Mitral Valve Regurgitation in the Contemporary Era

The various perioperative issues of structural heart diseases and cardiogenic shock

Up to 20 % of patients presenting with acute heart failure and cardiogenic shock have a structural etiology. Despite efforts in timely management, mortality rates remain alarmingly high, ranging from 50 % to 80 %. Surgical intervention is often the definitive treatment for structural heart disease; however, many patients are considered high risk or unsuitable candidates for such procedures. Consequently, there has been a paradigm shift towards the development of novel percutaneous management strategies and temporizing interventions. This article aims to provide a comprehensive review of the pathophysiology of valvular and structural heart conditions presenting in cardiogenic shock, focusing on the evolving landscape of mechanical circulatory support devices and other management modalities.

Acute Heart Valve Emergencies

Within the cardiac intensive care unit, prompt recognition of severe acute valvular lesions is essential because hemodynamic collapse can occur rapidly, especially when cardiac chambers have not had time for compensatory remodeling. Within this context, optimal medical management, considerations for temporary mechanical circulatory support and decisive treatments strategies are addressed. Fundamental concepts include an appreciation for how sudden changes in flow and pressure gradients between cardiac chambers can impact hemodynamic and echocardiographic findings differently compared to similarly severe chronic lesions, as well as understanding the main causes for decompensated heart failure and cardiogenic shock for each valvular abnormality.

Mitral Transcatheter Edge-to-Edge Repair: Advancing Treatment Options for Degenerative Mitral Regurgitation

Degenerative mitral regurgitation (DMR) has earned great interest because of modern and innovative technologies emerging in its treatment. MR affects roughly one-tenth of those older adults over the age of 75. MR if untreated leads to adverse heart remodeling, resulting in left ventricular dysfunction, pulmonary hypertension, and heart failure syndrome. Despite surgical valve repair/replacement treatment being the standard of care, a significant proportion of severe MR patients face unmet clinical needs because of high or prohibitive surgical risks. This has led to the emergence of transcatheter therapies for high- and prohibitive-risk surgical patients, most notably mitral transcatheter edge-to-edge repair devices.

Proof of Concept: Development of a Mitral Annuloplasty Ring With Crosshatch Net

OBJECTIVE

Here we report our preclinical, proof-of-concept testing to assess the ability of a novel device to correct mitral regurgitation. The Milwaukee Heart device aims to enable any cardiac surgeon to perform high-quality mitral valve repair using a standard annuloplasty ring with a crosshatch of microporous, monofilament suture.

METHODS

Hemodynamic, echocardiographic, and videographic data were collected at baseline, following induction of mitral regurgitation, and after repair using porcine hearts in an ex vivo biosimulator model. A commercially available cardiac prosthesis assessment platform was then used to assess the hydrodynamic characteristics of the study device.

RESULTS

Porcine biosimulator pressure and flow metrics exhibited successful correction of mitral regurgitation following device implantation with similar values to baseline. Hydrodynamic results yielded pressure gradients and an effective orifice area comparable to currently approved prostheses.

CONCLUSIONS

The study device effectively reduced mitral valve regurgitation and improved hemodynamics in our preclinical model with similar biophysical metrics to currently approved devices. Future in vivo trials are needed to evaluate the efficacy, biocompatibility, and freedom from the most likely adverse events, such as device thrombosis, embolic events, and hemolysis.

Mitral transcatheter edge-to-edge repair: patient selection, current devices, and clinical outcomes

INTRODUCTION

Over the last two decades, mitral transcatheter edge-to-edge repair (M-TEER) has become a safe and effective therapy for severe mitral regurgitation in patients deemed at high surgical risk.

AREAS COVERED

This review aims to encompass the most relevant and updated evidence in the field of M-TEER from its inception, focusing on clinical and anatomical features for proper patient and device selection.

EXPERT OPINION

Growing operator experience and device iterations have resulted in improved clinical outcomes and an expansion of the therapy to patients with complex anatomies and clinical scenarios. Future investigations are warranted to determine the best management options and the most suitable device for every patient with MR.

Expert proposal to analyze the combination of aortic and mitral regurgitation in multiple valvular heart disease by comprehensive echocardiography

The assessment of valvular pathologies in multiple valvular heart disease by echocardiography remains challenging. Data on echocardiographic assessment-especially in patients with combined aortic and mitral regurgitation-are rare in the literature. The proposed integrative approach using semi-quantitative parameters to grade the severity of regurgitation often yields inconsistent findings and results in misinterpretation. Therefore, this proposal aims to focus on a practical systematic echocardiographic analysis to understand the pathophysiology and hemodynamics in patients with combined aortic and mitral regurgitation. The quantitative approach of grading the regurgitant severity of each compound might be helpful in elucidating the scenario in combined aortic and mitral regurgitation. To this end, both the individual regurgitant fraction of each valve and the total regurgitant fraction of both valves must be determined. This work also outlines the methodological issues and limitations of the quantitative approach by echocardiography. Finally, we present a proposal that enables verifiable assessment of regurgitant fractions. The overall interpretation of echocardiographic results includes the symptomatology of patients with combined aortic and mitral regurgitation and the individual treatment options with respect to their individual risk. In summary, a reproducible, verifiable, and transparent in-depth echocardiographic investigation might ensure consistent hemodynamic plausibility of the quantitative results in patients with combined aortic and 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.

Safety and efficacy of the DragonFly system for transcatheter valve repair of degenerative mitral regurgitation: one-year results of the DRAGONFLY-DMR trial

BACKGROUND

Severe degenerative mitral regurgitation (DMR) can cause a poor prognosis if left untreated. For patients considered at prohibitive surgical risk, transcatheter edge-to-edge repair (TEER) has become an accepted alternative therapy. The DragonFly transcatheter valve repair system is an innovative evolution of the mitral TEER device family to treat DMR.

AIMS

Herein we report on the DRAGONFLY-DMR trial (ClinicalTrials.gov: NCT04734756), which was a prospective, single-arm, multicentre study on the safety and effectiveness of the DragonFly system.

METHODS

A total of 120 eligible patients with prohibitive surgical risk and DMR ≥3+ were screened by a central eligibility committee for enrolment. The study utilised an independent echocardiography core laboratory and clinical event committee. The primary endpoint was the clinical success rate, which measured freedom from all-cause mortality, mitral valve reintervention, and mitral regurgitation (MR) >2+ at 1-year follow-up.

RESULTS

At 1 year, the trial successfully achieved its prespecified primary efficacy endpoint, with a clinical success rate of 87.5% (95% confidence interval: 80.1-92.3%). The rates of major adverse events, all-cause mortality, mitral valve reintervention, and heart failure hospitalisation were 9.0%, 5.0%, 0.8%, and 3.4%, respectively. MR ≤2+ was 90.4% at 1 month and 92.0% at 1 year. Over time, left ventricular reverse remodelling was observed (p<0.05), along with significant improvements in the patients' functional and quality-of-life outcomes, shown by an increase in the New York Heart Association Class I/II from 32.4% at baseline to 93.6% at 12 months (p<0.001) and increased Kansas City Cardiomyopathy Questionnaire (KCCQ) score of 31.1±18.2 from baseline to 12 months (p<0.001).

CONCLUSIONS

The DRAGONFLY-DMR trial contributes to increasing evidence supporting the safety and efficacy of TEER therapy, specifically the DragonFly system, for treating patients with chronic symptomatic DMR 3+ to 4+ at prohibitive surgical risk.

Respect Versus Resect Approaches for Mitral Valve Repair: A Meta-Analysis of Reconstructed Time-to-Event Data

Mitral valve repair (MVr) has been associated with superior long-term survival and freedom from valve-related complications compared with mitral valve replacement for primary mitral regurgitation (MR). The 2 main approaches for MVr are chordal replacement ("respect approach") and leaflet resection ("resect approach"). We performed a systematic review and a meta-analysis using 3 search databases to compare the long-term end points between both approaches. The primary end point was long-term survival. The secondary end points were long-term MR recurrence and reoperation. After reconstruction of time-to-event data for the individual survival analysis, pooled Kaplan-Meier curves for the end points were generated. A total of 14 studies (5,565 patients) were included in the analysis. The respect approach was associated with superior survival compared with the resect approach in the overall sample (hazard ratio [HR] 0.73, 95% confidence interval [CI] 0.56 to 0.96, p = 0.024, n = 3,901 patients) but not in the risk-adjusted sample (HR 1.00, 95% CI 0.55 to 1.82, p = 0.991, n = 620 patients). There was no difference between the approaches in the rate of MR recurrence in the overall sample (HR 1.39, 95% CI 0.92 to 2.08, p = 0.116, n = 1,882 patients) or in the risk-adjusted sample (HR 1.62, 95% CI 0.76 to 3.47, p = 0.211, n = 288 patients). The data for reoperation were only available in the overall sample and did not reveal a difference (HR 0.92, 95% CI 0.62 to 1.35, p = 0.663, n = 3,505 patients). In conclusion, the current evidence suggests no difference in long-term mortality, MR recurrence, or reoperation between the resect and respect approaches for MVr after adjusting for patient risk factors. More long-term follow-up data are warranted.

Unique Aspects of Women's Valvular Heart Diseases: Impact for Diagnosis and Treatment

Valvular heart diseases (VHDs) are a major cause of cardiovascular morbidity and mortality worldwide. As degenerative and functional mechanisms represent the main etiologies in high-income countries are degenerative and functional, while in low income countries etiologie is mostly rheumatic. Although therapeutic options have evolved considerably in recent years, women are consistently diagnosed at later stages of their disease, are delayed in receiving surgical referrals, and exhibit worse postoperative outcomes, compared to men. This difference is a result of the historical underrepresentation of women in studies from which current guidelines were developed. However, in recent years, important research, including more female patients, has been conducted and has highlighted substantial sex-specific differences in the etiology, diagnosis, and treatment of VHDs. Systematic consideration of these sex-specific differences in VHD patients is crucial for providing equitable healthcare and optimizing clinical outcomes in both female and male patients. Hence, this review aims to explore implications of sex-specific particularities for diagnosis, treatment options, and outcomes in women with VHDs.

Echocardiographic quantification of mitral apparatus morphology and dynamics in patients with dilated cardiomyopathy

Mitral regurgitation is among the most common valvular heart diseases. Mitral regurgitation in patients with dilated cardiomyopathy is a complex pathology involving annular dilatation, papillary muscle displacement, systolic leaflet tethering, and left ventricular remodeling. Quantification of mitral apparatus damage in these patients is essential for successful interventional and surgical therapy. Mitral regurgitation in the presence of dilated cardiomyopathy is classified as Carpentier type IIIB, with restricted leaflet mobility as a standard feature. Echocardiography allows accurate evaluation of the complex anatomy and function of the mitral apparatus. Updated guidelines recommend two-dimensional followed by systematic three-dimensional echocardiographic evaluation in patients with mitral regurgitation. New three-dimensional echocardiographic software packages provide many parameters that help identify the precise morphology and function of the various components of the mitral apparatus, helping to determine the etiology of mitral regurgitation and evaluate disease severity. This review provides the first point-by-point approach to the assessment of all old and new echocardiographic methods, from the simplest to the most complex, used to examine the components of the mitral valve apparatus in patients with dilated cardiomyopathy. Although these parameters are still under research, this information will be helpful for establishing therapeutic procedures in a disease with a poor prognosis.

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.

Interventional management of mitral regurgitation and sleep disordered breathing: "Catching two birds with one stone"

Sleep disordered breathing (SDB), mostly constituting of obstructive and central sleep apnea (OSA and CSA, respectively), is highly prevalent in the general population, and even more among patients with cardiovascular disease, heart failure (HF) and valvular heart disease, such as mitral regurgitation (MR). The coexistence of HF, MR and SDB is associated with worse cardiovascular outcomes and increased morbidity and mortality. Pulmonary congestion, as a result of MR, can exaggerate and worsen the clinical status and symptoms of SDB, while OSA and CSA, through various mechanisms that impair left ventricular dynamics, can promote left ventricular remodelling, mitral annulus dilatation and consequently MR. Regarding treatment, positive airway pressure devices used to ameliorate symptoms in SDB also seem to result in a reduction of MR severity, MR jet fraction and an improvement of left ventricular ejection fraction. However, surgical and transcatheter interventions for MR, and especially transcatheter edge to edge mitral valve repair (TEER), seem to also have a positive effect on SDB, by reducing OSA and CSA-related severity indexes and improving symptom control. The purpose of this review is to provide a comprehensive analysis of the common pathophysiology between SDB and MR, as well as to discuss the available evidence regarding the effect of SDB treatment on MR and the effect of mitral valve surgery or transcatheter repair on both OSA and CSA.

Timing of Surgery for Asymptomatic Primary Mitral Regurgitation: Possible Value of Early, Serial Measurements of Left Ventricular Sphericity

Asymptomatic primary mitral regurgitation due to myxomatous degeneration of the mitral valve leaflets may remain so for long periods, even as left ventricular function progresses to a decompensated stage. During the early compensated stage, the ventricle's initial response to the volume overload is an asymmetric increase in the diastolic short axis dimension, accomplished by a diastolic shift of the interventricular septum into the right ventricular cavity, creating a more spherical left ventricular diastolic shape, increasing diastolic filling and stroke volume. Early valve repair is recommended to reduce postoperative left ventricular dysfunction. Early serial measurements of left ventricular sphericity index [LV-Si]. during the compensated stage of mitral regurgitation might identify subtle changes in left ventricular shape and assist in determining the optimal earliest timing for surgical intervention.

Valvular heart disease and cardiomyopathy: reappraisal of their interplay

Cardiomyopathies and valvular heart diseases are typically considered distinct diagnostic categories with dedicated guidelines for their management. However, the interplay between these conditions is increasingly being recognized and they frequently coexist, as in the paradigmatic examples of dilated cardiomyopathy and hypertrophic cardiomyopathy, which are often complicated by the occurrence of mitral regurgitation. Moreover, cardiomyopathies and valvular heart diseases can have a shared aetiology because several genetic or acquired diseases can affect both the cardiac valves and the myocardium. In addition, the association between cardiomyopathies and valvular heart diseases has important prognostic and therapeutic implications. Therefore, a better understanding of their shared pathophysiological mechanisms, as well as of the prevalence and predisposing factors to their association, might lead to a different approach in the risk stratification and management of these diseases. In this Review, we discuss the different scenarios in which valvular heart diseases and cardiomyopathies coexist, highlighting the need for an improved classification and clustering of these diseases with potential repercussions in the clinical management and, particularly, personalized therapeutic approaches.

The Results of Urgent and Emergent Transcatheter Mitral Valve Repair (MitraClip®): A Comparison with Standard Elective Repair

Background

Mitral regurgitation (MR) is the most common valvular disease worldwide. MR has been managed surgically, with either a mitral valve replacement or repair. Percutaneous transcatheter mitral valve repair (TMVr) with MitraClip® insertion has gained wide popularity and success over medical and surgical therapy for MR. Some patients with acute MR or decompensated heart failure could benefit from urgent TMVr. This meta-analysis aims to compare clinical outcomes of urgent versus elective TMVr.

Methods

We performed a study-level meta-analysis to compare the clinical outcomes of urgent versus elective TMVr using the MitraClip system. The primary endpoint outcome was all-cause mortality. Additional outcomes included procedural success, postoperative acute kidney injury (AKI), stroke, and length of in-hospital stay.

Results

Overall, 30-day mortality was significantly higher in the urgent group (odds ratio [OR]: 2.74; 95% confidence interval [CI] [2.17, 3.48]; P < 0.00001; I² =0%). However, subgroup analysis of matched cohorts showed no significant difference between both groups (OR: 1.80; 95% CI [0.94, 3.46]; P = 0.08; I² =0%). One-year mortality was similar between both groups (and: 1.67; 95% CI [0.96, 2.90]; P = 0.07; I² =0%). Procedural success was similar between both groups (89.4% vs. 89.8%; P = 0.43). Postoperative AKI was significantly higher in the urgent group (OR: 4.12; 95% CI [2.87, 5.91]; P < 0.00001; I² =0%).

Conclusion

Urgent TMVr should be indicated in select populations as it is considered therapeutic with acceptable outcomes therein.

Cardiac Amyloidosis and Valvular Heart Disease

Growing interest has accrued in the co-existence of cardiac amyloidosis and valvular heart disease. Amyloid infiltration from either transthyretin (ATTR) or of light chain (AL) origin may affect any structure of the heart, including the valves. The recent literature has mainly focused on aortic stenosis and cardiac amyloidosis, improving our understanding of the epidemiology, diagnosis, treatment and prognosis of this dual pathology. Despite being of high clinical relevance, data on mitral/tricuspid regurgitation and cardiac amyloidosis are rather scarce and mostly limited to case reports and small cases series. It is the aim of this review article to summarize the current evidence of concomitant valvular heart disease and cardiac amyloidosis by including studies on epidemiology, diagnostic approaches, screening possibilities, therapeutic management, and prognostic implications.

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.

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.

Long-term echocardiographic data, mechanisms of failure, and reintervention outcomes of the Epic valve in mitral position-a large observational cohort

OBJECTIVES

Long-term echocardiographic reports on mitral valve (MV) porcine xenograft bioprosthesis (Epic) are lacking, and postreintervention outcomes of failed Epic are unknown. We aimed to assess the mechanisms and independent predictors of Epic failures and to compare short- and mid-term outcomes according to reintervention type.

METHODS

We included consecutive patients (n = 1397; mean age: 72 ± 8 years; 46% female; mean follow-up: 4.8 years) who received the Epic during mitral valve replacement (MVR) at our institution. Clinical, echocardiographic, reintervention, and outcomes data were retrieved from our prospective institution's database or government statistics.

RESULTS

Gradients and effective orifice area of the Epic were stable over 5-years follow-up. A total of 70 (5%) patients had a MV reintervention at median follow-up of 3.0 (0.7-5.4) years due to prosthesis failure, by redo-MVR (n = 38; 54%), valve-in-valve (n = 19; 27%), paravalvular leak (PVL) closure (n = 12; 17%), or thrombectomy (n = 1). Mechanisms of failure were 27 (1.9%) structural valve deterioration (SVD; all leaflet tear); 16 (1.1%) non-SVD (15 PVL, 1 pannus); 24 (1.7%) endocarditis; and 4 (0.3%) thrombosis. Freedom from all-cause and SVD-related MV reintervention at 10 years are 88% and 92%, respectively. Independent predictors of reintervention were age, baseline atrial fibrillation, initial MV etiology, and moderate or greater PVL at discharge (all P ≤ .05). Comparison of redo-MVR and valve-in-valve revealed no significant difference in early outcomes or mid-term mortality (all P ≥ .16).

CONCLUSIONS

The Epic Mitral valve has stable hemodynamics through 5 years and is associated with low incidence of SVD and reintervention, mostly due to endocarditis and leaflet tear without calcification. Reintervention type had no influence on early outcomes and mid-term mortality.

Integrating Echocardiography Parameters With Explainable Artificial Intelligence for Data-Driven Clustering of Primary Mitral Regurgitation Phenotypes

BACKGROUND

Primary mitral regurgitation (MR) is a heterogeneous clinical disease requiring integration of echocardiographic parameters using guideline-driven recommendations to identify severe disease.

OBJECTIVES

The purpose of this preliminary study was to explore novel data-driven approaches to delineate phenotypes of MR severity that benefit from surgery.

METHODS

The authors used unsupervised and supervised machine learning and explainable artificial intelligence (AI) to integrate 24 echocardiographic parameters in 400 primary MR subjects from France (n = 243; development cohort) and Canada (n = 157; validation cohort) followed up during a median time of 3.2 years (IQR: 1.3-5.3 years) and 6.8 (IQR: 4.0-8.5 years), respectively. The authors compared the phenogroups' incremental prognostic value over conventional MR profiles and for the primary endpoint of all-cause mortality incorporating time-to-mitral valve repair/replacement surgery as a covariate for survival analysis (time-dependent exposure).

RESULTS

High-severity (HS) phenogroups from the French cohort (HS: n = 117; low-severity [LS]: n = 126) and the Canadian cohort (HS: n = 87; LS: n = 70) showed improved event-free survival in surgical HS subjects over nonsurgical subjects (P = 0.047 and P = 0.020, respectively). A similar benefit of surgery was not seen in the LS phenogroup in both cohorts (P = 0.70 and P = 0.50, respectively). Phenogrouping showed incremental prognostic value in conventionally severe or moderate-severe MR subjects (Harrell C statistic improvement; P = 0.480; and categorical net reclassification improvement; P = 0.002). Explainable AI specified how each echocardiographic parameter contributed to phenogroup distribution.

CONCLUSIONS

Novel data-driven phenogrouping and explainable AI aided in improved integration of echocardiographic data to identify patients with primary MR and improved event-free survival after mitral valve repair/replacement surgery.

Renal Outcomes Following Transcatheter Mitral Valve Repair - Analysis of COAPT Trial Data

The prevalence of valvular heart disease in the United States has been estimated at 4.2-to-5.6 million, with mitral regurgitation (MR) being the most common lesion. Significant MR is associated with heart failure (HF) and death if left untreated. When HF is present, renal dysfunction (RD) is common and is associated with worse outcomes (ie, it is a marker of HF disease progression). Additionally, a complex interplay exists in patients with HF who also have MR, as this combination further impairs renal function, and the presence of RD further worsens prognosis and often limits guideline-directed management and therapy (GDMT). This has important implications in secondary MR because GDMT is the standard of care. However, with the development of minimally invasive transcatheter mitral valve repair, mitral transcatheter edge-to-edge repair (TEER) has become a new treatment option for secondary MR that is now incorporated into current guidelines published in 2020 that listed mitral TEER as a class 2a recommendation (moderate recommendation with benefit >> risk) as an addition to GDMT in a subset of patients with left ventricular ejection fraction <50%. The Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation (COAPT) trial, which demonstrated favorable outcomes in secondary MR by adding mitral TEER to GDMT versus GDMT alone, was the evidence base for these guidelines. Considering these guidelines and the understanding that concomitant RD often limits GDMT in secondary MR, there is emerging research studying the renal outcomes from the COAPT trial. This review analyzes this evidence, which could further influence current decision-making and future guidelines.

Effect of Telehealth Services on Mitral and Tricuspid Regurgitation Progression: Retrospective Study

BACKGROUND

Mitral regurgitation (MR) and tricuspid regurgitation (TR) are common cardiac conditions with high mortality risks, which can be improved through early intervention. Telehealth services, which allow for remote monitoring of patient conditions, have been proven to improve the health management of chronic diseases, but the effects on MR and TR progression are unknown.

OBJECTIVE

This study aimed to explore whether patients receiving telehealth services have less MR and TR progression compared with a control group. We also aimed to identify the determinants of MR and TR progression.

METHODS

This single-center retrospective study conducted at the National Taiwan University Hospital compared MR and TR progression (defined as either progression to moderate or greater MR and TR or MR and TR progression by ≥2 grades during the study period) between the telehealth and control groups. Patients had a minimum of 2 transthoracic echocardiograms at least 6 months apart; baseline mild-moderate MR and TR or lower; and no prior surgeries on the mitral or tricuspid valve. Telehealth patients were defined as those who received telehealth services for at least 28 days within 3 months of baseline. Basic demographics, baseline blood pressure measurements, prescribed medication, and Charlson Comorbidity Index components were obtained for all patients.

RESULTS

A total of 1081 patients (n=226 in the telehealth group and n=855 in the control group) were included in the study analyses. The telehealth group showed significantly lower baseline systolic blood pressure (P<.001), higher Charlson Comorbidity Index (P=.02), higher prevalence of prior myocardial infarction (P=.01) and heart failure (P<.001), higher beta-blocker (P=.03) and diuretic (P=.04) use, and lower nitrate use (P=.04). Both groups showed similar cardiac remodeling conditions at baseline. Telehealth was found to be neutral for both MR (hazard ratio 1.10, 95% CI 0.80-1.52; P=.52) and TR (hazard ratio 1.27, 95% CI 0.92-1.74; P=.14) progression. Determinants for moderate or greater MR progression included older age, female sex, diuretic use, larger left atrial dimension, left ventricular end-diastolic dimension, left ventricular end-systolic dimension, and lower left ventricular ejection fraction. Determinants of moderate or greater TR progression included older age, female sex, diuretic use, presence of atrial fibrillation, LA dimension, left ventricular end-systolic dimension, and lower left ventricular ejection fraction; statin use was found to be protective.

CONCLUSIONS

This is the first study to assess the association between telehealth services and the progression of MR and TR. Telehealth patients, who had more comorbidities, displayed similar MR and TR progression versus control patients, indicating that telehealth may slow MR and TR progression. Determinants of MR and TR progression included easy-to-measure traditional echo parameters of cardiac function, older age, female sex, and atrial fibrillation, which can be incorporated into a telehealth platform and advanced alert system, improving patient outcomes through personalized care.

Pimobendan prevents cardiac dysfunction, mitigates cardiac mitochondrial dysfunction, and preserves myocyte ultrastructure in a rat model of mitral regurgitation

BACKGROUND

Pimobendan has been proven to delay the onset of congestive heart failure (CHF) in dogs with mitral regurgitation (MR); however, molecular underlying mechanisms have not been fully elucidated. This study aimed to investigate (1) the effects of pimobendan on cardiac function, cardiac mitochondrial quality and morphology, and cardiac ultrastructure in a rat model of chronic MR and (2) the direct effect of pimobendan on intracellular reactive oxygen species (ROS) production in cardiac cells. MR was surgically induced in 20 Sprague-Dawley rats, and sham procedures were performed on 10 rats. Eight weeks post-surgery, the MR rats were randomly divided into two groups: the MR group and the MR + pimobendan group. Pimobendan (0.15 mg/kg) was administered twice a day via oral gavage for 4 weeks, whereas the sham and MR groups received equivalent volumes of drinking water. Echocardiography was performed at baseline (8 weeks post-surgery) and at the end of the study (4 weeks after treatment). At the end of the study protocol, all rats were euthanized, and their hearts were immediately collected, weighed, and used for transmission electron microscopy and mitochondrial quality assessments. To evaluate the role of pimobendan on intracellular ROS production, preventive or scavenging properties were tested with H2O2-induced ROS generation in rat cardiac myoblasts (H9c2).

RESULTS

Pimobendan preserved cardiac functions and structure in MR rats. In addition, pimobendan significantly improved mitochondrial quality by attenuating ROS production and depolarization (P < 0.05). The cardiac ultrastructure and mitochondrial morphology were significantly preserved in the MR + pimobendan group. In addition, pimobendan appeared to play as a ROS scavenger, but not as a ROS preventer, in H2O2-induced ROS production in H9c2 cells.

CONCLUSIONS

Pimobendan demonstrated cardioprotective effects on cardiac function and ultrastructure by preserving mitochondrial quality and acted as an ROS scavenger in a rat model of MR.

Data-driven mortality risk prediction of severe degenerative mitral regurgitation patients undergoing mitral valve surgery

AIMS

The outcomes of mitral valve replacement/repair (MVR) in severe degenerative mitral regurgitation (MR) patients depend on various risk factors. We aimed to develop a risk prediction model for post-MVR mortality in severe degenerative MR patients using machine learning.

METHODS AND RESULTS

Consecutive severe degenerative MR patients undergoing MVR were analysed (n = 1521; 70% training/30% test sets). A random survival forest (RSF) model was constructed, with 3-year post-MVR all-cause mortality as the outcome. Partial dependency plots were used to define the thresholds of each risk factor. A simple scoring system (MVR-score) was developed to stratify post-MVR mortality risk. At 3 years following MVR, 90 patients (5.9%) died in the entire cohort (59 and 31 deaths in the training and test sets). The most important predictors of mortality in order of importance were age, haemoglobin, valve replacement, glomerular filtration rate, left atrial dimension, and left ventricular (LV) end-systolic diameter. The final RSF model with these six variables demonstrated high predictive performance in the test set (3-year C-index 0.880, 95% confidence interval 0.834-0.925), with mortality risk increased strongly with left atrial dimension >55 mm, and LV end-systolic diameter >45 mm. MVR-score demonstrated effective risk stratification and had significantly higher predictability compared to the modified Mitral Regurgitation International Database score (3-year C-index 0.803 vs. 0.750, P = 0.034).

CONCLUSION

A data-driven machine learning model provided accurate post-MVR mortality prediction in severe degenerative MR patients. The outcome following MVR in severe degenerative MR patients is governed by both clinical and echocardiographic factors.

Prognostic Significance of Flail Mitral Leaflet in Transcatheter Edge-to-Edge Repair for Primary Mitral Regurgitation

Despite the growing experience with MitraClip in the broad spectrum of mitral regurgitation (MR), limited data are available regarding the independent prognostic role on survival of different mitral regurgitation etiology subtypes. We sought to evaluate the impact of flail leaflet etiology in a large series of patients with primary MR (PMR) who underwent MitraClip treatment. The study included 588 patients with significant PMR from the multicenter GIOTTO (Italian Society of Interventional Cardiology [GIse] registry Of Transcatheter treatment of mitral valve regurgitaTiOn), stratified into 2 groups according to MR etiology: flail+ (n = 300) and flail- (n = 288). The primary end point was a composite of cardiac death and first rehospitalization for heart failure (HF). To account for the baseline differences, patients were propensity score-matched 1:1. Flail leaflet etiology was present in about a half of the patients. Acute technical success was achieved in 98% of the overall cohort, with no significant differences between the study groups (p = 0.789). At the 2-year Kaplan-Meier analysis, the primary end point occurred in 13% of flail+ patients compared with 23% in flail- (p = 0.009). The flail+ group presented lower rates of both cardiac death and rehospitalization for HF, whereas a similar overall death rate was observed between the groups. A multivariate Cox regression analysis identified flail leaflet etiology as an independent predictor of favorable outcome in terms of the primary end point (hazard ratio 0.141, 95% confidence interval 0.049 to 0.401, p <0.001). After propensity score matching, flail+ patients had confirmed lower rates of cardiac mortality and rehospitalization for HF but similar rates of overall death. In conclusion, flail leaflet-related etiology was common in patients with PMR who underwent MitraClip treatment and was an independent predictor of midterm favorable clinical outcomes.

Vericiguat preserved cardiac function and mitochondrial quality in a rat model of mitral regurgitation

AIMS

New drugs for heart failure (HF) that target restoring the impaired NO-sGC-cGMP pathway are being developed. We aimed to investigate the effects of vericiguat, an sGC stimulator, on cardiac function, blood pressure (BP), cardiac mitochondrial quality, and cardiac fibrosis in rat models of chronic mitral regurgitation (MR).

MATERIALS AND METHODS

We surgically induced MR in 20 Sprague-Dawley rats and performed sham procedures on 10 rats (negative control). Four weeks post-surgery, we randomly divided the MR rats into two groups: MR group and MR + vericiguat group. Vericiguat (0.5 mg/kg, PO) was administered once a day via oral gavage for 8 weeks, while the sham and MR groups received equivalent volumes of drinking water instead. We took echocardiography and BP measurements at baseline (4 weeks post-surgery) and at the end of study (8 weeks after treatment). At the study end, all rats were euthanized and their hearts were immediately collected, weighed, and used for histopathology and mitochondrial quality assessments.

KEY FINDINGS

Vericiguat preserved cardiac functions and structural remodeling in the MR rats, with significantly lower systolic BPs than baseline values (P < 0.05). Additionally, vericiguat significantly improved the mitochondrial quality by attenuating ROS production, depolarization and swelling when comparing the values in both groups (P < 0.05). The fibrosis area also significantly decreased in the MR + vericiguat group (P < 0.05).

SIGNIFICANCE

Vericiguat demonstrated cardioprotective effects on cardiac function, BP, and fibrosis by preserving mitochondrial quality in rats with HF due to MR.

Contemporary Review of Transcatheter Mitral Valve Interventions for Mitral Regurgitation

Mitral regurgitation (MR) is the most common form of valvular heart disease in the United States, and there are established guidelines for indications for requiring mitral valve surgeries. However, there is an unmet clinical need for a subset of high-risk MR patients, especially those with advanced age, heart failure and/or secondary MR. Following the successes of transcatheter aortic valve replacements, significant advances have occurred over the last decade in transcatheter mitral valve interventions in order to manage these patients in both clinical practice and trials. The three main types of these interventions include a transcatheter edge-to-edge repair, percutaneous mitral annuloplasty (both direct and indirect) and transcatheter mitral valve replacement (including when applied to a prior prosthetic valve, annuloplasty ring and mitral annuloplasty ring). This review aims to discuss the contemporary techniques, evidence, indications, multimodality imaging evaluations and outcomes of the various transcatheter mitral valve interventions.

Primary Mitral Regurgitation and Heart Failure: Current Advances in Diagnosis and Management

Primary mitral regurgitation is a frequent etiology of congestive heart failure and is best treated with intervention when patients are symptomatic or when additional risk factors exist. Surgical intervention improves outcomes in appropriately selected patients. However, for those at high surgical risk, transcatheter intervention provides less invasive repair and replacement options while providing comparable outcomes to surgery. The excess mortality and high prevalence of heart failure in untreated mitral regurgitation illuminate the need for further developments in mitral valve intervention ideally fulfilled by expanding these types of procedures and eligibility to these procedures beyond only those at high surgical risk.

Mitral valve geometrical echocardiographic analysis and 3D computational modeling of a normal mitral valve

Aim: This research aims to develop a consistent computational model of a normal mitral valve (MV) and describe mitral regurgitation (MR) geometry based on Carpentier's classification. Materials & methods: MV geometry was assessed by 2D transthoracic echocardiogram in 100 individuals. A 3D parametric geometric model of the MV was developed. A computational model of a normal MV was performed. Results: The simulation of the valve function was successfully accomplished and its kinematics was analyzed. Differences in geometry were revealed between normal and type III MR. Conclusion: 3D computational models of the normal MV can be constructed relying on standard measurements performed by 2D echocardiography. Certain geometrical differences exist among the normal and the most severe type of MR.

Valvular heart disease in Japan: Characteristics and treatment of patients in acute care hospitals in 2019

BACKGROUND

Valvular heart disease (VHD) is one of the commonest causes of cardiovascular morbidity and mortality worldwide, with acquired VHD especially prevalent in countries with aging populations. The scope and pattern of disease are not well understood, as some patients are asymptomatic and available options for invasive treatment vary by affected valve. We sought to understand the burden of VHD in Japan including the distribution of patients by valve disease type and age, using administrative claims data from acute care hospitals.

METHODS

This was a retrospective descriptive study of patients with VHD diagnosis and at least one record of echocardiography in 2019 documented in the Medical Data Vision database. Affected valve(s) and type of valve disease were characterized using ICD-10 codes; patients undergoing invasive treatment for VHD at the same facility and during the same year as their diagnosis were assessed using procedure codes.

RESULTS

Of 203,398 patients with VHD diagnosis and a record of echocardiography in 2019, 49.0 % had a mitral valve disorder, 44.9 % aortic valve, 22.9 % tricuspid valve, and 2.2 % pulmonic valve (14.9 % of patients had more than one disordered valve). A total of 7201 patients (<4 % of the total diagnosed population) received invasive treatment for VHD in 2019 at the diagnosing hospital. Patients with aortic stenosis (AS) had the highest mean age, at 79 years. Although mitral regurgitation was the most common VHD among diagnosed patients, AS predominated in the cohort of treated patients. A substantial portion of patients undergoing treatment for AS were age 85 years or older (27.2 %).

CONCLUSIONS

The cohort of treated patients in 2019 was a small fraction of the total population with a VHD diagnosis in that year. Wide availability of transcatheter treatment for AS in Japan may be allowing more elderly patients to receive intervention than in other types of VHD.

Acute and Chronic Changes in Myocardial Work Parameters in Patients with Severe Primary Mitral Regurgitation Undergoing Transcatheter Edge-to-Edge Repair

Background: The noninvasive assessment of myocardial work (MW) allows for the evaluation of left ventricular (LV) performance by considering the effect of LV afterload. This study aims to evaluate the acute and chronic impact of transcatheter edge-to-edge repair (TEER) on MW parameters and LV remodeling in patients with severe primary mitral regurgitation (PMR). Methods: A total of 71 patients (age: 77 ± 9 years, females: 44%) with moderate–to-severe or severe PMR (effective regurgitant orifice: 0.57 ± 0.31 cm2; regurgitant volume: 80 ± 34 mL; LV end-systolic diameter: 42 ± 12 mm) underwent TEER after a global assessment by the heart team. MW indices were evaluated before the procedure, at hospital discharge, and at 1-year follow-up. LV remodeling was described as the percentage variation in LVEDV between baseline and 1-year follow-up. Results: TEER caused an acute reduction in LVEF, global longitudinal strain (GLS), global MW index (GWI), work efficiency (GWE), and mechanical dispersion (MD) and a significant increase in wasted work (GWW). One year after the procedure, GLS, GWI, GWE, and MD recovered, whereas GWW remained significantly impaired. Baseline GWW (β = −0.29, p = 0.03) was an independent predictor of LV reverse remodeling at 1-year follow-up. Conclusions: In patients with severe PMR undergoing TEER, the acute reduction in LV preload causes significant impairment to all the parameters of LV performance. Baseline GWW was the only independent predictor of LV reverse remodeling, suggesting that a lower myocardial energetic efficiency in the context of chronic preload increase might impact the left ventricular response to mitral regurgitation correction.

Longitudinal Outcomes Following Surgical Repair of Primary Mitral Regurgitation

Degenerative mitral valve (MV) disease is the most common cause of organic mitral regurgitation (MR) in developed countries. Surgical mitral valve repair is the gold standard treatment for primary MR. Surgical mitral valve repair is associated with excellent outcomes in terms of survival and freedom from recurrent MR. As well, innovations in surgical repair techniques, including thoracoscopically and robotically assisted approaches, further reduce morbidity. Emerging catheter-based therapies may also provide advantages in select patient groups. Although the outcomes following surgical mitral valve repair are well described in the literature, longitudinal follow-up is heterogenous. Indeed, longitudinal follow-up and long-term data are vital to better advise treatment and counsel patients.

Prediction of Surgical Approach in Mitral Valve Disease by XGBoost Algorithm Based on Echocardiographic Features

In this study, we aimed to develop a prediction model to assist surgeons in choosing an appropriate surgical approach for mitral valve disease patients. We retrospectively analyzed a total of 143 patients who underwent surgery for mitral valve disease. The XGBoost algorithm was used to establish a predictive model to decide a surgical approach (mitral valve repair or replacement) based on the echocardiographic features of the mitral valve apparatus, such as leaflets, the annulus, and sub-valvular structures. The results showed that the accuracy of the predictive model was 81.09% in predicting the appropriate surgical approach based on the patient's preoperative echocardiography. The result of the predictive model was superior to the traditional complexity score (81.09% vs. 75%). Additionally, the predictive model showed that the three main factors affecting the choice of surgical approach were leaflet restriction, calcification of the leaflet, and perforation or cleft of the leaflet. We developed a novel predictive model using the XGBoost algorithm based on echocardiographic features to assist surgeons in choosing an appropriate surgical approach for patients with mitral valve disease.

Society of thoracic surgeons risk score and left atrial pressure for predicting clinical outcomes among transcatheter mitral edge-to-edge repair patients

BACKGROUND

Limited data exist regarding the performance of the Society of Thoracic Surgeons (STS) risk score among transcatheter mitral edge-to-edge repair (TEER) patients.

OBJECTIVE

Evaluate STS score accuracy, and the incremental value of post-procedural left atrial pressure (LAP).

METHODS

A retrospective analysis of TEER patients between 2013 and 2020. Patients were allocated into 3 groups: high (≥8% [n = 298, 31%]), intermediate (4%-8% [n = 318, 33%]), and low (<4% [n = 344, 36%]). Primary outcomes included 1-year mortality or cardiovascular hospitalizations. Cox proportional hazards regression modeling was used to determine the hazard ratio of the primary outcome, and STS score accuracy was assessed by receiver operating characteristic. A spline curve was used to display the relationship between LAP and the primary endpoint. Continuous net reclassification improvement (NRI) was used to determine the incremental value of LAP.

RESULTS

We included 960 patients, primarily elderly (79 [70-85]), with a median STS risk of 5.6 (3-9). High-risk patients were older (83 [75-89], 81 [74-87], 72 [64-79], p < 0.001), and had more comorbidities compared to intermediate and low-risk groups. Upon Cox regression, STS score (high vs. low: HR 2.5 [1.7-3.8]; Intermediate vs. low: HR 1.8 [1.2-2.7] and LAP HR 1.03 [1.01-1.06], p = 0.007) were associated with the outcome. C statistics analysis revealed low accuracy of the STS score (AUC-0.61 [0.58-0.65, p < 0.001]). Continuous NRI analysis indicated an improvement in risk prediction of 17% (6.9-26.2), p < 0.001.

CONCLUSION

STS risk score has low accuracy in predicting clinical outcomes after TEER. Adding LAP measurements can improve reclassification and identify those prone to adverse outcomes.

Long-term outcomes in distinct phenogroups of patients with primary mitral regurgitation undergoing valve surgery

OBJECTIVES

Patients with mitral regurgitation (MR) may be heterogeneous with different risk profiles. We aimed to identify distinct phenogroups of patients with severe primary MR and investigate their long-term prognosis after mitral valve (MV) surgery.

METHODS

The retrospective cohort of patients with severe primary MR undergoing MV surgery (derivation, n=1629; validation, n=692) was analysed. Latent class analysis was used to classify patients into subgroups using 15 variables. The primary outcome was all-cause mortality after MV surgery.

RESULTS

During follow-up (median 6.0 years), 149 patients (9.1%) died in the derivation cohort. In the univariable Cox analysis, age, female, atrial fibrillation, left ventricular (LV) end-systolic dimension/volumes, LV ejection fraction, left atrial dimension and tricuspid regurgitation peak velocity were significant predictors of mortality following MV surgery. Five distinct phenogroups were identified, three younger groups (group 1-3) and two older groups (group 4-5): group 1, least comorbidities; group 2, men with LV enlargement; group 3, predominantly women with rheumatic MR; group 4, low-risk older patients; and group 5, high-risk older patients. Cumulative survival was the lowest in group 5, followed by groups 3 and 4 (5-year survival for groups 1-5: 98.5%, 96.0%, 91.7%, 95.6% and 83.4%; p<0.001). Phenogroups had similar predictive performance compared with the Mitral Regurgitation International Database score in patients with degenerative MR (3-year C-index, 0.763 vs 0.750, p=0.602). These findings were reproduced in the validation cohort.

CONCLUSION

Five phenogroups of patients with severe primary MR with different risk profiles and outcomes were identified. This phenogrouping strategy may improve risk stratification when optimising the timing and type of interventions for severe MR.

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.

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.

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.

Mitral and tricuspid valve disease: diagnosis and management. Consensus document of the Section on Valvular Heart Disease and the Cardiovascular Imaging, Clinical Cardiology, and Interventional Cardiology Associations of the Spanish Society of Cardiology

The diagnosis and management of mitral and tricuspid valve disease have undergone major changes in the last few years. The expansion of transcatheter interventions and widespread use of new imaging techniques have altered the recommendations for the diagnosis and treatment of these diseases. Because of the exponential growth in the number of publications and clinical trials in this field, there is a strong need for continuous updating of local protocols. The recently published 2021 European Society of Cardiology guidelines for the management of valvular heart disease did not include some of the new data on these new therapies and, moreover, the number of mitral and tricuspid interventions varies widely across Europe. Therefore, all this information must be summarized to facilitate its use in each specific country. Consequently, we present the consensus document of the Section on Valvular Disease, Cardiovascular Imaging, Clinical Cardiology, and Interventional Cardiology Associations of the Spanish Society of Cardiology for the diagnosis and management of mitral and tricuspid valve disease.

Giant Coronary Sinus Complicated by Spontaneous Thrombosis

Spontaneous coronary sinus thrombosis (CST) is an extremely rare occurrence. Most cases are iatrogenic and related to right heart instrumentation, due to either central line placement or electrophysiology procedures such as pacemaker insertion that causes direct damage to the endothelial lining. The course can be insidious and may result in a fatal outcome. Diagnosis of CST is challenging, and the syndrome often goes unrecognized. However, in the current era of multimodality imaging, it is possible that this condition will be recognized in more patients. Herein, we present a patient with spontaneous coronary sinus thrombosis that was diagnosed using multimodality imaging and thereafter successfully managed.

Do Not Withhold Mitral Surgery from Patients with Poor Left Ventricular Function

Background and Objectives: Increasing reluctance to perform surgical mitral valve repair or replacement particularly in high-risk patients with poor left-ventricular function is trending. These patients are increasingly treated interventionally, e.g., by MitraClip, but often show only low to moderate improvement. The primary objective of the study was to investigate whether left ventricular ejection fraction (LVEF) influences postoperative mortality. Materials and Methods: The study included 903 patients undergoing mitral valve repair or replacement between 2009 and 2021. Statistical comparison was performed between patients with LVEF ≤ 30% and LVEF > 30%. Finally, statistical analysis was performed according to propensity score matching (1:3 PS matching). Results: No significant difference in in-hospital mortality was found before and after matching regarding LVEF ≤ 30% and LVEF > 30% (Pre: 10.8% vs. 15.1%, p = 0.241, after: 11.6% vs. 18.1%, p = 0.142). After PS matching, the 112 patients with LVEF ≤ 30% compared with 336 patients with LVEF > 30% showed a significantly higher preoperative NT-proBNP (p < 0.001), larger diameters at preoperative left ventricle and atrium (p < 0.001), lower preoperative TAPSE (p = 0.003) and PAP (p = 0.003), and more dilated cardiomyopathy and chronic kidney disease (p < 0.001, p = 0.045). Conclusions: The results of this study demonstrate that poor preoperative LVEF alone does not play a significant role in postoperative outcome and long-term mortality. Prognosis appears to be multifactorial. Poor preoperative LVEF is not a contraindication for surgery and does not justify primary interventional treatment accepting inferior hemodynamic results impeding outcome.

Percutaneous Atrio-Ventricular Valve Interventions: Contemporary Advances and Remaining Challenges

These are exciting exploratory times for structural/valvular heart interventions [...]

Late plasma exosome microRNA-21-5p depicts magnitude of reverse ventricular remodeling after early surgical repair of primary mitral valve regurgitation

Introduction

Primary mitral valve regurgitation (MR) results from degeneration of mitral valve apparatus. Mechanisms leading to incomplete postoperative left ventricular (LV) reverse remodeling (Rev-Rem) despite timely and successful surgical mitral valve repair (MVR) remain unknown. Plasma exosomes (pEXOs) are smallest nanovesicles exerting early postoperative cardioprotection. We hypothesized that late plasma exosomal microRNAs (miRs) contribute to Rev-Rem during the late postoperative period.

Methods

Primary MR patients (n = 19; age, 45-71 years) underwent cardiac magnetic resonance imaging and blood sampling before (T0) and 6 months after (T1) MVR. The postoperative LV Rev-Rem was assessed in terms of a decrease in LV end-diastolic volume and patients were stratified into high (HiR-REM) and low (LoR-REM) LV Rev-Rem subgroups. Isolated pEXOs were quantified by nanoparticle tracking analysis. Exosomal microRNA (miR)-1, -21-5p, -133a, and -208a levels were measured by RT-qPCR. Anti-hypertrophic effects of pEXOs were tested in HL-1 cardiomyocytes cultured with angiotensin II (AngII, 1 μM for 48 h).

Results

Surgery zeroed out volume regurgitation in all patients. Although preoperative pEXOs were similar in both groups, pEXO levels increased after MVR in HiR-REM patients (+0.75-fold, p = 0.016), who showed lower cardiac mass index (-11%, p = 0.032). Postoperative exosomal miR-21-5p values of HiR-REM patients were higher than other groups (p < 0.05). In vitro, T1-pEXOs isolated from LoR-REM patients boosted the AngII-induced cardiomyocyte hypertrophy, but not postoperative exosomes of HiR-REM. This adaptive effect was counteracted by miR-21-5p inhibition.

Summary/Conclusion

High levels of miR-21-5p-enriched pEXOs during the late postoperative period depict higher LV Rev-Rem after MVR. miR-21-5p-enriched pEXOs may be helpful to predict and to treat incomplete LV Rev-Rem after successful early surgical MVR.

The Prognostic Role of Mitral Valve Regurgitation Severity and Left Ventricle Function in Acute Heart Failure

Aims: Data about the prognostic interplay between mitral regurgitation MR and left ventricular (LV) function in the outcome of patients admitted with acute heart failure (AHF) are scarce. We evaluated the prognostic impact of MR severity and LV function on mortality and on recurrent heart failure hospitalization (re-HFH) in patients admitted with AHF. Methods and Results: In total, 6843 patients admitted with AHF were evaluated: 2521 patients with LV ejection fraction (LVEF) ≤ 40% (reduced LVEF), 1238 of them (51%) having ≥moderate MR; and 4322 with LVEF > 40% (preserved LVEF), 1175 of them (27%) having ≥moderate MR. One-year mortality and re-HFH rates were higher in patients with ≥moderate MR unrelated to the baseline LV function (p = 0.028 and p < 0.001, respectively). After multivariable analysis, only reduced LVEF, and not the severity of MR, predicted mortality risk (HR: 1.31 [95% CI: 1.12−1.53] for patients with reduced LV function and ≤mild MR; HR: 1.44 [95% CI: 1.25−1.67] for patients with reduced LV function and ≥moderate MR); p < 0.001 for both. There was an increased risk for re-HFH in each group (HR: 1.35 [95% CI: 1.17−1.52] for patients with preserved LV function and ≥moderate MR; HR: 1.31 [95% CI: 1.15−1.51] for patients with reduced LV function and mild MR; and HR: 1.65 [95% CI: 1.45−1.88] for patients with reduced LV function and ≥moderate MR); p < 0.001 for all. Conclusions: In patients admitted with AHF, the LV function is the main prognostic determinant for mortality after 1 year. Significant (≥moderate) MR is associated with an increased risk of recurrent hospitalization.

Practical Echocardiographic Approach of the Regurgitant Mitral Valve Assessment

Mitral regurgitation is the second-most frequent valvular heart disease in Europe after degenerative aortic stenosis. It is associated with significant morbidity and mortality, and its prevalence is expected to increase with population aging. Echocardiography is the first diagnostic approach to assess its severity, constituting a challenging process in which a multimodality evaluation, integrating quantitative, semiquantitative and qualitative methods, as well as a detailed evaluation of the morphology and function of both left ventricle and atria is the key. In this review, we would like to provide a practical diagnosis approach on the mitral valve regurgitation mechanism, severity quantification, and planning of future therapeutic options.

Treatment of secondary mitral regurgitation by transcatheter edge-to-edge repair using MitraClip

Transcatheter edge-to-edge repair (TEER) is becoming the standard invasive treatment for ventricular functional mitral regurgitation (MR). It is necessary to determine the severity of MR before treatment with MitraClip; however, the severity of secondary MR is usually underestimated compared with that of primary MR and varies temporally. Therefore, to accurately determine the severity of MR, it is important to correctly use the algorithm of the guidelines for valvular heart disease and aggressively perform stress echocardiography. Before performing TEER, the difficulty of the procedure should be evaluated. First, morphological features that make TEER unsuitable, such as cleft of the mitral leaflet, mitral stenosis (MS), or perforation of the mitral leaflet, should be checked. The mitral valve orifice area, transmitral valve pressure gradient, coaptation depth, coaptation length, and posterior leaflet length should be measured to determine the difficulty of the procedure based on the inclusion criteria of Endovascular Valve Edge-to-Edge Repair Study II and the German consensus. After MitraClip implantation, in addition to assessing the severity of MS and residual MR, the pulmonary venous flow pattern and stroke volume should be evaluated to comprehensively assess whether TEER improves the hemodynamics. MitraClip has also been used to treat atrial functional MR, another type of secondary MR. Several reports suggest that MitraClip is effective for atrial functional MR; however, evidence is still being accumulated.