Determinants of the degree of functional mitral regurgitation in patients with systolic left ventricular dysfunction: A quantitative clinical study

Efficacy of mitral valve repair in combination with coronary revascularization for moderate ischaemic mitral regurgitation: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The efficacy of mitral valve repair (MVR) in combination with coronary artery bypass grafting (CABG) for moderate ischaemic mitral regurgitation (IMR) remains unclear. To evaluate whether MVR + CABG is superior to CABG alone, the authors conducted a systematic review and meta-analysis of existing randomized controlled trials (RCTs).

METHODS

The authors searched PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials for eligible RCTs from the date of their inception to October 2023. The primary outcomes were operative (in-hospital or within 30 days) and long-term (≥ 1 year) mortality. The secondary outcomes were postoperative stroke, worsening renal function (WRF), and reoperation for bleeding or tamponade. The authors performed random-effects meta-analyses and reported the results as risk ratios (RRs) with 95% CIs.

RESULTS

Six RCTs were eligible for inclusion. Compared with CABG alone, MVR + CABG did not increase the risk of operative mortality (RR, 1.244; 95% CI, 0.514-3.014); however, it was also not associated with a lower risk of long-term mortality (RR, 0.676; 95% CI, 0.417-1.097). Meanwhile, there was no difference between the two groups in terms of postoperative stroke (RR, 2.425; 95% CI, 0.743-7.915), WRF (RR, 1.257; 95% CI, 0.533-2.964), and reoperation for bleeding or tamponade (RR, 1.667; 95% CI, 0.527-5.270).

CONCLUSIONS

The findings of this meta-analysis suggest that MVR + CABG fails to improve the clinical outcomes of patients with moderate IMR compared to CABG alone.

Interpapillary muscle distance independently predicts recurrent mitral regurgitation

OBJECTIVE

Ischaemic secondary mitral regurgitation (ISMR) after surgery is due to the displacement of papillary muscles resulting from progressive enlargement of the left ventricle end-diastolic diameter (LVEDD). Our aim was to prove that if the interpapillary muscle distance (IPMD) is surgically stabilized, an increase in LVEDD will not lead to a recurrence of ischaemic mitral regurgitation (MR).

METHODS

Ninety-six patients with ISMR, who underwent surgical revascularisation and annuloplasty, were randomly assigned in a 1:1 ratio to undergo papillary muscle approximation (PMA). At the 5-year follow-up, we assessed the correlation between PMA and echocardiographic improvements, the effect size of PMA on echocardiographic improvements, and a prediction model for recurrent MR using inferential tree analysis.

RESULTS

There was a significant correlation between PMA and enhancements in both the α and β angles (Spearman's rho > 0.7, p < 0.01). The α angle represents the angle between the annular plane and either the A2 annular-coaptation line or the P2 annular-coaptation line. The β angle indicates the angle between the annular plane and either the A2 annular-leaflet tip line or the P2 annular-leaflet tip line. PMA led to substantial improvements in LVEDD, tenting area, α and β angles, with a large effect size (Hedge's g ≥ 8, 95% CI ORs ≠ 1). The most reliable predictor of recurrent MR grade was the interpapillary distance, as only patients with an interpapillary distance greater than 40 mm developed ≥ 3 + grade MR. For patients with an IPMD of 40 mm or less, the best predictor of recurrent MR grade was LVEDD. Among the patients, only those with LVEDD greater than 62 mm showed moderate (2+) MR, while only those with LVEDD less than or equal to 62 mm had absent to mild (1+) MR.

CONCLUSION

Prediction of recurrent ischaemic MR is not independent of progressive LVEDD increase. PMA-based surgical procedure stabilises IPMD.

Potential Effects of Mild Atrial Secondary Mitral Regurgitation in Patients With Isolated Atrial Fibrillation

BACKGROUND

Patients with only moderate atrial secondary mitral regurgitation (asMR) frequently develop heart failure (HF). Mechanisms of HF with moderate asMR and the impact of mild asMR remain unclarified. Although mild/moderate primary mitral regurgitation is compensated by left ventricular (LV) dilatation, the LV is not dilated in asMR. We hypothesized that patients with mild asMR without LV dilatation may have impaired hemodynamics and higher risks of subsequent symptomatic HF deterioration.

METHODS

Stroke volume, cardiac output, and systolic pulmonary artery pressure were measured by echocardiography in 142 patients with isolated atrial fibrillation and 30 healthy controls. The prognosis of patients with isolated atrial fibrillation was followed up.

RESULTS

In the 142 patients with isolated atrial fibrillation, asMR was no/trivial in 55, mild in 83, moderate in 4, while none had severe asMR. Compared with controls and patients with no/trivial asMR, LV end-diastolic volume index was not increased and hemodynamic parameters were abnormal in patients with mild asMR (LV end-diastolic volume index, 65±6 versus 58±8 versus 60±8 mL/m²; stroke volume index, 42±4 versus 35±4 versus 29±6 mL/m²; P<0.001 versus other 2 groups; cardiac output index, 2.8±0.4 versus 2.8±0.5 versus 2.3±0.6 L/min per m²; P<0.001; systolic pulmonary artery pressure, 21±3 versus 26±5 versus 37±9 mm Hg; P<0.001). Although the event-free rate of HF symptomatic deterioration or hospitalization in patients with no/trivial asMR during a median 13.9 months follow-up was 86.9% and 100%, the rate in mild asMR was 59.4% and 85.0% (P<0.001 or P=0.032), respectively.

CONCLUSIONS

In the presence of isolated AF and no compensatory LV dilatation, impaired hemodynamics and higher risks of symptomatic HF deterioration were associated with mild asMR, requiring further studies of causalities.

Three-dimensional echocardiography reveals early mitral valve alterations in hypertrophic cardiomyopathy genetic mutation carriers

BACKGROUND

The mitral valve undergoes structural modifications in response to cardiac functional changes, often predating cardiac decompensation and overt clinical signs. Our study assessed the potential of mitral valve morphological changes as early indicators for detecting carriers of hypertrophic cardiomyopathy (HCM)-associated gene mutations.

METHODS

We studied 505 participants: 189 without the pathogenic gene mutations and left ventricular hypertrophy (G-/LVH-), 149 carriers without LV hypertrophy (G+/LVH-), and 167 manifest HCM patients (G+/LVH+). We juxtaposed the mitral valve morphology and associated metrics across these groups, emphasizing those carrying MYH7 and MYBPC3 mutations.

RESULTS

We discerned pronounced disparities in the mitral annulus and leaflet structures across the groups. The mitral valve apparatus in mutation carriers exhibited a tendency towards a flattened profile. Detailed analysis spotlighted MYBPC3 mutation carriers, whose mitral valves were notably flatter (with notably lower AHCWR values than non-carriers); this contrast was not evident in MYH7 mutation carriers. This mitral valve flattening, manifest in the mutation carriers, suggests it might be an adaptive response to incipient cardiac dysfunction in HCM's nascent stages.

CONCLUSIONS

Three-dimensional echocardiography illuminates the initial mitral valve structural changes in HCM patients bearing pathogenic gene mutations. These morphological signatures hold promise as sensitive imaging markers, especially for asymptomatic carriers of the MYBPC3 mutation.

Parameters of the mitral apparatus in patients with ischemic and nonischemic dilated cardiomyopathy

The mitral valve apparatus is a complex structure consisting of several coordinating components: the annulus, two leaflets, the chordae tendineae, and the papillary muscles. Due to the intricate interplay between the mitral valve and the left ventricle, a disease of the latter may influence the normal function of the former. As a consequence, valve insufficiency may arise despite the absence of organic valve disease. This is designated as functional or secondary mitral regurgitation, and it arises from a series of distortions to the valve components. This narrative review describes the normal anatomy and the pathophysiology behind the mitral valve changes in ischemic and non-ischemic dilated cardiomyopathies. It also explains the value of a complete multiparametric assessment of this structure. Not only must an assessment include quantitative measures of regurgitation, but also various anatomical parameters from the mitral apparatus and left ventricle, since they carry prognostic value and are predictors of mitral valve repair success and durability.

Mechanisms and implications of mitral regurgitation in patients with severe aortic stenosis who received transcatheter aortic valve replacement

INTRODUCTION

This study aimed to investigate the mechanisms and clinical implications of mitral regurgitation (MR) in patients with severe aortic stenosis (AS) who received transcatheter aortic valve replacement (TAVR).

METHODS

We conducted retrospective echocardiographic analyses at baseline and 6 months after TAVR in 140 patients with symptomatic AS (85 ± 5 years) who underwent TAVR. We defined significant MR as ≥ moderate based on evaluation of transthoracic echocardiography (TTE).

RESULTS

There were 48 patients (34%) with preexisting MR at the baseline. Among measured TTE parameters, end-systolic wall stress (ESWS), mitral annulus area, and mitral valve thickening index were independent factors associated with preexisting MR (odds ratio [OR]: 1.013, 95% confidence interval [CI]: 1.005-1.021; OR: 1.740, 95% CI: 1.314-2.376; OR: 2.306, 95% CI: 1.426-3.848; respectively). Six months after TAVR, there were 34 patients with post-existing MR, A history of atrial fibrillation and ESWS after TAVR were independent factors (OR: 3.013, 95% CI: 1.208-7.556; OR: 1.013, 95% CI: 1.000-1.023; respectively). The Kaplan-Meier plot indicated that preexisting MR was a risk factor for heart failure-related events within 1 year of discharge after TAVR (p = .012).

CONCLUSIONS

In patients who underwent TAVR for severe AS, preexisting MR was associated with having a thickened mitral valve and large mitral annulus size induced by high ESWS. These patients may have worse prognosis after TAVR and should be closely monitored in the long term.

New Perspective on Pathophysiology and Management of Functional Mitral Regurgitation

Functional mitral regurgitation (FMR) occurs as a result of global or segmental left ventricular (LV) dysfunction or left atrial dilatation, leading to mitral annular dilatation, papillary muscle displacement, mitral valve (MV) leaflet tethering, and leaflet remodeling. The prevalence of FMR continues to rise in the United States. Even mild FMR is associated with adverse clinical outcomes. Echocardiography is the primary imaging modality used to assess the type and severity of mitral regurgitation. FMR treatment depends on the etiology. Evidence-based pharmacologic and cardiac resynchronization therapies for underlying LV dysfunction remain the mainstay of treatment. Patients who remain symptomatic despite optimal medical therapy can be considered for surgical or percutaneous MV intervention. This article reviews the pathophysiology, imaging evaluation, and therapeutic options of FMR, highlighting the most recent developments in a rapidly evolving field.

Interaction between secondary mitral regurgitation and left atrial function and their prognostic implications after cardiac resynchronization therapy

AIMS

Left atrial (LA) function is a strong prognostic marker in patients with heart failure and functional mitral regurgitation (MR). Although cardiac resynchronization therapy (CRT) has shown to improve MR severity, the interaction between a reduction in MR severity and an increase in LA function, as well as its association with outcomes, has not been investigated.

METHODS AND RESULTS

LA reservoir strain (RS) was evaluated with speckle tracking echocardiography in patients with at least moderate functional MR undergoing CRT implantation. MR improvement was defined as at least 1 grade improvement in MR severity at 6 months after CRT implantation. The primary endpoint was all-cause mortality. A total of 340 patients (mean age 66 ± 10 years, 73% male) were included, of whom 200 (59%) showed MR improvement at 6 months follow-up. On multivariable analysis, an improvement in MR severity was independently associated with an increase in LARS (odds ratio 1.008; 95% confidence interval 1.003-1.013; P = 0.002). After multivariable adjustment, including baseline and follow-up variables, an increase in LARS was significantly associated with lower mortality. MR improvers showing LARS increasement had the lowest mortality rate, whereas outcomes were not significantly different between MR non-improvers and MR improvers showing no LARS increasement (P = 0.236).

CONCLUSION

A significant reduction in MR severity at 6 months after CRT implantation is independently associated with an increase in LARS. In addition, an increase in LARS is independently associated with lower all-cause mortality in patients with heart failure and significant functional MR.

Papillary Muscle Involvement during Acute Myocardial Infarction: Detection by Cardiovascular Magnetic Resonance Using T1 Mapping Technique and Papillary Longitudinal Strain

Papillary muscle (PPM) involvement in myocardial infarction (MI) increases the risk of secondary mitral valve regurgitation or PPM rupture and may be diagnosed using late gadolinium enhancement (LGE) imaging. The native T1-mapping (nT1) technique and PPM longitudinal strain (PPM-ls) have been used to identify PPM infarction (iPPM) without the use of the contrast agent. This study aimed to assess the diagnostic performance of nT1 and PPM-ls in the identification of iPPM. Forty-six patients, who performed CMR within 14-30 days after MI, were retrospectively enrolled: sixteen showed signs of iPPM on LGE images. nT1 values were measured within the infarcted area (IA), remote myocardium (RM), blood pool (BP), and anterolateral and posteromedial PPMs and compared using ANOVA. PPM-ls values have been assessed on cineMR images as the percentage of shortening between end-diastolic and end-systolic phases. Higher nT1 values and lower PPM-ls were found in infarcted compared to non-infarcted PPMs (nT1: 1219.3 ± 102.5 ms vs. 1052.2 ± 80.5 ms and 17.6 ± 6.3% vs. 21.6 ± 4.3%; p-value < 0.001 for both), with no significant differences between the nT1 of infarcted PPMs and IA and between the non-infarcted PPMs and RM. ROC analysis demonstrated an excellent discriminatory power for nT1 in detecting the iPPM (AUC = 0.874; 95% CI: 0.784-0.963; p < 0.001). nT1 and PPM-ls are valid tools in assessing iPPM with the advantage of avoiding contrast media administration.

NT-proBNP increase during stress echocardiography predicts significant changes in ischemic mitral regurgitation severity in patients qualified for surgical revascularization

BACKGROUND

In many patients, significant changes in ischemic mitral regurgitation (IMR) severity during exercise can be observed independent of the degree of IMR at rest. This study aimed to investigate the correlations between N-terminal fragment B-type natriuretic peptide (NT-proBNP) and echocardiography measurements at rest and at peak exercise in patients with moderate IMR who qualified for surgical revascularization.

METHODS

A total of 100 patients eligible for coronary artery bypass grafting, were included in this prospective study. All patients underwent exercise echocardiography. Additionally, the levels of NT-proBNP were measured at rest and after peak exercise.

RESULTS

A positive correlation of absolute NT-proBNP levels with effective regurgitant orifice area (EROA) were observed and with tricuspid regurgitant peak gradient (TRPG) at peak exercise. Absolute ΔNT-proBNP during exercise and the tenting area at rest were independent predictors of severe IMR at peak exercise. The level of absolute ΔNT-proBNP during exercise and coaptation height at rest were the most important predictors of significant increases in TRPG. The best cutoff value for ΔNT-proBNP as a predictor for increases in EROA at peak exercise was 68.9 pg/mL and to predict an increase in TRPG ≥ 50 mmHg at peak exercise was 68 pg/mL.

CONCLUSIONS

The level of ΔNT-proBNP during exercise was the most important parameter in predicting significant changes in IMR severity and pulmonary pressure. Based on the present data, it can be speculated that integration of the assessment of NT-proBNP at rest and at exercise might improve patient selection for valve surgery.

Functional anatomy and echocardiographic assessment in secondary mitral regurgitation

BACKGROUND

Mitral valve apparatus is complex and involves the mitral annulus, the leaflets, the chordae tendinae, the papillary muscles as well as the left atrial and ventricular myocardium. Secondary mitral regurgitation is a consequence of regional or global left ventricle remodeling due to an acute myocardial infarction (75% of cases) or idiopathic dilated cardiomyopathy (25% of cases). It is associated with an increase in mortality and poor outcome. There is a potential survival benefit deriving from the reduction in the degree of severity of mitral regurgitation. So the correction of the valve defect can change the clinical course and prognosis of the patient. The rationale for mitral valve treatment depends on the mitral regurgitation mechanism. Therefore, it is essential to identify and understand the pathophysiology of mitral valve regurgitation.

AIM OF THE STUDY

The aim of this review is to describe the crucial role of transthoracic and trans-esophageal echocardiography, in particular with three-dimensional echocardiography, for the assessment of the severity of secondary mitral regurgitation, anatomy, and hemodynamic changes in the left ventricle. Moreover, the concept that the mitral valve has no organic lesions has been abandoned. The echocardiography must allow a complete anatomical and functional evaluation of each component of the mitral valve complex, also useful to the surgeon in choosing the best surgical approach to repair the valve.

CONCLUSIONS

Echocardiography is the first-line imaging modality for a better selection of patients, according to geometrical modifications of mitral apparatus and left ventricle viability, especially in preoperative phase.

Analysis of changes in "mitral valve reserve" after coronary artery bypass grafts in patients with functional mitral regurgitation

INTRODUCTION

The treatment of moderate functionalmitral regurgitation (FMR) during coronary artery bypass grafting (CABG) is still debated. Our primary end point was to assess the improvement of "mitral valve reserve" (MVR) after CABG alone as a clinical demonstration of left ventricular (LV) recovery.

MATERIALS AND METHODS

Between June 2019 and June 2021, we prospectively enrolled 104 consecutive patients undergoing CABG with moderate FMR. Inclusion criteria were inferior-posterior-lateral wall hypokinesia and revascularization of the circumflex or right coronary artery. MVR was calculated as the ratio between anterior and posterior leaflets' straight length. All patients were followed for 1 year. The improvement of MVR has been considered as a reduction of the ratio between anterior and posterior leaflets straight length.

RESULTS

Compared to baseline, mean MVR was significantly reduced both at 6 (2.24 ± 0.95 vs. 1,91 ± 0.6; p = 0,047) and 12 months follow-up (2.24 ± 0.95 vs. 1,69 ± 0.49; p = 0,006). Left ventricular (LV) reverse remodeling, meant as improvement of LV ejection fraction and reduction of LV end-systolic volume index and mitral anulus diameter were evaluated at 6 months and 1 year. Mitral regurgitation grade were also significantly reduced at 6 months (p < .001).

CONCLUSION

The benefits of myocardial revascularization in term of improvement of mitral regurgitation's degree can be explained by the changes of MVR. The patients with FMR, who could have more advantages from CABG alone, should be the ones who have LVESVi just moderately increased.

Impact of secondary mitral valve chordal cutting on valve geometry in obstructive hypertrophic cardiomyopathy with marked septal hypertrophy

AIMS

In patients with obstructive hypertrophic cardiomyopathy (HCM) and mild septal thickness undergoing myectomy, resecting fibrotic anterior mitral leaflet (AML) secondary chordae moves the mitral valve (MV) away from the outflow tract and ejection flow, reducing the need for a deep septal excision. Aim of the present study was to assess whether chordal resection has similarly favourable effects in patients with important hypertrophy, who represent the majority of patients with obstructive HCM.

METHODS AND RESULTS

The MV position in the ventricular cavity, assessed from echocardiography as AML-annulus ratio, was compared before and after chordal resection in 150 consecutive HCM patients with important (≥20 mm) and 62 with mild (≤19 mm) septal thickness undergoing myectomy. Preoperatively, MV position was displaced towards the septum to a similar extent in both groups. Postoperatively, AML-annulus ratio increased of an equal degree in both groups, from 0.43 ± 0.05 to 0.55 ± 0.06 (P < 0.001) a 28% increase, and from 0.43 ± 0.06 to 0.55 ± 0.06 (P < 0.001) a 26% increase, respectively, indicating a similar MV shift away from the outflow tract. When AML-annulus ratio was compared in the study cohort and 124 normal subjects, MV position was within normal range in <4% of patients preoperatively and normalized in >50% postoperatively.

CONCLUSIONS

In obstructive HCM, displacement of the MV apparatus into the outflow tract interferes with the ejection flow. Resection of fibrotic secondary chordae moves the MV apparatus away from the outflow tract and enlarges the outflow area independently of septal thickness, facilitating septal myectomy by reducing the need for a deep muscular excision.

The Role of Cardiac Resynchronization Therapy for the Management of Functional Mitral Regurgitation

Valve leaflets and chordae structurally normal characterize functional mitral regurgitation (FMR), which in heart failure (HF) setting results from an imbalance between closing and tethering forces secondary to alterations in the left ventricle (LV) and left atrium geometry. In this context, FMR impacts the quality of life and increases mortality. Despite multiple medical and surgical attempts to treat FMR, to date, there is no univocal treatment for many patients. The pathophysiology of FMR is highly complex and involves several underlying mechanisms. Left ventricle dyssynchrony may contribute to FMR onset and worsening and represents an important target for FMR management. In this article, we discuss the mechanisms of FMR and review the potential therapeutic role of CRT, providing a comprehensive review of the available data coming from clinical studies and trials.

Segmentation of Echocardiography Based on Deep Learning Model

In order to achieve the classification of mitral regurgitation, a deep learning network VDS-UNET was designed to automatically segment the critical regions of echocardiography with three sections of apical two-chamber, apical three-chamber, and apical four-chamber. First, an expert-labeled dataset of 153 echocardiographic videos and 2183 images from 49 subjects was constructed. Then, the convolution layer in the VGG16 network was used to replace the contraction path in the original UNet network to extract image features, and depth supervision was added to the expansion path to achieve the segmentation of LA, LV, and MV. The results showed that the Dice coefficients of LA, LV, and MV were 0.935, 0.915, and 0.757, respectively. The proposed deep learning network can achieve simultaneous and accurate segmentation of LA, LV, and MV in multi-section echocardiography, laying a foundation for quantitative measurement of clinical parameters related to mitral regurgitation.

Right ventricular volume and its relationship to functional tricuspid regurgitation

Background

Significant right ventricular (RV) dilatation has long been considered integral to the pathogenesis of functional tricuspid regurgitation (FTR).

Objectives

To explore the relationship of RV dilatation and FTR in patients with ‘pure’ RV volume overload.

Methods

Patients (>17yrs) with RV dilatation due to pre-tricuspid shunts (atrial septal defect; ASD and/or partial anomalous pulmonary venous drainage; PAPVD) referred to our service (2000–2019) were retrospectively identified. Those with pulmonary hypertension, primum ASD or left-heart disease were excluded. Using standard cardiac MRI protocols, RV, right atrial and TV parameters were measured and compared.

Results

Of 52 consecutively eligible patients (42 ± 15yrs, 25 males), 25 had ASDs, 13 had PAPVD and 14 had both conditions. All were in sinus rhythm and none had pulmonary regurgitation. Left and right ventricular ejection fractions were normal (LVEF 63 ± 8%, RVEF 56 ± 8%). Indexed RV end-diastolic volumes (RVEDVi) were moderately increased (males 148 ± 33 mL/m² and females 141 ± 42 mL/m², range 95–267 mL/m²). Despite substantial RV volume overload, no patients had severe tricuspid regurgitation (TR). Only two had > mild TR. There was a weak correlation between tricuspid annular diameter and both degree of RV dilatation (r = 0.37; p = 0.01) and degree of TR (r = 0.38; p = 0.006). There was a similarly poor correlation between right atrial dimensions and the degree of TR (r = 0.34; p = 0.02).

Conclusion

When RV dilatation is simply due to volume overload, we find that significant TR is extremely rare. This gives an important and novel insight; that RV dilatation per se does not result in FTR.

Loss of left ventricular rotation is a significant determinant of functional mitral regurgitation

AIM

To evaluate insufficient rotational movement of the left ventricle (LV) as a potential novel mechanism for functional regurgitation of the mitral valve (FMR).

METHODS AND RESULTS

We compared reference subjects and patients with LV dysfunction (LVD, ejection fraction EF < 50%) with and without FMR (regurgitant volume RVol>10 ml). Subjects without structural mitral valve pathology undergoing cardiac MRI were evaluated. Delayed enhancement, global LV remodeling parameters, systolic twist and torsion were measured (using manual and novel automated cardiac MRI tissue-tracking). The study included 117 subjects with mean ± SD age 50.4 ± 17.8 years, of which 30.8% were female. Compared to subjects with LVD without FMR (n = 31), those with FMR (n = 37) had similar clinical characteristics, diagnoses, delayed enhancement, EF, and longitudinal strain. Subjects with FMR had significantly larger left ventricles (EDVi:136.6 ± 41.8 vs 97.5 ± 26.2 ml/m, p < 0.0001) with wider separation between papillary muscles (21.1 ± 7.6 vs 17.2 ± 5.7 mm, p = 0.023). Notably, they had lower apical (p < 0.0001) but not basal rotation and lower peak systolic twist (3.1 ± 2.4° vs 5.5 ± 2.5°, p < 0.0001) and torsion (0.56 ± 0.38°/cm vs 0.88 ± 0.52°/cm, p = 0.004). In a multivariate model for RVol including age, gender, twist, LV end-diastolic volume, sphericity index and separation between papillary muscles, only gender, volume and twist were significant. Twist was the most powerful correlate (beta -2.23, CI -3.26 to -1.23 p < 0.001). In patients with FMR, peak systolic twist negatively correlates with RVol (r = -0.73, p < 0.0001).

CONCLUSION

Reduced rotational systolic LV motion is significantly and independently associated with RVol among patients with FMR, suggesting a novel pathophysiological mechanism and a potential therapeutic target.

Echocardiographic Advances in Dilated Cardiomyopathy

Although the overall survival of patients with dilated cardiomyopathy (DCM) has improved significantly in the last decades, a non-negligible proportion of DCM patients still shows an unfavorable prognosis. DCM patients not only need imaging techniques that are effective in diagnosis, but also suitable for long-term follow-up with frequent re-evaluations. The exponential growth of echocardiography’s technology and performance in recent years has resulted in improved diagnostic accuracy, stratification, management and follow-up of patients with DCM. This review summarizes some new developments in echocardiography and their promising applications in DCM. Although nowadays cardiac magnetic resonance (CMR) remains the gold standard technique in DCM, the echocardiographic advances and novelties proposed in the manuscript, if properly integrated into clinical practice, could bring echocardiography closer to CMR in terms of accuracy and may certify ultrasound as the technique of choice in the follow-up of DCM patients. The application in DCM patients of novel echocardiographic techniques represents an interesting emergent research area for scholars in the near future.

Stress Echocardiography Protocol for Deciding Type of Surgery in Ischemic Mitral Regurgitation: Predictors of Mitral Regurgitation Recurrence following CABG Alone

Purpose: Although coronary artery bypass grafting alone (CABGa), or, with mitral annuloplasty (CABGmp), is considered the best therapeutic strategy for patients with ischemic mitral regurgitation (IMR), some recurrences are still reported. The aim of this study was to evaluate the use of the mitral deformation indices (MDI) as a predictor of recurrence of mitral regurgitation in a 12-month follow-up after CABG alone. Methods: A total of 145 patients after myocardial infarction with significant IMR, eligible for CABG, were prospectively enrolled in the study. Mitral valve morphology, left ventricle function, IMR degree as assessed by effective regurgitation orifice area (ERO), myocardial viability, and MDI were assessed prior to surgery. Patients were referred for CABGa (gr.1; n = 90) or CABGmp (gr.2; n = 55) based on clinical assessment, and the results of rest and stress echocardiography (exercise echocardiography and low dose dobutamine echocardiography-DBX). One year after surgery, each patient underwent the evaluation of cardiovascular events. Univariable logistic regression analysis was used to identify the factors of recurrence of IMR in 1 year follow-up. Serial echo examinations were performed in all patients at discharge, and at 1 and 12 months after surgery. Results: Logistic regression analysis revealed that in CABGa, group preoperative changes of tenting area (TA) and coaptation high (CH) during DBX remained the predictors of the recurrence of IMR in 12 months follow-up. TAdbx > 1 cm² provided a sensitivity of 90% and specificity of 29%, (AUC 0.6436). The best cut-off value for CHdbx was 0.4 cm (sensitivity 90%, specificity 34%; AUC 0.6432). In both groups (CABGa vs. CABGmp) no significant differences were observed in 12-month mortality (1.2% vs. 0%; p = 1.0), hospitalizations due to the heart failure (HF) exacerbation (5.9% vs. 8.5%; p = 0.72), and in the incidence of the composite endpoint (deaths/CV hosp/stroke) (7% vs. 8.5%; p = 0.742). Conclusions: The preoperative assessment of MDI changes during dbx can be used to identify patients with IMR qualified to CABG alone at increased risk of recurrence of IMR in 1 year follow-up. Mitral deformation analysis should be used for a better qualification of patients with IMR to the exact surgical approach.

Impact of aortic valve replacement for severe aortic stenosis on organic and functional mitral regurgitation

Aims

Concurrent mitral regurgitation (MR) influences treatment considerations in patients with severe aortic stenosis (sAS). Limited information exists regarding haemodynamic effects of sAS on MR severity and outcome of these patients. We assessed the impact of aortic valve replacement (AVR) on MR according to mechanism in patients with sAS and MR.

Methods and results

In patients with sAS who received surgical or transcatheter AVR from 2008 to 2017, those with effective mitral regurgitant orifice area (ERO) ≥ 10 mm² prior to AVR were evaluated. The change in MR after AVR was considered significant when there was at least one grade difference. We compared the all‐cause mortality of patients with and without improvement in MR. Of 234 patients with sAS and MR (age 80 ± 9 years, 52% male, ERO 19 ± 7 mm²), organic and functional MR were present in 166 (71%) and 68 (29%), respectively. MR improved in 136 (58%); improvement occurred with similar frequency in organic versus functional MR (59% and 57%, P = 0.88). Associated determinants were absence of atrial fibrillation in organic MR [odds ratio (OR) 2.09, 95% confidence interval (CI) 1.00–4.37; P = 0.049] and indexed aortic valve area (iAVA) ≤ 0.40 cm² in functional MR (OR 3.28, 95% CI 1.13–9.47; P = 0.028). In the overall cohort, mitral annulus diameter < 3 cm (OR 1.74, 95% CI 1.02–2.97; P = 0.041) and QRS duration < 115 ms (OR 1.73, 95% CI 1.00–2.98; P = 0.049) were independently associated with improvement in MR. During median follow‐up of 3.5 years, lack of improvement in MR was not associated with higher mortality in the overall cohort of patients with ERO ≥ 20 mm² [adjusted hazard ratio (HR) 1.71, 95% CI 0.90–3.27; P = 0.10, adjusted for age, New York Heart Association III or IV, diabetes, and creatinine ≥ 2.0 mg/dL]. Lack of improvement in organic MR was associated with higher mortality (adjusted HR 3.36, 95% CI 1.40–8.05; P < 0.01). In patients with functional MR, change in MR was not associated with mortality (HR 1.24, 95% CI 0.44–3.47; P = 0.68).

Conclusions

In nearly 60% of patients with sAS and MR, MR improved after AVR, even in the majority of patients with organic MR. Absence of atrial fibrillation in organic MR, iAVA ≤ 0.40 cm² in functional MR, and mitral annulus diameter < 3 cm and QRS duration < 115 ms in the overall population were associated with MR improvement. Post‐operative improvement in organic MR was associated with better survival.

Differences in mitral valve geometry between atrial and ventricular functional mitral regurgitation in patients with atrial fibrillation: a 3D transoesophageal echocardiography study

AIMS

This study investigated geometric differences in mitral valve apparatus between atrial functional mitral regurgitation (A-FMR) and functional mitral regurgitation (FMR) with left ventricular (LV) dysfunction in patients with atrial fibrillation (AF) using 3D transoesophageal echocardiography (TOE).

METHODS AND RESULTS

In total, 135 moderate or greater FMR patients with persistent AF or atrial flutter underwent 3D TOE. Fifty-six patients had A-FMR, defined as preserved LV ejection fraction (LVEF) of ≥50% and normal LV wall motion. Seventy-nine patients had ventricular FMR (V-FMR), defined as LV dysfunction (LVEF of <50%) or LV wall motion abnormality. To evaluate mitral leaflet coaptation, the coapted area was calculated as follows: total leaflet area (TLA) in end-diastole - closed leaflet area in mid-systole. Although annular area (AA) did not significantly differ between the two groups, TLA was significantly smaller in A-FMR than in V-FMR (P = 0.005). TLA/AA, indicating the degree of the leaflet remodelling, was significantly smaller in A-FMR than in V-FMR (P < 0.001). A-FMR had significantly smaller posterior mitral leaflet tethering height and angle measured at three anteroposterior planes (lateral, central, and medial) than V-FMR (all P < 0.001). However, vena contracta width (VCW) measured on long-axis view on TOE and coapted area, which correlated with VCW (r = -0.464, P < 0.001), were similar between the two groups.

CONCLUSION

Mitral leaflet remodelling may be less in A-FMR compared with V-FMR. However, leaflet tethering was smaller in A-FMR than in V-FMR, and this may result in a similar degree of mitral leaflet coaptation and mitral regurgitation severity.

Outcome of consistent guideline-based tricuspid management in patients undergoing degenerative mitral regurgitation correction

Objectives

Despite coherent guidelines, management of functional tricuspid regurgitation (FTR) consequences on outcome in the context of degenerative mitral regurgitation (DMR) remains controversial due to lacking series of large magnitude with rigorous application of tricuspid guidelines and strict long-term echocardiographic follow-up. Thus, we aimed at gathering such a cohort to examine outcomes of patients undergoing DMR surgery following tricuspid surgery guidelines.

Methods

All consecutive patients with isolated DMR 2005-2015 operated on with baseline FTR assessment and tricuspid annulus diameter measurement were identified. Operative complications, postoperative tricuspid regurgitation incidence, and survival were assessed overall and stratified by guideline-based tricuspid annuloplasty (TA) indication (severe FTR or tricuspid annulus diameter ≥40 mm).

Results

Among 441 patients with DMR undergoing mitral repair (66 ± 13 years, 30% female, ejection fraction 66 ± 10%, systolic pulmonary artery pressures 39 ± 12 mm Hg) followed 6 [3-9] years, patients with TA (n = 234, 53%) had generally similar presentation versus without TA (n = 207, 47%; all P ≥ .2) except for more atrial fibrillation and larger left ventricle (both P ≥ .0003). Patients with TA showed longer bypass time, more maze procedures (all P ≤ .001), but hospital stay, renal-failure, pacemaker implantation, and operative mortality (overall 0.9%) were comparable (all P ≥ .2). Postoperative incidence of moderate/severe FTR (0% at 1 year) became over time greater among patients without TA (5-year 8% [4%-13%] vs 3% [1%-11%] and 10-year 10% [6%-16%] vs 4% [1%-16%], P = .01). Survival (95% confidence interval) throughout follow-up was 85% (77%-89%) at 10 years, with hazard ratio 0.57 (0.29-1.10), P = .09. for patients with TA versus without.

Conclusions

In this large surgical DMR cohort, guideline-based FTR management was safe and effective. While long-term mortality did not reach significance, postoperative incidence of moderate/severe FTR, overall low, was nevertheless greater in patients who did not appear to require TA at surgery and linked to tricuspid annular dimension. Thus, future multicenter prospective cohorts with long-term follow-up are warranted to re-examine thresholds for TA performance and impact on survival.

Principal Morphomic and Functional Components of Secondary Mitral Regurgitation

OBJECTIVES

The aim of this work was to identify the key morphological and functional features in secondary mitral regurgitation (sMR) and their prognostic impact on outcome.

BACKGROUND

Secondary sMR in patients with heart failure and reduced ejection fraction typically results from distortion of the underlying cardiac architecture. The morphological components which may account for the clinical impact of sMR have not been systematically assessed or correlated with clinical outcomes.

METHODS

Morphomic and functional network profiling were performed on a cohort of patients with stable heart failure optimized on guideline-based medical therapy. Principal component (PC) analysis and subsequent cluster analysis were used to condense the morphomic and functional data first into PCs with varimax rotation (PC_Vmax) and second into homogeneous clusters. Clusters and PCs were tested for their correlations with clinical outcomes.

RESULTS

Morphomic and functional data from 383 patients were profiled and subsequently condensed into PCs. PC_Vmax 1 describes high loadings of left atrial morphological information, and PC_Vmax 2 describes high loadings of left ventricular (LV) topology. Based on these components, 4 homogeneous clusters were derived. sMR was most prominent in clusters 3 and 4, with the morphological difference being left ventricular size (median end-diastolic volume 188 mL [interquartile range: 160 mL-224 mL] vs 315 mL [264 mL-408 mL]; P < 0.001). Clusters were associated with mortality (P < 0.001), but sMR remained independently associated with mortality after adjusting for the clusters (adjusted HR: 1.42; 95% CI: 1.14-1.77; P < 0.01). The detrimental association of sMR with mortality was mainly driven by cluster 3 (HR: 2.18; 95% CI: 1.32-3.60; P = 0.002), the "small LV cavity" phenotype.

CONCLUSIONS

These results challenge the current perceptions that sMR in heart failure with reduced ejection fraction results exclusively from global or local LV remodeling and are suggestive of a potential role of the left atrial component. The association of sMR with mortality cannot be purely attributed to cardiac morphology alone, supporting other complementary key aspects of mitral valve closure consistent with the force balance theory. Unsupervised clustering supports the association of sMR with mortality predominantly driven by the small LV cavity phenotype, as previously suggested by a conceptional framework and termed disproportionate sMR.

Mitral Valvular Coaptation-Zone Area Is Associated with the Severity of Atherosclerosis Assessed by Cardio-Ankle Vascular Index

Preservation of the mitral valve (MV) size is essential for valve function, and a reduced MV coaptation-zone area increases the risk of developing functional mitral regurgitation (FMR). We aimed to determine if the MV leaflet and coaptation-zone areas were associated with the severity of atherosclerosis assessed by cardio-ankle vascular index (CAVI) in patients with normal left ventricle (LV) systolic function and size by real-time 3D echocardiography (RT3DE).We performed RT3DE analysis in 66 patients with normal LV size and ejection fraction who underwent 2D echocardiography and CAVI. MV coaptation-zone areas were measured by custom 3D software and indexed by body surface area (BSA). The associations of clinical factors and mean CAVI with MV leaflet and coaptation-zone areas were evaluated by univariable and multivariable linear regression analyses.On univariable analysis, MV leaflet area/BSA was significantly associated with age (r = -0.335, P = 0.0069) and mean CAVI (r = -0.464, P < 0.001), and MV coaptation-zone area was significantly associated with age (r = -0.626, P < 0.001), hypertension (r = -0.626, P < 0.001), dyslipidemia (r = -0.626, P < 0.001), E/e' (r = -0.626, P < 0.001), and CAVI (r = -0.740, P < 0.001). On multivariable analysis, mean CAVI was independently associated only with MV leaflet area/BSA (standardized coefficient = -0.611, P < 0.001) and MV coaptation-zone area/BSA (standardized coefficient = -0.74, P < 0.001).In patients with normal LV systolic function and size, MV leaflet and coaptation-zone areas might be reduced according to advancing atherosclerosis. Patients with atherosclerosis might be at increased risk of developing FMR.

Secondary valve regurgitation in patients with heart failure with preserved ejection fraction, heart failure with mid-range ejection fraction, and heart failure with reduced ejection fraction

Secondary mitral regurgitation and secondary tricuspid regurgitation due to heart failure (HF) remain challenging in almost every aspect: increasing prevalence, poor prognosis, notoriously elusive in diagnosis, and complexity of therapeutic management. Recently, defined HF subgroups according to three ejection fraction (EF) ranges (reduced, mid-range, and preserved) have stimulated a structured understanding of the HF syndrome but the role of secondary valve regurgitation (SVR) across the spectrum of EF remains undefined. This review expands this structured understanding by consolidating the underlying phenotype of myocardial impairment with each type of SVR. Specifically, the current understanding, epidemiological considerations, impact, public health burden, mechanisms, and treatment options of SVR are discussed separately for each lesion across the HF spectrum. Furthermore, this review identifies important gaps in knowledge, future directions for research, and provides potential solutions for diagnosis and treatment. Mastering the challenge of SVR requires a multidisciplinary collaborative effort, both, in clinical practice and scientific approach to optimize patient outcomes.

Echocardiographic assessment of mitral regurgitation: discussion of practical and methodologic aspects of severity quantification to improve diagnostic conclusiveness

The echocardiographic assessment of mitral valve regurgitation (MR) by characterizing specific morphological features and grading its severity is still challenging. Analysis of MR etiology is necessary to clarify the underlying pathological mechanism of the valvular defect. Severity of mitral regurgitation is often quantified based on semi-quantitative parameters. However, incongruent findings and/or interpretations of regurgitation severity are frequently observed. This proposal seeks to offer practical support to overcome these obstacles by offering a standardized workflow, an easy means to identify non-severe mitral regurgitation, and by focusing on the quantitative approach with calculation of the individual regurgitant fraction. This work also indicates main methodological problems of semi-quantitative parameters when evaluating MR severity and offers appropriateness criteria for their use. It addresses the diagnostic importance of left-ventricular wall thickness, left-ventricular and left atrial volumes in relation to disease progression, and disease-related complaints to improve interpretation of echocardiographic findings. Finally, it highlights the conditions influencing the MR dynamics during echocardiographic examination. These considerations allow a reproducible, verifiable, and transparent in-depth echocardiographic evaluation of MR patients ensuring consistent haemodynamic plausibility of echocardiographic results.

Secondary mitral regurgitation-Insights from microRNA assessment

BACKGROUND

While secondary mitral regurgitation (sMR) is associated with adverse outcome in heart failure with reduced ejection fraction (HFrEF), key pathophysiologic mechanisms remain poorly understood and might be elucidated by microRNAs (miRNA/miR), that were recently related to cardiac remodelling. This study sought to assess (i) the differences of miRNA profiles in patients with severe sMR compared to matched disease controls, (ii) the correlation between circulating miRNAs and surrogates of sMR severity as well as (iii) the prognostic implications of miRNA levels in severe sMR.

MATERIALS AND METHODS

Sixty-six HFrEF patients were included, of these 44 patients with severe sMR 2:1 matched to HFrEF controls with no/mild sMR. A comprehensive set of miRNAs (miR-21, miR-29a, miR-122, miR-132, miR-133a, miR-let7i) were measured and correlated to echocardiographic sMR severity.

RESULTS

miRNA patterns differed distinctly between patients with severe sMR and HFrEF controls (P < .05). Among the panel of assessed miRNAs, miR-133a correlated most strongly with surrogates of sMR severity (r = -0.41, P = .001 with sMR vena contracta width). Interestingly, elevated levels of miR-133 were associated with an increased risk for cardiovascular death and/or HF hospitalizations with and adjusted HR of 1.85 (95% CI 1.24-2.76, P = .003).

CONCLUSIONS

This study unveils distinct pathophysiologic maladaptions at a cellular level in patients with severe sMR compared to no/mild sMR by showing significant differences in miRNA profiles and correlations with sMR severity, supporting the concept that sMR drives cardiac remodelling in heart failure. Moreover, the increased risk for adverse outcome in HFrEF patients with severe sMR conveyed by miR-133a might indicate irreversible myocardial damage.

Predicting clinical outcome by indexed mitral valve tenting in functional mitral valve regurgitation

OBJECTIVES

Mitral valve (MV) tenting parameters are indicators of left ventricular remodelling severity and may predict outcome in functional mitral regurgitation (FMR). We hypothesised that indexing of MV tenting area to body surface area (BSA), to mitral annulus diameter or gender-adjusted analysis of tenting parameters may improve their prognostic value.

METHODS

We identified retrospectively 240 patients with consecutive FMR (mean age 68±10 years; men=135) from our institutional database who underwent isolated MV annuloplasty during a period of 7 years (2010-2016). Using preoperative two-dimensional transthoracic echocardiographic images, MV tenting parameters including tenting area, tenting height and annulus diameter were systematically assessed. Follow-up protocol consisted of chart review and structured clinical questionnaire. Primary study endpoint was the composite of death and adverse cardiac events (ie, MV reoperation, cardiac resynchronisation therapy implantation, ventricular assist device implantation or heart transplantation).

RESULTS

BSA-indexed MV tenting area was identified as independent predictor of primary study endpoint (HR 1.9; 95% CI 1.1 to 3.5; p=0.02). After cut-off point analysis, BSA-indexed MV tenting area >1.35 cm²/m² was significantly associated with primary study outcome (HR 2.3; 95% CI 1.3 to 4.0; p=0.003). Annulus-indexed MV tenting area showed only a tendency towards primary study endpoint prediction (HR 2.8; 95% CI 0.6 to 12.6; p=0.17). Between female and male patients, BSA-indexed MV tenting area was similar (1.42±0.4 cm²/m² vs 1.45±0.4cm²/cm²; p=0.6) and gender was not associated with primary study outcome (HR 0.8; 95% CI 0.5 to 1.4; p=0.5).

CONCLUSION

In our FMR cohort, BSA-indexed MV tenting area showed the strongest association with negative outcomes following isolated MV annuloplasty. Patients with BSA-indexed MV tenting area >1.35cm²/m² could potentially benefit from additional surgical maneuvers addressing left ventricular remodelling.

Relationship Between Mitral Leaflet Size and Coaptation and Their Associated Factors in Patients with Normal Left Ventricular Size and Systolic Function

Enlargement of the mitral valve (MV) has gained attention as a compensatory mechanism for functional mitral regurgitation (FMR). We aimed to determine if MV leaflet area is associated with MV coaptation-zone area and identify the clinical factors associated with MV leaflet size and coaptation-zone area in patients with normal left ventricle (LV) systolic function and size using real-time 3D echocardiography (RT3DE).We performed RT3DE in 135 patients with normal LV size and ejection fraction. MV leaflet and coaptation-zone areas were measured using custom 3D software. The clinical factors associated with MV leaflet and coaptation-zone areas were evaluated using univariate and multivariate linear regression analyses.There was a significant relationship between MV leaflet and coaptation-zone areas (r = 0.499, P < 0.001). MV leaflet area was strongly associated with body surface area (BSA) (r = 0.905, P < 0.001) rather than LV size and age. MV leaflet area/BSA was independently associated with male gender (P = 0.002), lower diastolic blood pressure (P = 0.042), and LV end-diastolic volume (LVEDV) index (P = 0.048); MV coaptation-zone area/BSA was independently associated with lower LVEDV index (P = 0.01).In patients with normal LV systolic function and size, MV leaflet size has a significant impact on competent MV coaptation. MV leaflet area might be intrinsically determined by body size rather than age and LV size, and the MV leaflet area/BSA is relatively constant. On the other hand, some clinical factors might also influence MV leaflet and coaptation-zone area.

A new disease entity: Atrial functional mitral regurgitation

Functional mitral regurgitation (MR) has been traditionally known as secondary MR resulting from left ventricular (LV) dilatation and systolic dysfunction. However, deterioration of functional MR also relates to mitral annular (MA) dilatation. Furthermore, MA dilatation due to left atrial dilatation in patients with atrial fibrillation (AF) can also cause functional MR, even in the absence of LV systolic dysfunction, in a condition referred to as "atrial functional MR" (AFMR). AFMR also has other etiological factors, including disruption of the MA saddle shape, reduction in MA contractility, inadequate compensation for the MA dilatation resulting from the lack of leaflet remodeling, and hamstringing of the posterior mitral leaflet by atriogenic tethering. AFMR has recently received much attention as an important cause of heart failure, and it represents a considerable therapeutic target in heart failure patients with AF. The traditional functional MR occurring in patients with LV dilatation and systolic dysfunction has since been designated "ventricular functional MR" (VFMR) to distinguish it from AFMR. This review article compares the current perceptions of newly recognized AFMR with those of traditional VFMR.

Causes and mechanisms of isolated mitral regurgitation in the community: clinical context and outcome

AIMS

To define the hitherto unknown aetiology/mechanism distributions of mitral regurgitation (MR) in the community and the linked clinical characteristics/outcomes.

METHODS AND RESULTS

We identified all isolated, moderate/severe MR diagnosed in our community (Olmsted County, MN, USA) between 2000 and 2010 and classified MR aetiology/mechanisms. Eligible patients (n = 727) were 73 ± 18 years, 51% females, with ejection fraction (EF) 49 ± 17%. MR was functional (FMR) in 65%, organic (OMR) in 32% and 2% mixed. Functional MR was linked to left ventricular remodelling (FMR-v) 38% and isolated atrial dilatation (FMR-a) 27%. At diagnosis FMR-v vs. FMR-a, vs. OMR displayed profound differences (all P < 0.0001) in age (73 ± 14, 80 ± 10, 68 ± 21years), male-sex (59, 33, 51%), atrial-fibrillation (28, 54, 13%), EF (33 ± 14, 57 ± 11, 61 ± 10%), and regurgitant-volume (38 ± 13, 37 ± 11, 51 ± 24 mL/beat). Dominant MR mechanism was Type I (normal valve-movement) 38%, Type II (excessive valve-movement) 25%, Type IIIa (diastolic movement-restriction) 3%, and Type IIIb (systolic movement-restriction) 34%. Outcomes were mediocre with excess-mortality vs. general-population in FMR-v [risk ratio 3.45 (2.98-3.99), P < 0.0001] but also FMR-a [risk ratio 1.88 (1.52-2.25), P < 0.0001] and OMR [risk ratio 1.83 (1.50-2.22), P < 0.0001]. Heart failure was frequent, particularly in FMR-v (5-year 83 ± 3% vs. 59 ± 4% FMR-a, 40 ± 3% OMR, P < 0.0001). Mitral surgery during patients' lifetime was performed in 4% of FMR-v, 3% of FMR-a, and 37% of OMR.

CONCLUSION

Moderate/severe isolated MR in the community displays considerable aetiology/mechanism heterogeneity. Functional MR dominates, mostly FMR-v but FMR-a is frequent and degenerative MR dominates OMR. Outcomes are mediocre with excess-mortality particularly with FMR-v but FMR-a, despite normal EF incurs notable excess-mortality and frequent heart failure. Pervasive undertreatment warrants clinical trials of therapies tailored to specific MR cause/mechanisms.

Prognostic value of mitral valve tenting area in patients with functional mitral regurgitation

OBJECTIVES

Mitral valve (MV) repair in functional mitral regurgitation is still associated with suboptimal outcomes. Our goal was to determine whether the clinical outcome following MV repair correlates with preoperative tenting parameters.

METHODS

We retrospectively identified consecutive patients with functional mitral regurgitation who underwent an isolated MV annuloplasty during a 7-year period (2010-2016) from our institutional database. Preoperative tenting parameters (i.e. tenting height, coaptation length, tenting area, posterior mitral leaflet and anterior mitral leaflet angles and interpapillary muscle distance) were systematically measured. The primary end point was the composite of survival and freedom from adverse cardiac events. The follow-up protocol consisted of a structured clinical questionnaire and an analysis of the echocardiographic data.

RESULTS

A total of 240 patients (mean age 67.8 ± 9.8 years, 57% of men) were analysed. The overall 5-year survival rate for the whole study cohort was 74.7 ± 4.2%, and freedom from adverse cardiac events was 84.8 ± 3.4%. A tenting area ≥2.4 cm2 was identified as a cut-off value, independently predicting the composite primary study end point (hazard ratio 2.0; P = 0.03). Furthermore, a Kaplan-Meier analysis revealed a strong tendency towards worse 5-year outcomes in patients with a tenting area ≥2.4 cm2 (n = 153) versus patients with a tenting area <2.4 cm2 (n = 87) (65.3 ± 5.5% vs 77.1 ± 6.3%; P = 0.06).

CONCLUSIONS

MV annuloplasty is associated with acceptable clinical and echocardiographic outcomes in patients with functional mitral regurgitation 5 years postoperatively. A preoperative tenting area ≥2.4 cm2 showed a strong trend towards a worse 5-year survival rate and an increased risk of adverse cardiac events after an isolated MV annuloplasty.

Impact of Mitral Regurgitation Severity and Left Ventricular Remodeling on Outcome After MitraClip Implantation: Results From the Mitra-FR Trial

OBJECTIVES

This study aimed to identify a subset of patients based on echocardiographic parameters who might have benefited from transcatheter correction using the MitraClip system in the MITRA-FR (Percutaneous Repair with the MitraClip Device for Severe Functional/Secondary Mitral Regurgitation) trial.

BACKGROUND

It has been suggested that differences in the degree of mitral regurgitation (MR) and left ventricular (LV) remodeling may explain the conflicting results between the MITRA-FR and the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation) trials.

METHODS

In a post hoc analysis, we evaluated the interaction between the intervention and subsets of patients defined based on MR severity (effective regurgitant orifice [ERO], regurgitant volume [RVOL] and regurgitant fraction [RF]), LV remodeling (end-diastolic and end-systolic diameters and volumes) and combination of these parameters with respect to the composite of death from any cause or unplanned hospitalization for heart failure at 24 months.

RESULTS

We observed a neutral impact of the intervention in subsets with the highest MR degree (ERO ≥30 mm², RVOL ≥45 ml or RF ≥50%) as in patients with milder MR degree. The same was seen in subsets with the milder LV remodeling using either diastolic or systolic diameters or volumes. When parameters of MR severity and LV remodeling were combined, there was still no benefit of the intervention including in the subset of patients with an ERO/end-diastolic volume ratio ≥ 0.15 despite similar ERO and LV end-diastolic volume compared with COAPT patients.

CONCLUSIONS

In the MITRA-FR trial, we could not identify a subset of patients defined based on the degree of the regurgitation, LV remodeling or on their combination, including those deemed as having disproportionate MR, that might have benefited from transcatheter correction using the MitraClip system. (Multicentre Study of Percutaneous Mitral Valve Repair MitraClip Device in Patients With Severe Secondary Mitral Regurgitation [MITRA-FR]; NCT01920698).

Attenuated Mitral Leaflet Enlargement Contributes to Functional Mitral Regurgitation After Myocardial Infarction

BACKGROUND

Mitral leaflet enlargement has been identified as an adaptive mechanism to prevent mitral regurgitation in dilated left ventricles (LVs) caused by chronic aortic regurgitation (AR). This enlargement is deficient in patients with functional mitral regurgitation, which remains frequent in the population with ischemic cardiomyopathy. Maladaptive fibrotic changes have been identified in post-myocardial infarction (MI) mitral valves. It is unknown if these changes can interfere with valve growth and whether they are present in other valves.

OBJECTIVES

This study sought to test the hypothesis that MI impairs leaflet growth, seen in AR, and induces fibrotic changes in mitral and tricuspid valves.

METHODS

Sheep models of AR, AR + MI, and controls were followed for 90 days. Cardiac magnetic resonance, echocardiography, and computed tomography were performed at baseline and 90 days to assess LV volume, LV function, mitral regurgitation and mitral leaflet size. Histopathology and molecular analyses were performed in excised valves.

RESULTS

Both experimental groups developed similar LV dilatation and dysfunction. At 90 days, mitral valve leaflet size was smaller in the AR + MI group (12.8 ± 1.3 cm² vs. 15.1 ± 1.6 cm², p = 0.03). Mitral regurgitant fraction was 4% ± 7% in the AR group versus 19% ± 10% in the AR + MI group (p = 0.02). AR + MI leaflets were thicker compared with AR and control valves. Increased expression of extracellular matrix remodeling genes was found in both the mitral and tricuspid leaflets in the AR + MI group.

CONCLUSIONS

In these animal models of AR, the presence of MI was associated with impaired adaptive valve growth and more functional mitral regurgitation, despite similar LV size and function. More pronounced extracellular remodeling was observed in mitral and tricuspid leaflets, suggesting systemic valvular remodeling after MI.

Potential mechanism of left ventricular spherical remodeling: association of mitral valve complex-myocardium longitudinal tissue remodeling mismatch

Since mitral valve (MV) complex (MVC) longitudinally bridges left ventricular (LV) base end and its middle, insufficient MVC longitudinal tissue length (TL) elongation relative to whole LV myocardial longitudinal TL elongation could limit LV-base-longitudinal-TL elongation, leading to predominant LV-base-transverse-TL elongation, constituting LV spherical remodeling. In 30 patients with dilated cardiomyopathy (DCM), 30 with aortic regurgitation (AR), and 30 controls, LV sphericity, LV-apex- or base-transverse- and longitudinal-TL, MVC-longitudinal-TL, and whole-LV-longitudinal-TL were measured by three-dimensional (3D) echocardiography. Ratio of each measure versus mean normal value (i.e., LV-apex-transverse-TL ratio) was considered to express the directional and regional tissue elongation. [LV-base-longitudinal-TL ratio/global-LV-TL ratio] and [MVC-longitudinal-TL ratio/whole-LV-longitudinal-TL ratio] were obtained as the degree of LV-base-longitudinal-TL or MVC-longitudinal-TL elongation relative to the whole LV elongation. LV-apex-transverse-, LV-apex-longitudinal-, and LV-base-transverse-TL ratios were significantly increased (1.27 to 1.42, P < 0.01) in both DCM and AR, while the LV-base-longitudinal-TL ratio was not increased in DCM [1.04 ± 0.19, not significant (ns)] and only modestly increased in AR (1.12 ± 0.21, P < 0.01). Whole-LV-longitudinal-TL ratio was significantly increased in both DCM and AR (1.22 ± 0.18 and 1.20 ± 0.16, P < 0.01), while MVC-longitudinal-TL ratio was not or only modestly increased in both groups (1.07 ± 0.15, ns, and 1.12 ± 0.17, P = 0.02, respectively). Multivariable analysis revealed that LV sphericity was independently related to a reduced [LV-base-longitudinal-TL ratio/global-LV-TL ratio] (standard β = -0.42, P < 0.01), which was further related to a reduced [MVC-longitudinal-TL ratio/whole-LV-longitudinal-TL ratio] (standard β = 0.72, P < 0.01). These are consistent with the hypothesis that relatively less MVC-longitudinal-TL elongation in the process of primary LV myocardial tissue elongation may limit LV-base-longitudinal-TL elongation, contributing to LV spherical remodeling.NEW & NOTEWORTHY Left ventricular (LV) spherical remodeling is associated with poor prognosis and less-effective cardiac performance, which commonly develops in dilated cardiomyopathy. However, its mechanism remains unclear. We hypothesized and subsequently clarified that less mitral valve complex (MVC) tissue longitudinal elongation relative to whole LV myocardial tissue longitudinal elongation is related to disproportionately less LV base longitudinal versus transverse myocardial tissue elongation, constituting spherical remodeling. This study suggests modification of MVC tissue elongation could be potential therapeutic targets.

Relation of Mitral Annulus and Left Atrial Dysfunction to the Severity of Functional Mitral Regurgitation in Patients with Dilated Cardiomyopathy

METHODS

56 patients (58 ± 17 years, 42 men) with DCM and FMR and 52 controls, prospectively enrolled, underwent 3DTTE dedicated for mitral valve (MV), LA, and left ventricle (LV) quantitative analysis.

RESULTS

Patients with FMR vs. controls presented increased MA size and sphericity during the entire systole, whereas MA fractional area change (MAFAC) and MA displacement were decreased (15 ± 5 vs. 28 ± 5%; and 5 ± 3 vs. 10 ± 2 mm, p < 0.001). In patients with moderate/severe FMR, MA diameters correlated with PISA radius, EROA, and regurgitant volume (Rvol), as also did the MA area (with PISA radius, EROA, and Rvol: r = 0.48, r = 0.58, and r = 0.47, p < 0.05). MAFAC correlated inversely with EROA and Rvol (r = -0.32 and r = -0.35, p < 0.05), with both active and total LA emptying fractions and with LV ejection fraction as well. In a stepwise multivariate regression model, decreased MAFAC and increased LA volume independently predicted patients with severe FMR.

CONCLUSIONS

Patients with DCM and FMR have MA geometry remodeling and contractile dysfunction, correlated with the severity of FMR. MA contractile dysfunction correlated with both LA and left LV pumps dysfunctions and predicted patients with severe FMR. Our results provide new insights that might help with better selection of patients for MV transcatheter procedures.

Atrial functional mitral regurgitation: mechanisms and surgical implications

The term atrial functional mitral regurgitation refers to a newly recognized disease entity in which mitral regurgitation occurs secondary to left atrial disease, without left ventricular dilatation and intrinsic mitral valve disease, typically in the setting of long-standing atrial fibrillation. Recent evidence suggests that atrial functional mitral regurgitation is associated with increased risk of death and heart failure re-hospitalization. The etiology, pathophysiology, and mechanism of atrial functional mitral regurgitation is not completely understood but they should not be regarded as the same as for the conventional type of functional mitral regurgitation secondary to left ventricular dilatation and dysfunction. Mitral annular dilatation, atriogenic leaflet distortion, insufficient leaflet remodeling, and subtle left ventricular dysfunction may play a role in the pathogenesis of atrial functional mitral regurgitation. The therapeutic and surgical considerations of atrial functional mitral regurgitation are different from those of ventricular functional mitral regurgitation. In this review, we assess current evidence regarding this new disease entity and propose a new surgical approach based on up-to-date understanding and experience of this condition.

Outcome comparison of mitral valve surgery and MitraClip therapy in patients with severely reduced left ventricular dysfunction

Aims

The aim of this study was to compare the outcomes of surgical mitral valve repair or replacement (sMVR) and percutaneous edge‐to‐edge repair using MitraClip (pMVR) in patients with severe left ventricular dysfunction affected by functional mitral regurgitation (FMR).

Methods and results

We retrospectively identified 132 patients with left ventricular ejection fraction (LVEF) ≦ 30% submitted to sMVR (n = 47) or pMVR (n = 85) for FMR at our centre from January 2013 to December 2017. To adjust for baseline imbalances, we used a propensity score matching by age, logistic EuroSCORE, and left ventricular end‐systolic volume. After being matched, MitraClip therapy showed lower perioperative mortality and rate of complications yet increased residual mitral regurgitation (MR) grade than did surgery (0.2 ± 0.50 in sMVR vs. 1.3 ± 0.88 in pMVR, P < 0.0001). According to stratified multivariate Cox model analysis, residual MR severity was an independent risk factor for cardiac death [hazard ratio (HR), 2.81; 95% confidence interval [CI], 1.44–5.48, P = 0.0025] and re‐hospitalization for heart failure (HR, 3.07; 95% CI, 1.50–6.29, P = 0.0022) at 1 year follow‐up. Stratified multivariable Cox regression analysis at 3 years identified pMVR as risk factor for cardiac death (HR, 0.19; 95% CI, 0.040–0.86, P = 0.031) and re‐hospitalization for heart failure (HR, 0.28; 95% CI, 0.077–0.99, P = 0.048).

Conclusions

In patients with FMR and LVEF ≤ 30%, MitraClip therapy resulted in lower perioperative complications and mortality than sMVR. However, surgically treated patients who survived the perioperative stage had less residual MR and experienced lower rates of re‐hospitalization for heart failure at 1 year and lower cardiac mortality at 1 and 3 years of follow‐up than did patients undergoing pMVR.

Higher preoperative left atrial volume index predicts lack of mitral regurgitation improvement after transcatheter aortic valve replacement

BACKGROUND

Moderate-to-severe mitral regurgitation is present in 20-35% of patients undergoing transcatheter aortic valve replacement (TAVR) and the current literature lacks simple echocardiographic parameters, which can predict post-TAVR changes in mitral regurgitation. The aim of this study is to investigate the echocardiographic predictors of improvement or worsening of mitral regurgitation in patients undergoing TAVR with moderate-to-severe mitral regurgitation.

METHODS

This retrospective study included 113 patients who underwent TAVR with preoperative mitral regurgitation grade at least 2. Patients with concomitant coronary artery disease requiring treatment were excluded. Mitral regurgitation was related to the annular dilatation or tethering mechanism in all patients. Preoperative and postoperative echocardiographies were compared in terms of mitral regurgitation and other commonly measured parameters.

RESULTS

After TAVR, a reduction in mitral regurgitation was observed in 62.8% of cases. On the basis of the difference between postoperative and preoperative echocardiograms, 71 patients had improved mitral regurgitation, whereas 42 patients had stable or worsened mitral regurgitation. After analyzing preoperative echocardiographic parameters with regard to this group difference, left atrial volume index (LAVI) was the only variable that was different between groups (33.4 ± 4.8 ml/m in improved mitral regurgitation vs. 39.8 ± 3.0 ml/m in not improved mitral regurgitation, P < 0.001). In a multivariable logistic regression model, a LAVI increase was associated with lack of an acute reduction in mitral regurgitation (odds ratio = 1.41, P < 0.001) after adjustment for age and preoperative serum creatinine.

CONCLUSION

Higher preoperative LAVI is a determinant predictor of lack of an acute reduction in mitral regurgitation after TAVR, and LAVI could be used as a stratifying tool to tailor the treatment strategy and the timing of the procedures. However, validation of these results and long-term outcomes are warranted to support those conclusions.