Extramitral Valvular Cardiac Involvement in Patients With Significant Secondary Mitral Regurgitation

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.

Cardiac Damage Staging Predicts Outcomes in Aortic Valve Stenosis After Aortic Valve Replacement: Meta-Analysis

Background

The prognostic value of cardiac damage staging classification based on the extent of extravalvular damage has been proposed in moderate/severe aortic stenosis (AS).

Objectives

The purpose of this study was to assess the association of cardiac damage staging with mortality across the spectrum of patients with AS following aortic surgical or transcatheter aortic valve replacement (AVR).

Methods

We conducted a pooled meta-analysis of Kaplan-Meier-derived reconstructed time-to-event data from studies published through February 2023.

Results

In total, 16 studies (n = 14,499) met our eligibility criteria and included 12,282 patients with symptomatic severe AS and 2,217 patients with asymptomatic severe/moderate AS. For patients with symptomatic severe AS, all-cause mortality was 24.0%, 27.7%, 38.0%, 56.3%, and 57.3% at 5 years in patients with cardiac damage stage 0, 1, 2, 3, and 4, respectively (stage 0 as reference; HR in stage 1: 1.30 [95% CI: 1.03-1.64]; P = 0.029; stage 2: 1.74 [95% CI: 1.41-2.16]; P < 0.001; stage 3: 2.92 [95% CI: 2.35-3.64]; P < 0.001, and stage 4: 3.51 [95% CI: 2.79-4.41]; P < 0.001). For patients with asymptomatic moderate/severe AS, all-cause mortality was 19.3%, 36.9%, 51.7%, and 67.8% at 8 years in patients with cardiac damage stage 0, 1, 2, and 3 to 4, respectively (HR in stage 1: 1.70 [95% CI: 1.21-2.38]; P = 0.002; stage 2: 2.20 [95% CI: 1.60-3.02]; P < 0.001; and stage 3 to 4: 3.90 [95% CI: 2.79-5.47]; P < 0.001).

Conclusions

In patients undergoing AVR across the symptomatic and severity spectrum of AS, cardiac damage staging at baseline has important prognostic implications. This pooled meta-analysis in patients undergoing AVR suggests that staging of baseline cardiac damage could be considered for timing and selection of therapy in patients with moderate or severe AS to determine the need for earlier AVR or adjunctive pharmacotherapy to prevent irreversible cardiac damage and improve the long-term prognosis.

Impact of extra-mitral valve cardiac involvement in patients with primary mitral regurgitation undergoing transcatheter edge-to-edge repair

BACKGROUND

In the context of primary mitral regurgitation (PMR), the selection of patients for transcatheter edge-to-edge repair (TEER) does not include a systematic assessment of PMR-associated cardiac remodelling.

AIMS

We aimed to investigate the epidemiology and prognostic significance of different phenotypes of extra-mitral valve (MV) cardiac involvement in a large series of patients with PMR referred for TEER.

METHODS

The study included 654 patients from the multicentre Italian GIOTTO registry, stratified into groups according to extra-mitral valve (MV) cardiac involvement. The primary endpoint was all-cause death at 2-year follow-up.

RESULTS

Patients with no cardiac involvement (NI; n=58), left heart involvement (LHI; n=343) and right heart involvement (RHI; n=253) were analysed. Acute technical success was achieved in 98% of patients. Kaplan-Meier curve analysis revealed significantly worse survival in patients with LHI and RHI (p=0.041). On multivariate Cox regression analysis, extra-MV cardiac involvement, haemoglobin level and technical success were independent predictors of the primary endpoint occurrence.

CONCLUSIONS

Grading cardiac involvement may help refine risk stratification, since at least 1 group of extra-MV cardiac involvement represents in itself a negative predictor of midterm outcome.

Heart Failure and Secondary Mitral Regurgitation: A Contemporary Review

Secondary mitral regurgitation (SMR) in patients with heart failure (HF) is associated with significant morbidity and mortality. In recent decades, SMR has received increasing scientific attention. Advances in echocardiography, computed tomography and cardiac magnetic resonance imaging have refined our ability to diagnose, quantify and characterize SMR. Concurrently, the treatment options for this high-risk patient population have continued to evolve. Guideline-directed medical therapies including beta-blockers, angiotensin receptor-neprilysin inhibitors, mineralocorticoid receptor antagonists and sodium-glucose cotransporter-2 inhibitors target the underlying cardiomyopathy, and along with diuretics to treat pulmonary congestion, remain the cornerstone of therapy. Cardiac resynchronization therapy also reduces MR, alleviates symptoms and prolongs life in selected HF patients with SMR. While data supporting surgical mitral valve repair or replacement for SMR are limited, transcatheter edge-to-edge repair (TEER) has been demonstrated to improve survival, reduce the rate of hospitalization for heart failure, and improve functional capacity and quality-of-life in select patients with SMR who remain symptomatic despite medical therapy. Emerging transcatheter mitral valve repair and replacement technologies are undergoing investigation in TEER-eligible and TEER-ineligible patients. The optimal management of HF patients with SMR requires a multidisciplinary team of cardiologists, cardiac surgeons, imaging experts, and other organ specialists to select the best treatment approaches to improve the prognosis of these high-risk patients.

Staging Heart Failure Patients With Secondary Mitral Regurgitation Undergoing Transcatheter Edge-to-Edge Repair

BACKGROUND

Secondary mitral regurgitation (SMR) is a progressive disease with characteristic pathophysiological changes that may influence prognosis. Although the staging of SMR patients suffering from heart failure with reduced ejection fraction (HFrEF) according to extramitral cardiac involvement has prognostic value in medically treated patients, such data are so far lacking for edge-to-edge mitral valve repair (M-TEER).

OBJECTIVES

This study sought to classify M-TEER patients into disease stages based on the phenotype of extramitral cardiac involvement and to assess its impact on symptomatic and survival outcomes.

METHODS

Based on echocardiographic and clinical assessment, patients were assigned to 1 of the following HFrEF-SMR groups: left ventricular involvement (Stage 1), left atrial involvement (Stage 2), right ventricular volume/pressure overload (Stage 3), or biventricular failure (Stage 4). A Cox regression model was implemented to investigate the impact of HFrEF-SMR stages on 2-year all-cause mortality. The symptomatic outcome was assessed with New York Heart Association functional class at follow-up.

RESULTS

Among a total of 849 eligible patients who underwent M-TEER for relevant SMR from 2008 until 2019, 9.5% (n = 81) presented with left ventricular involvement, 46% (n = 393) with left atrial involvement, 15% (n = 129) with right ventricular pressure/volume overload, and 29% (n = 246) with biventricular failure. An increase in HFrEF-SMR stage was associated with increased 2-year all-cause mortality after M-TEER (HR: 1.39; CI: 1.23-1.58; P < 0.01). Furthermore, higher HFrEF-SMR stages were associated with significantly less symptomatic improvement at follow-up.

CONCLUSIONS

The classification of M-TEER patients into HFrEF-SMR stages according to extramitral cardiac involvement provides prognostic value in terms of postinterventional survival and symptomatic improvement.