and pulmonary hypertension independently associated with survival in FMR. Prognosis was better in AFMR compared with VFMR; however, this difference was accounted for by LV systolic impairment and not by MR severity.

Differences in clinical and echocardiographic features and outcomes between atrial functional mitral regurgitation patients with and without posterior mitral leaflet bending

BACKGROUND

Posterior mitral leaflet (PML) bending is a cause of atrial functional mitral regurgitation (AFMR). We aimed to investigate differences in clinical and echocardiographic features and outcomes between AFMR patients with and without PML bending.

METHODS

We retrospectively examined 118 AFMR patients with atrial fibrillation (AF), mild or greater MR without degenerative mitral valve changes, and left ventricular ejection fraction ≥50 %. Patients were classified by the presence of PML bending: PML bending (n=24) and no PML bending (n=94). PML bending was defined as PML-to-anterior mitral leaflet angle ratio ≥3.1 calculated using receiver operating characteristics analysis for eccentric MR jet toward left atrial posterior wall. The study endpoint was a composite of cardiac death, admission for heart failure, and mitral valve surgery.

RESULTS

Overall, a total of 88 patients (75 %) had mild MR. There were no between-group differences in clinical and echocardiographic characteristics including AF duration and cardiac cavities size except for the length of inward bending of the left ventricular posterobasal wall and the mitral annular area. The 36-month event-free survival for the composite endpoint was significantly lower in the PML bending group (63 % vs. 78 %; Log-rank p=0.047). In multivariate analysis, PML bending was also associated with the composite outcome.

CONCLUSIONS

AFMR patients with PML bending may have worse outcomes than those without PML bending despite similar clinical features.

The fate of concomitant mild mitral regurgitation in aortic insufficiency: A neglected subject

Objectives

Mitral regurgitation (MR) is commonly experienced by patients with aortic insufficiency (AI), and in its mild form, it is considered benign. However, the progression of concomitant mild regurgitation after the aortic valve surgery (AVS) for AI is poorly characterized. The current study aimed to define the long-term outcomes of MR after surgery and identify the risk factors involved in deterioration.

Methods

Patients presenting with moderate/severe AI and concomitant mild MR (n = 347) between January 2013 and December 2021 were enrolled. MR grade was assessed by transthoracic echocardiography during the follow-up, and deterioration is defined as an increase in grade to moderate or severe MR from the previous follow-up echocardiography. Analysis of risk factors for early mortality, MR deterioration, and long-term mortality was performed.

Results

A total of 278 patients (84.8%) among 328 survivors had at least one follow-up echocardiography, and complete follow-up occurred for 316 patients (96.3%). Mild MR improved to trivial or none in 194 patients (69.8%), progressed to persistent mild MR for 74 patients (26.6%), and deteriorated for 10 patients (3.6%). Preoperative atrial fibrillation [odds ratio (OR), 23.09; 95% confidence interval (CI), 4.35-122.54] and rheumatic AI (OR, 11.61; 95% CI, 1.26-106.85) were shown to be independent risk factors for MR deterioration by generalized linear mixed analysis.

Conclusion

Progression of concomitant mild MR is rare in patients with AI after AVS. However, rheumatic AI and preoperative atrial fibrillation increase the probability of MR deterioration. Careful follow-up for this cohort of patients is recommended.

Machine learning identifies pathophysiologically and prognostically informative phenotypes among patients with mitral regurgitation undergoing transcatheter edge-to-edge repair

AIMS

Patients with mitral regurgitation (MR) present with considerable heterogeneity in cardiac damage depending on underlying aetiology, disease progression, and comorbidities. This study aims to capture their cardiopulmonary complexity by employing a machine-learning (ML)-based phenotyping approach.

METHODS AND RESULTS

Data were obtained from 1426 patients undergoing mitral valve transcatheter edge-to-edge repair (MV TEER) for MR. The ML model was developed using 609 patients (derivation cohort) and validated on 817 patients from two external institutions. Phenotyping was based on echocardiographic data, and ML-derived phenotypes were correlated with 5-year outcomes. Unsupervised agglomerative clustering revealed four phenotypes among the derivation cohort: Cluster 1 showed preserved left ventricular ejection fraction (LVEF; 56.5 ± 7.79%) and regular left ventricular end-systolic diameter (LVESD; 35.2 ± 7.52 mm); 5-year survival in Cluster 1, hereinafter serving as a reference, was 60.9%. Cluster 2 presented with preserved LVEF (55.7 ± 7.82%) but showed the largest mitral valve effective regurgitant orifice area (0.623 ± 0.360 cm2) and highest systolic pulmonary artery pressures (68.4 ± 16.2 mmHg); 5-year survival ranged at 43.7% (P-value: 0.032). Cluster 3 was characterized by impaired LVEF (31.0 ± 10.4%) and enlarged LVESD (53.2 ± 10.9 mm); 5-year survival was reduced to 38.3% (P-value: <0.001). The poorest 5-year survival (23.8%; P-value: <0.001) was observed in Cluster 4 with biatrial dilatation (left atrial volume: 312 ± 113 mL; right atrial area: 46.0 ± 8.83 cm2) although LVEF was only slightly reduced (51.5 ± 11.0%). Importantly, the prognostic significance of ML-derived phenotypes was externally confirmed.

CONCLUSION

ML-enabled phenotyping captures the complexity of extra-mitral valve cardiac damage, which does not necessarily occur in a sequential fashion. This novel phenotyping approach can refine risk stratification in patients undergoing MV TEER in the future.

Differences in patterns of progression of secondary mitral regurgitation

AIMS

Little data exist about the natural history and disease progression of secondary mitral regurgitation (SMR). We sought to study the temporal progression of left-sided volumes and functions in patients who progress to develop severe SMR.

METHODS AND RESULTS

We screened patients with chronic severe SMR who had at least one previous transthoracic echocardiography showing non-severe MR. Unsupervised phenotypic clustering based on baseline and rate of change in left ventricular (LV) and left atrial (LA) volumes, ejection fraction (EF), and MR severity progression identified two different phenotypes. We then compared them in terms of clinical characteristics, mechanistic and anatomical features, management, and outcomes. A total of 257 patients were included. Cluster 1 started with lower EF and LA strain and higher LV and LA volumes compared with Cluster 2, with a slower progression into severe SMR. At the onset of severe MR, Cluster 2 still had higher EF, lower LV volumes, but similar LA volumes and strain, and less proportionate SMR, compared with Cluster 1. They also had higher tenting height and more compensatory leaflet growth. On follow-up, Cluster 1 had more ventricular-directed therapies, whereas Cluster 2 received more mitral valve interventions. While the heart failure burden was higher in Cluster 1, there was no difference in mortality rates.

CONCLUSION

Based on disease progression, two distinct progression patterns of SMR exist, having different anatomical and mechanistic features with variation in management and outcomes.

Incidence and causal association of functional atrial mitral regurgitation in HFpEF

Heart failure with preserved ejection fraction (HFpEF) is as common as heart failure with reduced ejection fraction. Atrial fibrillation (AF), as well as the presence of mitral regurgitation (MR), is highly prevalent in these patients. Atrial functional MR (AFMR) is a type of functional MR characterized by severe left atrial dilatation and remodeling with normal left ventricular (LV) dimensions and function. Dilatation of the mitral annulus is considered to be the main underlying mechanism, though the leaflets and the rest of the mitral apparatus play significant role in the development of MR, mainly in patients with long standing AF. There are several echocardiographic differences between atrial and ventricular functional MR, better identified with 3D echocardiography. Significant AFMR impairs prognosis, especially of patients with HFpEF, and this is important while they represent a group of under-diagnosed and under-treated patients. Finally, because focused medical evidence-based approach is not available yet, it seems that the prevention of left atrial dilatation and early restoration of sinus rhythm (SR) is the best therapeutic option.

Patient Selection for Mitral Transcatheter Edge-to-Edge Repair

Mitral regurgitation (MR) is one of the most common valvular heart diseases, with many patients remaining non-suitable for surgical interventions. Transcatheter edge-to-edge repair (TEER) is a rapidly evolving procedure that allows safe and effective reduction of MR in high-risk patients. However, adequate patient selection through clinical assessment and imaging modalities remains a key factor for procedural success. In the following review, we highlight recent developments in TEER technologies that are expanding the target population and currently available imaging modalities that allow detailed evaluation of the mitral valve and surrounding structures for optimal patient selection.

Pathophysiology, Echocardiographic Diagnosis, and Treatment of Atrial Functional Mitral Regurgitation: JACC State-of-the-Art Review

The conventional view holds that functional mitral regurgitation (MR) is caused by restriction of leaflet motion resulting from displacement of the papillary muscle-bearing segments of the left ventricle. In the past decade, evidence has accrued suggesting functional MR can also be caused by left atrial enlargement. This underrecognized cause of secondary MR-atrial functional MR (AF-MR)-is mechanistically linked to annular enlargement, perturbations of annular contraction, and atriogenic leaflet tethering. AF-MR has been described in patients with atrial fibrillation and heart failure with preserved ejection fraction. Preliminary data suggest rhythm control may decrease MR severity in patients with atrial fibrillation. Additionally, several studies have reported reductions in MR and symptomatic improvement with restrictive annuloplasty and transcatheter edge-to-edge repair. This review discusses the pathophysiology, echocardiographic diagnosis, and treatment of AF-MR. AF-tricuspid regurgitation is also discussed.

Atrial Functional Mitral Regurgitation: A JACC: Cardiovascular Imaging Expert Panel Viewpoint

Functional or secondary mitral regurgitation (MR) is associated with increased cardiovascular morbidity and mortality. Mechanistically, secondary MR is attributable to an imbalance between mitral leaflet tethering and closure forces, leading to poor coaptation. The pathophysiology of functional MR is most often the result of abnormalities in left ventricular function and remodeling, seen in ischemic or nonischemic conditions. Less commonly and more recently recognized is the scenario in which left ventricular geometry and function are preserved, the culprit being mitral annular enlargement associated with left atrial dilatation, termed atrial functional mitral regurgitation (AFMR). This most commonly occurs in the setting of chronic atrial fibrillation or heart failure with preserved ejection fraction. There is variability in the published reports and in current investigations as to the definition of AFMR. This paper reviews the pathophysiology of AFMR and focus on the need for a collective definition of AFMR to facilitate consistency in reported data and enhance much-needed research into outcomes and treatment strategies in AFMR.

Outcomes After Transcatheter Edge-to-Edge Mitral Valve Repair According to Mitral Regurgitation Etiology and Cardiac Remodeling

BACKGROUND

Transcatheter edge-to-edge repair (TEER) has been increasingly used for selected patients with mitral regurgitation (MR), but limited data are available regarding clinical outcomes in patients with varied etiology and mechanism of MR.

OBJECTIVES

The aim of this study was to evaluate the outcomes of TEER according to etiology and left ventricular (LV) and left atrial remodeling.

METHODS

Consecutive patients who underwent TEER between 2007 and 2020 were included in the analysis. Among patients with functional MR (FMR), those with predominant LV remodeling were classified as having ventricular FMR (v-FMR), whereas those without LV remodeling but predominant left atrial remodeling were classified as having atrial FMR (a-FMR). The primary outcome was a composite of all-cause mortality and heart failure hospitalization at 2 years and was compared among patients with degenerative MR (DMR), a-FMR, and v-FMR.

RESULTS

A total of 1,044 patients (11% with a-FMR, 48% with v-FMR, and 41% with DMR) with a mean Society of Thoracic Surgeons score of 8.6 ± 7.8 underwent TEER. Patients with a-FMR had higher rates of atrial fibrillation and severe tricuspid regurgitation with larger left and right atria, whereas patients with v-FMR had lower LV ejection fractions with larger LV dimensions. Residual MR more than moderate at discharge was not significantly different among the 3 groups (5.2% vs 3.2% vs 2.6%; P = 0.37). Compared with patients with DMR, 2-year event rates of the primary outcome were significantly higher in patients with a-FMR and v-FMR (21.6% vs 31.5% vs 42.3%; log-rank P < 0.001).

CONCLUSIONS

Despite excellent procedural outcomes, patients with a-FMR and v-FMR had worse clinical outcomes compared with those with DMR.

Clinical Outcomes With Transcatheter Edge-to-Edge Repair in Atrial Functional MR From the EXPAND Study

BACKGROUND

Although transcatheter edge-to-edge repair (TEER) has been shown to improve clinical outcomes and improve quality of life in patients with symptomatic secondary mitral regurgitation (SMR) and left ventricular dysfunction, its effect in patients with atrial SMR (aSMR) has not been well described.

OBJECTIVES

The aim of this study was to assess the safety, echocardiographic outcomes, and clinical effectiveness of TEER for aSMR.

METHODS

Patients with aSMR in the prospective, observational, multicenter EXPAND (A Contemporary, Prospective, Multi-Center Study Evaluating Real-World Experience of Performance and Safety for the Next Generation of MitraClip Devices) study were identified by an echocardiography core laboratory. Follow-up occurred at discharge, 30 days, and 1 year. Key endpoints included mitral regurgitation (MR) severity, functional class, heart failure hospitalizations, mortality, and 30-day major adverse events.

RESULTS

Among 1,041 patients enrolled in EXPAND, 835 patients had evaluable echocardiograms at baseline. Of these, 53 patients had aSMR and 360 had ventricular SMR (vSMR). In the aSMR cohort, TEER resulted in a significant reduction in MR through 1 year (MR grade ≤2 in 100.0%), significantly increased 1-year Kansas City Cardiomyopathy Questionnaire score (+26.6 ± 30.5 points; P < 0.0001), and improved functional class from baseline, similar to the effects among patients with vSMR (MR grade ≤2 in 99.5% at 1 year, 1-year increase in Kansas City Cardiomyopathy Questionnaire score 21.23 ± 24.92 points). Major adverse events at 30 days and leaflet adverse events at 1 year were infrequent in both groups.

CONCLUSIONS

In a prospective, real-world, global registry, TEER for aSMR was associated with significant MR reduction and improvement in quality of life and functional class, similar to patients with vSMR. This suggests that TEER may provide clinical benefit in patients with atrial fibrillation with SMR in the setting of heart failure with preserved ejection fraction. (The MitraClip® EXPAND Study of the Next Generation of MitraClip® Devices; NCT03502811).