Transcatheter Edge-to-Edge Repair of Mitral Valve Regurgitation: Closing the Gap to Broaden the Coverage.

Background: Transcatheter edge-to-edge repair of mitral valve (M-TEER) is reasonable consideration in symptomatic patients with severe degenerative mitral regurgitation (MR) who are at high or prohibitive risk of surgical repair or replacement. In symptomatic patients on maximally tolerated medical therapy with severe secondary MR from left ventricular systolic dysfunction, M-TEER is reasonable therapeutic option. Methods: In this review, we present a comprehensive overview of the most recent literature and considerations for M-TEER in patients excluded from key trials. These include patients with cardiogenic shock, acute ischemic MR, atrial functional MR, failed surgical mitral valve prosthesis and pulmonary hypertension. Conclusions: M-TEER is feasible and a reasonable alternative option for these patient populations with a significant clinical benefit. However, randomized clinical trials are needed to ascertain findings from these observational studies.

Prevalence and factors associated with atrial mitral and tricuspid regurgitation in patients with atrial fibrillation.

BACKGROUND: This study aimed to examine the prevalence of atrial tricuspid regurgitation (ATR) and atrial mitral regurgitation (AMR) in the setting of atrial fibrillation (AFib) and identify variables related to the severity of both types of regurgitation. METHODS: Cross-sectional study evaluating data from transthoracic echocardiograms performed during 2019. We included patients with AFib during the examination, and without primary valve disease or other significant heart disease. RESULTS: Four-hundred and thirty-two patients fulfilled the inclusion criteria (mean age 77.5±9.2 years, 49.1% women). We observed significant ATR in 14.8%, and significant AMR in 1.4% of patients. ATR and AMR severities were equal in 49.3% of patients, and 41% displayed greater ATR severity. ATR prevalence was significantly greater among women (23.1% vs 6.8%, p < 0.001), but AMR prevalence was similar between genders (1.9% vs .9%, p = 0.443). Variables related to greater ATR severity were: female sex (OR: 2.61, 95%CI: 1.60-4.24), left atrial (LA) volume (OR: 3.58, 95%CI: 1.50-8.55), systolic pulmonary artery pressure (OR: 1.10, 95%CI: 1.07-1.13), and moderate AMR (OR: 2.21, 95%CI: 1.22-4.00). Variables related to greater AMR severity were female sex (OR: 1.96, 95%CI: 1.24-3.09), LA volume (OR: 11.68, 95%CI: 5.29-25.80), and body mass index (OR: .94, 95%CI: .90-.98). CONCLUSIONS: In the context of AFib, ATR was more prevalent than AMR and prevailed in women. LA enlargement was associated with higher degrees of both AMR and ATR. Pulmonary hypertension was also independently associated with ATR, as well as greater AMR severity, suggesting possible adaptive changes in leaflets that might modify the atrial regurgitation incidence.

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.

Atrial Mitral and Tricuspid Regurgitation: Sex Matters. A Call for Action to Unravel the Differences Between Women and Men.

Atrial functional regurgitation is caused by atrioventricular annulus dilation, with normal leaflets and ventricular dimensions and function within the normal range. Its occurrence, in both mitral and tricuspid valves, implies a worse prognosis due to the hemodynamic derangement they produce, but also constitutes a marker of greater comorbidity and more advanced disease. Predisposing conditions for these heart valve dysfunctions are mainly atrial fibrillation and heart failure with preserved ejection fraction. However, other factors like female sex also may be involved and influence their incidence, especially for atrial tricuspid regurgitation. In the present review, we analyze sex differences in the reported prevalence of atrial mitral and tricuspid regurgitation, and suggest possible mechanisms involved. Finally, we underline potential therapeutic and preventive strategies to reduce the burden of these heart valve disorders and discuss research gaps.

Geometric differences of the mitral valve apparatus in atrial and ventricular functional mitral regurgitation.

BACKGROUND: Functional mitral regurgitation (FMR) occurs in patients with annular dilation (atrial, aFMR) or patients with left ventricular (LV) disease (ventricular, vFMR). Meticulous understanding of the mechanisms underpinning regurgitation is crucial to optimize therapeutic strategies. METHODS: Patients with moderate-severe FMR were identified from a registry of patients referred for transcatheter mitral valve intervention. In addition, controls without cardiovascular disease were identified. Differences in the geometry of the LV and mitral valve apparatus (including leaflet and tenting geometry, papillary muscle displacement and movement, annular dimensions, and dynamism) between atrial and ventricular FMR, and control subjects, were assessed using multiphasic cardiac CT. RESULTS: Of 183 FMR patients, 18 patients (10%) were found to have aFMR. The remaining patients had either ischemic or non-ischemic ventricular FMR. In aFMR, both increasing LV end-systolic volume (rho 0.701, p â€‹< â€‹0.01) and left atrial volume (rho 0.909, p â€‹< â€‹0.01) were associated with larger annular area. By contrast, in vFMR larger annular area was most strongly associated with larger left atrial volume (rho 0.63, p â€‹< â€‹0.01). In controls, increased annular area was associated with larger LVEDV (rho 0.78, p â€‹< â€‹0.01) and LVESV (rho 0.824, p â€‹< â€‹0.01), but not left atrial size (rho 0.16, p â€‹= â€‹0.45). Ventricular FMR comprised apicolaterally displaced, akinetic posteromedial papillary muscles, resulting in pronounced leaflet tethering, leaflet elongation compared to controls, and only modest relative LA dilatation. Compared to vFMR, aFMR was characterised by marked relative annular dilation, smaller but discernible mitral valve tenting, shorter leaflet lengths when related to annular size, but normal papillary geometry. CONCLUSION: FMR is characterised by multiple changes within the mitral valve complex. Atrial and ventricular FMR differ significantly in terms of the drivers of annular size, and geometry and function of the subvalvular apparatus. This highlights the need to consider these as separate disease entities.

Clinical and echocardiographic outcomes of transcatheter mitral valve repair in atrial functional mitral regurgitation.

BACKGROUND: Isolated atrial fibrillation can cause mitral regurgitation (MR) in patients with normal left ventricular systolic function and no organic disease of the mitral valve. Little information is available regarding outcomes of Mitraclip in patients with atrial functional mitral regurgitation (AFMR). We aimed to evaluate 12-month clinical and echocardiographic outcomes of transcatheter mitral valve repair (TMVR) with MitraClip in patients with AFMR compared to those with ventricular functional or degenerative/mixed MR. METHODS: Registry-based analysis of all consecutive patients who underwent TMVR and were included in the Spanish Registry of Mitraclip. Changes in MR and NYHA functional class, and a combined endpoint including all-cause mortality and hospitalizations due to heart failure were the main outcomes. RESULTS: Overall, 1074 (69.1% male, 73.3 ± 10.2 years-old) patients were analyzed in this report. 48 patients (4.5%) presented AFMR. AFMR was significantly reduced after TMVR, with a procedural success rate of 91.7%, and this reduction persisted at 12-month (p < 0.001). Patients with AFMR showed a significant functional improvement at 6- and 12-month follow-up in our series (baseline: NYHA III 70.8% IV 18.8% vs. 1-year: NYHA III 21.7% IV 0%; p < 0.001). The probability of survival free of readmission for heart failure and all-cause mortality within the first year after TMVR was 74.9%. Procedural and clinical outcomes, as well as recurrent rates of MR were similar acutely and at 1-year compared to other etiologies. CONCLUSION: TMVR in patients with AFMR showed no significant differences compared to ventricular functional or degenerative/mixed MR regarding MR reduction or clinical outcomes.

Ex Vivo Model of Functional Mitral Regurgitation Using Deer Hearts.

Transcatheter therapies are emerging for functional mitral regurgitation (FMR) treatment, however there is lack of pathological models for their preclinical assessment. We investigated the applicability of deer hearts for this purpose.8 whole deer hearts were housed in a pulsatile flow bench. At baseline, all mitral valves featured normal coaptation. The pathological state was induced by 60-minutes intraventricular constant pressurization. It caused mitral annulus dilation (antero-posterior diameter increase from 31.8 ± 5.6 mm to 39.5 ± 4.9 mm, p = 0.001), leaflets tethering (maximal tenting height increase from 7.3 ± 2.5 mm to 12.7 ± 3.4 mm, p < 0.001) and left ventricular diameter increase (from 67.8 ± 7.5 mm to 79.4 ± 6.5 mm, p = 0.004). These geometrical reconfigurations led to restricted mitral valve leaflets motion and leaflet coaptation loss. Preliminary feasibility assessment of two FMR treatments was performed in the developed model.Deer hearts showed ability to dilate under constant pressurization and have potential to be used for realistic preclinical research of novel FMR therapies. Graphical abstract figure legend: Deer heart mitral valve fiberscopic and echocardiographic images in peak systole at baseline and after inducing the pathological conditions representing functional mitral regurgitation. In the pathological conditions lack of coaptation between the leaflets, enlargement of the antero-posterior distance (red dashed line) and the left ventricular diameter (orange dashed line) were observed.

Imaging of the left atrium: pathophysiology insights and clinical utility.

Left atrial imaging and detailed knowledge of its pathophysiology, especially in the context of heart failure, have become an increasingly important clinical and research focus. This development has been accelerated by the growth of non-invasive imaging modalities, advanced image processing techniques, such as strain imaging, and the parallel emergence of catheter-based left atrial interventions like pulmonary vein ablation, left atrial appendage occlusion, and others. In this review, we focus on novel imaging methods for the left atrium, their pathophysiological background, and their clinical relevance for various cardiac conditions and diseases.