Impact of cardiac resynchronization therapy on the severity of mitral regurgitation

Outcomes of mitral TEER in non-responders to cardiac resynchronization therapy: A systematic review and meta-analysis

BACKGROUND

Secondary mitral regurgitation (MR) worsens in 10-15 % of heart failure (HF) patients receiving cardiac resynchronization therapy (CRT). Transcatheter edge-to-edge repair (TEER) with Mitra-Clip (Abbot Vascular, Santa Clara, CA, USA) therapy is associated with improved survival and decreased rates of hospitalization for HF in selected patients with secondary MR. Data on TEER outcomes in CRT-non-responders are limited. The purpose of this meta-analysis was to evaluate outcomes of mitral TEER with Mitra-Clip in CRT-non-responders.

METHODS

Cochrane, Scopus, MEDLINE, and EMBASE were searched for studies discussing outcomes of Mitra-Clip in CRT non-responders. Two reviewers were independently involved in screening studies and extracting relevant data. Individual study incidence rate estimates underwent logit transformation to calculate the weighted summary proportion under the random effect model.

RESULTS

A total of eight reports met the inclusion criteria (439 patients). Mitra-Clip improved MR grade to ≤2+ in 83.8 % and 86.8 % of CRT non-responders at six months and one year, respectively. Symptomatic improvement (New York Heart Association class ≤II) was also found in 71 % and 78.1 % of CRT non-responders at six months and one year, respectively. The pooled overall incidence estimates of mortality at 30 days, 6 months, 1 year, and 2 years were 3.6 %, 9.2 %, 17.8 %, and 25.9 %, respectively.

CONCLUSION

TEER with Mitra-Clip in patients with significant secondary MR who do not respond to CRT was associated with MR improvement, alleviation of symptoms, and mortality rates similar to those in the COAPT trial.

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

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

Impact of transcatheter edge to edge repair in functional mitral regurgitation and cardiac resynchronization-therapy nonresponders

BACKGROUND

Despite optimal medical therapy and cardiac resynchronization therapy (CRT), significant functional mitral regurgitation (MR) persisted in 30% of the patients and labeled as CRT nonresponders.

AIMS

We sought to study the impact of transcatheter edge-to-edge repair (TEER) in patients with symptomatic grade III and IV functional MR despite CRT.

METHODS

A retrospective analysis was conducted of all patients who had prior CRT for at least 6 months and underwent TEER for significant residual functional MR (grade ≥3) and symptomatic heart failure (HF) at our institution. The primary outcomes were the change in New York Heart Association classification (NYHA), MR grade, echo parameters, and NT-ProBNP from baseline to 1-year post-procedure.

RESULTS

A total of 28 patients were identified, mean age of 73 ± 6.7 years and 89% males. Procedure success was achieved in all patients. At 1-year follow-up, patients had lower MR grade (median 2, IQR 1 [1,2] vs. 4, IQR 1 [3,4]; p < 0.001), NYHA class (median 2, IQR 1 [2,3] vs. 3, IQR 1 [3,4]; p < 0.001), and NT-ProBNP (7658 ± 11322 vs. 3760 ± 4431; p = 0.035) compared to before the TEER procedure. The left ventricular end-diastolic volume (255 ± 59 vs. 244 ± 66 mm; p = 0.016) and the right ventricular systolic pressure (52 ± 14 mmHg vs. 37 ± 13 mmHg, <0.001) decreased.

CONCLUSION

Patients who remain symptomatic after CRT with severe functional MR had improved functional status and MR grade at 1-year following TEER. There was a signal toward reverse remodeling.

Predictors of functional mitral regurgitation improvement in patients with left bundle branch block treated with left bundle branch area pacing

BACKGROUND

Functional mitral regurgitation (FMR) and its severity are associated with adverse outcomes in heart failure patients. This study aims to analyze the predictors of FMR improvement after successful left bundle branch area pacing (LBBAP) in patients with LVEF < 50% and complete left bundle branch block (CLBBB).

METHODS

Consecutive patients with LVEF < 50% and CLBBB who underwent successful LBBAP from July 2018 to July 2023 were retrospectively identified. Significant MR was defined as regurgitation of moderate severity or greater. Patients with significant FMR were included in the analysis. FMR improvement (FMRI) was defined as a reduction of at least one grade in regurgitation severity compared to baseline at 3 months or longer follow-up.

RESULTS

Among the 81 identified patients, 42 patients with significant FMR preoperatively were included. After LBBAP, QRS duration significantly shortened from 170.6 ± 18.8 ms to 114.5 ± 20.2 ms (p < .001). Significant FMR improves in approximately 76.2%, and the patients were divided into an FMRI group (n = 32) and a non-FMRI group (n = 10). Univariate analysis showed that absence of persistent atrial fibrillation, typical CLBBB, and left atrium diameter at baseline were associated with improvement of FMR after LBBAP. Of these variables, only absence of persistent atrial fibrillation remains an independent predictor in the multivariate model (OR 12.436, p = .009).

CONCLUSION

LBBAP is able to improve FMR in heart failure patients who had CLBBB with LVEF < 50%. Meanwhile, the absence of persistent atrial fibrillation is an independent predictor of FMR improvement.

Evolution and prognosis of tricuspid and mitral regurgitation following cardiac implantable electronic devices: a systematic review and meta-analysis

AIMS

Significant changes in tricuspid regurgitation (TR) and mitral regurgitation (MR) post-cardiac implantable electronic devices (CIEDs) are increasingly recognized. However, uncertainty remains as to whether the risk of CIED-associated TR and MR differs with right ventricular pacing (RVP) via CIED with trans-tricuspid RV leads, compared with cardiac resynchronization therapy (CRT), conduction system pacing (CSP), and leadless pacing (LP). The study aims to synthesize extant data on risk and prognosis of significant post-CIED TR and MR across pacing strategies.

METHODS AND RESULTS

We searched PubMed, EMBASE, and Cochrane Library databases published until 31 October 2023. Significant post-CIED TR and MR were defined as ≥ moderate. Fifty-seven TR studies (n = 13 723 patients) and 90 MR studies (n = 14 387 patients) were included. For all CIED, the risk of post-CIED TR increased [pooled odds ratio (OR) = 2.46 and 95% CI = 1.88-3.22], while the risk of post-CIED MR reduced (OR = 0.74, 95% CI = 0.58-0.94) after 12 and 6 months of median follow-up, respectively. Right ventricular pacing via CIED with trans-tricuspid RV leads was associated with increased risk of post-CIED TR (OR = 4.54, 95% CI = 3.14-6.57) and post-CIED MR (OR = 2.24, 95% CI = 1.18-4.26). Binarily, CSP did not alter TR risk (OR = 0.37, 95% CI = 0.13-1.02), but significantly reduced MR (OR = 0.15, 95% CI = 0.03-0.62). Cardiac resynchronization therapy did not significantly change TR risk (OR = 1.09, 95% CI = 0.55-2.17), but significantly reduced MR with prevalence pre-CRT of 43%, decreasing post-CRT to 22% (OR = 0.49, 95% CI = 0.40-0.61). There was no significant association of LP with post-CIED TR (OR = 1.15, 95% CI = 0.83-1.59) or MR (OR = 1.31, 95% CI = 0.72-2.39). Cardiac implantable electronic device-associated TR was independently predictive of all-cause mortality [pooled hazard ratio (HR) = 1.64, 95% CI = 1.40-1.90] after median of 53 months. Mitral regurgitation persisting post-CRT independently predicted all-cause mortality (HR = 2.00, 95% CI = 1.57-2.55) after 38 months.

CONCLUSION

Our findings suggest that, when possible, adoption of pacing strategies that avoid isolated trans-tricuspid RV leads may be beneficial in preventing incident or deteriorating atrioventricular valvular regurgitation and might reduce mortality.

Valvular heart disease: from mechanisms to management

Valvular heart disease is common and its prevalence is rapidly increasing worldwide. Effective medical therapies are insufficient and treatment was historically limited to the surgical techniques of valve repair or replacement, resulting in systematic underprovision of care to older patients and those with substantial comorbidities, frailty, or left ventricular dysfunction. Advances in imaging and surgical techniques over the past 20 years have transformed the management of valvular heart disease. Better understanding of the mechanisms and causes of disease and an increasingly extensive and robust evidence base provide a platform for the delivery of individualised treatment by multidisciplinary heart teams working within networks of diagnostic facilities and specialist heart valve centres. In this Series paper, we aim to provide an overview of the current and future management of valvular heart disease and propose treatment approaches based on an understanding of the underlying pathophysiology and the application of multidisciplinary treatment strategies to individual patients.

Heart Failure and Secondary Mitral Regurgitation: A Contemporary Review

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

Mitral Interventions in Heart Failure

Patients with heart failure with reduced ejection fraction who have secondary mitral regurgitation (SMR) have poorer outcomes and quality of life than those without SMR. Guideline-directed medical therapy is the cornerstone of SMR treatment. Careful evaluation of landmark trials using mitral transcatheter edge-to-edge repair in SMR has led to an improved understanding of who will benefit from percutaneous interventions with emphasis on a multidisciplinary approach. The success with mitral transcatheter edge-to-edge repair in SMR has also spurred the evaluation of its role in populations that were not initially studied, such as end-stage heart failure and cardiogenic shock. A spectrum of transcatheter devices in development and clinical trials promise to further provide a growing array of management options for heart failure with reduced ejection fraction patients with symptomatic SMR.

Medical Therapy for Functional Mitral Regurgitation

Functional mitral regurgitation (FMR) can be broadly categorized into 2 main groups: ventricular and atrial, which often coexist. The former is secondary to left ventricular remodeling usually in the setting of heart failure with reduced ejection fraction or less frequently due to ischemic papillary muscle remodeling. Atrial FMR develops due to atrial and annular dilatation related to atrial fibrillation/flutter or from increased atrial pressures in the setting of heart failure with preserved ejection fraction. Guideline-directed medical therapy is the first step and prevails as the mainstay in the treatment of FMR. In this review, we address the medical therapeutic options for FMR management and highlight a targeted approach for each FMR category. We further address important clinical and echocardiographic characteristics to aid in determining when medical therapy is expected to have a low yield and an appropriate window for effective interventional approaches exists.

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.

Percutaneous Edge-to-Edge Mitral Valve Repair for Functional Mitral Regurgitation

The presence and severity of functional mitral regurgitation (FMR) is associated with worse outcomes in patients with heart failure and reduced ejection fraction. Prior to the availability of percutaneous mitral valve repair, management for FMR has been limited to medical therapy, cardiac resynchronization therapy for a specific subset of patients and surgery which has yet to demonstrate mortality benefits. Transcatheter edge-to-edge repair (TEER) of the mitral valve has emerged in the past decade as an invaluable member of the armamentarium against FMR with the 2 landmark randomized controlled trials providing deep insights on patient selection. In addition, TEER has spurred the rapid advancement in our understanding of FMR. This article seeks to provide an overview as well as our current understanding on the role of TEER in FMR.

Predictors of persistence of functional mitral regurgitation after cardiac resynchronization therapy: Review of literature

Functional mitral regurgitation is a common finding among heart failure patients with ischemic and non-ischemic dilated cardiomyopathies. The presence of moderate or severe mitral regurgitation is associated with higher morbidity and mortality. Heart failure patients meeting electrocardiogram and left ventricle function criteria are good candidates for cardiac resynchronization therapy, which may reduce the degree of functional mitral regurgitation in the short and long term, specifically targeting myocardial dyssynchrony and inducing left ventricle reverse remodeling. In this article, we analyze data from the literature about predictors of mitral regurgitation improvement after cardiac resynchronization therapy implantation.

The role of three dimensional transesophageal echocardiography in predicting the effect of cardiac resynchronization therapy on mitral regurgitation in patients with low ejection fraction heart failure

PURPOSE

Cardiac resynchronization therapy (CRT) positively affects the improvement of functional mitral regurgitation (MR) in patients with heart failure with reduced ejection fraction (HFrEF). However, geometric changes in the mitral valve apparatus, subvalvular structures and their contribution to improving mitral regurgitation after CRT have not been clearly defined. Our study aimed to evaluate the geometric parameters of mitral valve apparatus measured with three-dimensional (3D) transesophageal echocardiography (TEE) before CRT implantation and to determine the parameters predicting the improvement of MR after CRT.

METHODS

In this prospective study, we included thirty patients with moderate or severe MR and HFrEF planned for CRT implantation who had an indication for TEE. Before CRT implantation, effective regurgitant orifice (ERO) and regurgitant volume (RV) measurements were performed. Detailed quantitative measurements of the mitral valve were done from recorded images by 3D TEE. ERO and RV measurements were repeated to evaluate MR at the end of the third month.

RESULTS

There were no significant changes in left ventricular EF and left ventricular diameters at third-month follow-up, whereas ERO and RV values were decreased. The posterior leaflet angle was higher in the non-responder group than the responder group (28.93 ± 8.41 vs 41.25 ± 10.90, p = 0.006). The posterior leaflet angle was an independent predictor of decreased RV and ERO.

CONCLUSION

Among HFrEF patients with moderate or severe functional MR who underwent CRT implantation had a lower posterior leaflet angle, which was measured by 3D TEE, in the patient group whose MR improved after CRT.

Epidemiology, Pathophysiology, and Management of Native Atrioventricular Valve Regurgitation in Heart Failure Patients

Atrioventricular regurgitation is frequent in the setting of heart failure. It is due to atrial and ventricular remodelling, as well as rhythmic disturbances and loss of synchrony. Once atrioventricular regurgitation develops, it can aggravate the underlying heart failure, and further participate and aggravate its own severity. Its presence is therefore concomitantly a surrogate of advance disease and a predictor of mortality. Heart failure management, including medical therapy, cardiac resynchronization therapy, and restoration of sinus rhythm, are the initial steps to reduce atrioventricular regurgitation. In the current review, we analyse the current data assessing the epidemiology, pathophysiology, and impact of non-valvular intervention on atrioventricular regurgitation including medical treatment, cardiac resynchronization and atrial fibrillation ablation.

Suppression of acute heart failure rehospitalization by biventricular pacing in wide QRS and mid-range ejection fraction

We present a 66-year-old male patient with heart failure, mid-range ejection fraction and QRS widening suffering from recurrent hospitalization due to acute heart failure. We measured intra-cardiac pressure by cardiac catheterization to clearly demonstrate the augmentation of afterload by a vasoconstricting drug induced increase of left ventricular end-diastolic blood pressure and pulmonary capillary wedge pressure with pulmonary arterial V-wave augmentation (indicator of worsening of mitral regurgitation). Because the patient was considered as refractory to optimal medication, cardiac resynchronization therapy (CRT) was performed. After CRT implantation, these factors were improved, and the patient has not experienced recurrent hospitalization for >2 years.

Ischemic Mitral Regurgitation: A Multifaceted Syndrome with Evolving Therapies

Dysfunction of the left ventricle (LV) with impaired contractility following chronic ischemia or acute myocardial infarction (AMI) is the main cause of ischemic mitral regurgitation (IMR), leading to moderate and moderate-to-severe mitral regurgitation (MR). The site of AMI exerts a specific influence determining different patterns of adverse LV remodeling. In general, inferior-posterior AMI is more frequently associated with regional structural changes than the anterolateral one, which is associated with global adverse LV remodeling, ultimately leading to different phenotypes of IMR. In this narrative review, starting from the aforementioned categorization, we proceed to describe current knowledge regarding surgical approaches in the management of IMR.

Effect of Carillon Mitral Contour System on patient-reported outcomes in functional mitral regurgitation: an individual participant data meta-analysis

Aims

The Carillon Mitral Contour System has been shown to reduce mitral regurgitation and left ventricular volumes in symptomatic heart failure patients with functional mitral regurgitation. We sought to evaluate the effects of the Carillon device on quality of life and functional capacity in these patients.

Methods and results

An individual participant data meta‐analysis was conducted utilizing data from REDUCE‐FMR, TITAN, and TITAN II studies. The main outcomes assessed were changes from baseline in Kansas City Cardiomyopathy Questionnaire overall summary scores (KCCQ‐OSS), 6 min walk test (6MWT) distance, and New York Heart Association (NYHA) classification at Months 1 and 12 after device implantation. Subgroup analyses were conducted for patients with severe functional mitral regurgitation (Grade 3 or 4). Pooled estimates were calculated using a random‐effects model and are presented as weighted proportions or weighted mean differences along with 95% confidence intervals (CIs). Among 139 patients included in the analysis, Carillon device significantly improved the 6MWT distance (63.0 m; 95% CI 18.8–107.2, P = 0.0056) and KCCQ‐OSS score (15.1; 95% CI 5.6–24.7, P = 0.0022) at 1 month from baseline. These benefits were sustained at 12 months (64.1 m; 95% CI 13.2–115.0, P = 0.0141, for 6MWT distance, and 12.3; 95% CI 4.7–19.8, P = 0.0019, for KCCQ‐OSS score). More than 50% of the patients had improvements in KCCQ‐OSS by ≥5 (60.4%; 95% CI 47.4–72.1) and 10 points (50.5%; 95% CI 34.9–66.0) at 12 months. Almost half of the patients experienced a ≥1 class improvement in NYHA class after implantation of the device at 1 month (67.9%; 95% CI 37.3–88.3) and at 12 months (48.8%; 95% CI 31.8–66.2). Results remained similar for KCCQ‐OSS, 6MWT distance, and NYHA classification when only patients with Grade 3 or 4 mitral regurgitation were analysed. The pooled estimates of 30 day and 1 year all‐cause mortality were 2.2% (95% CI 0.7–6.5) and 17.3% (95% CI 11.8–24.5), respectively.

Conclusions

The Carillon Mitral Contour System significantly improved patient‐reported quality‐of‐life outcomes in heart failure patients with functional mitral regurgitation.

The role of transcatheter mitral valve leaflet approximation for the treatment of secondary mitral regurgitation: current status and future prospects

Introduction: Secondary mitral regurgitation (SMR) is one of the most common valvulopathies and is associated with poor prognosis. Over the past years, medical management and mitral valve repair options have rapidly evolved offering new opportunities for a wide range of patients.Areas covered: We provide an up-to-date review of the value of medical and transcatheter mitral valve leaflet approximation for SMR integrating the results of most recent trials and putting their findings into clinical perspective.Expert opinion: Treatment of SMR requires a multidisciplinary approach with a long-term perspective. After optimization of medical treatment, transcatheter mitral valve repair should be considered in patients with persisting symptomatic severe SMR to improve symptoms and prognosis.

The management of secondary mitral regurgitation in patients with heart failure: a joint position statement from the Heart Failure Association (HFA), European Association of Cardiovascular Imaging (EACVI), European Heart Rhythm Association (EHRA), and European Association of Percutaneous Cardiovascular Interventions (EAPCI) of the ESC

Secondary (or functional) mitral regurgitation (SMR) occurs frequently in chronic heart failure (HF) with reduced left ventricular (LV) ejection fraction, resulting from LV remodelling that prevents coaptation of the valve leaflets. Secondary mitral regurgitation contributes to progression of the symptoms and signs of HF and confers worse prognosis. The management of HF patients with SMR is complex and requires timely referral to a multidisciplinary Heart Team. Optimization of pharmacological and device therapy according to guideline recommendations is crucial. Further management requires careful clinical and imaging assessment, addressing the anatomical and functional features of the mitral valve and left ventricle, overall HF status, and relevant comorbidities. Evidence concerning surgical correction of SMR is sparse and it is doubtful whether this approach improves prognosis. Transcatheter repair has emerged as a promising alternative, but the conflicting results of current randomized trials require careful interpretation. This collaborative position statement, developed by four key associations of the European Society of Cardiology-the Heart Failure Association (HFA), European Association of Percutaneous Cardiovascular Interventions (EAPCI), European Association of Cardiovascular Imaging (EACVI), and European Heart Rhythm Association (EHRA)-presents an updated practical approach to the evaluation and management of patients with HF and SMR based upon a Heart Team approach.

Percutaneous Mitral Valve Intervention Using MitraClip for Functional Mitral Regurgitation and Heart Failure

Functional mitral regurgitation (FMR) frequently coexists with left ventricular systolic dysfunction and advanced heart failure, and typically has poor clinical outcomes. Although various therapeutic options including cardiac resynchronization therapy and surgical mitral intervention, have been proposed, an optimal treatment strategy for functional mitral regurgitation has not yet been established. Over the last decade, transcatheter mitral valve repair using MitraClip has emerged as a novel alternative therapeutic option for functional mitral regurgitation. In 2018, the COAPT trial demonstrated that MitraClip treatment reduced rehospitalization due to heart failure and all-cause death in patients with functional mitral regurgitation and heart failure. As a consequence, the MitraClip has become a very promising potential treatment for functional mitral regurgitation. In this review, we discuss and summarize the current status and future perspectives of the treatment for functional mitral regurgitation and heart failure.

The mechanism and prognosis of acute and late improvement in mitral regurgitation after cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) improves functional mitral regurgitation (MR); however, the mechanism and differences in acute and late improvement in MR are unclear. We aimed to evaluate the factors associated with the acute and late MR improvements and the prognosis of MR improvement after CRT. This retrospective study included 121 patients who underwent CRT implantation with full echocardiography assessment at baseline, 1 week, and 6 months after implantation. MR severity was classified into five grades (0: none to 4: severe). Two-dimensional speckle-tracking echocardiography with radial strain was used to assess dyssynchrony, and the time difference between the lateral and inferior segments at papillary muscle levels (TD_late-inf) was calculated. The MR improved 1 week and 6 months after CRT in 40 (33%) and 45 (37%) patients, respectively. On multivariate analyses, TD_late-inf (baseline-1 week) and SPWMD were independently associated with acute MR improvement. The %reduction in left ventricular end-systolic volume (LVESV) (baseline-6 months) and TD_late-inf (baseline-1 week) were independently correlated with late MR improvement. The patients with pre-MR grades 2-4 and improved MR after CRT showed significantly better prognosis in heart failure hospitalization. Cutoff values of ≥ 19.5 ms of the reduction of TD_late-inf and ≥ 30.8% of the %reduction of LVESV were significantly associated with the decrease in heart failure hospitalization. The improved interpapillary muscle activation time delay and volume reduction after CRT were associated with acute and late MR improvements. There may be different time course of recovery and distinct causes for late MR improvement.

Transcatheter Mitral Valve Repair in Patients With and Without Cardiac Resynchronization Therapy: The COAPT Trial

BACKGROUND

In the COAPT trial (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation), treatment of heart failure (HF) patients with moderate-severe or severe secondary mitral regurgitation with transcatheter mitral valve repair (TMVr) using the MitraClip plus guideline-directed medical therapy (GDMT) reduced 2-year rates of HF hospitalization and all-cause mortality compared with GDMT alone. Whether the benefits of the MitraClip extend to patients with previously implanted cardiac resynchronization therapy (CRT) is unknown. We sought to examine the effect of prior CRT in patients enrolled in COAPT.

METHODS

Patients (N=614) with moderate-severe or severe secondary mitral regurgitation who remained symptomatic despite maximally tolerated doses of GDMT were randomized 1:1 to the MitraClip (TMVr arm) versus GDMT only (control arm). Outcomes were assessed according to prior CRT use.

RESULTS

Among 614 patients, 224 (36.5%) had prior CRT (115 and 109 randomized to TMVr and control, respectively) and 390 (63.5%) had no CRT (187 and 203 randomized to TMVr and control, respectively). Patients with CRT had similar 2-year rates of the composite of death or HF hospitalization compared with those without CRT (57.6% versus 55%, P=0.32). Death or HF hospitalization at 2 years was lower with TMVr versus control treatment in patients with prior CRT (48.6% versus 67.2%, hazard ratio, 0.60 [95% CI, 0.42-0.86]) and without CRT (42.5% versus 66.9%, hazard ratio, 0.52 [95% CI, 0.39-0.69]; adjusted P_interaction=0.23). The effects of TMVr with the MitraClip on reducing the 2-year rates of all-cause death (adjusted P_interaction=0.14) and HF hospitalization (adjusted P_interaction=0.82) were also consistent in patients with and without CRT as were improvements in quality-of-life and exercise capacity.

CONCLUSIONS

In the COAPT trial, TMVr with the MitraClip improved the 2-year prognosis of patients with HF and moderate-severe or severe secondary mitral regurgitation who remained symptomatic despite maximally tolerated GDMT, regardless of prior CRT implantation. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01626079.

Functional mitral regurgitation and cardiac resynchronization therapy in the "era" of trans-catheter interventions: Is it time to move from a staged strategy to a tailored therapy?

Cardiac resynchronization therapy (CRT) has been associated to left ventricle (LV) remodelling, reduction of functional mitral regurgitation (FMR) and clinical improvement in patients with heart failure and reduced ejection fraction (HFrEF). The prevalence of significant FMR in patients with LV dyssynchrony that are candidate to CRT is up to 40%. Current approach in patients with FMR undergoing CRT consists of re-evaluation of the amount of FMR following a waiting period of at least 3 months after the implant. In case of persistent significant FMR despite CRT and guideline directed medical therapy, trancatheter Mitral Valve repair (TMVR) is an important option to improve quality of life and prognosis. This stepwise approach does not take into account the probability of the individual response to CRT and the availability of TMVR solutions that are safe and effective in high risk patients. We reviewed the effects of CRT on FMR, the prognostic role of persistence of FMR after CRT treatment and the impact of treatment of FMR in patients CRT non responders. We aimed to point out the limits of current step-wised approach in light on more recent evidence regarding FMR treatment. A new, "tailored" approached is proposed.

Contrasting Effects of Pharmacological, Procedural, and Surgical Interventions on Proportionate and Disproportionate Functional Mitral Regurgitation in Chronic Heart Failure

Two distinct pathways can lead to functional mitral regurgitation (MR) in patients with chronic heart failure and a reduced ejection fraction. When remodeling and enlargement of the left ventricle (LV) cause annular dilatation and tethering of the mitral valve leaflets, there is a linear relationship between LV end-diastolic volume and the effective regurgitant orifice area of the mitral valve. These patients, designated as having proportionate MR, respond favorably to treatments that lead to reversal of LV remodeling and a decrease in LV volumes (eg, neurohormonal antagonists and LV assist devices), but they may not benefit from interventions that are directed only at the mitral valve leaflets (eg, transcatheter mitral valve repair). In contrast, when ventricular dyssynchrony causes functional MR attributable to unequal contraction of the papillary muscles, the magnitude of regurgitation is greater than that predicted by LV volumes. These patients, designated as having severe but disproportionate MR, respond favorably to treatments that are directed to the mitral valve leaflets or their supporting structures (eg, cardiac resynchronization or transcatheter mitral valve repair), but they may derive little benefit from interventions that act only to reduce LV cavity size (eg, pharmacological treatments). This novel conceptual framework reflects the important interplay between LV geometry and mitral valve function in determining the clinical presentation of patients, and it allows characterization of the determinants of functional MR to guide the most appropriate therapy in the clinical setting.

Ischemic Mitral Regurgitation: Current Understanding and Surgical Options

Secondary, or functional, mitral regurgitation (MR) occurs with impaired coaptation of structurally normal valve leaflets due to abnormal structure and/or function of the left ventricle (LV). A leading cause of functional mitral regurgitation is ischemic cardiomyopathy, resulting in left ventricular dysfunction and subsequent congestive heart failure (CHF) and ischemic mitral regurgitation (IMR). The value of surgical or transcatheter correction of IMR remains controversial, since the underlying pathology of IMR is attributed to a dysfunctional left ventricle. However, even mild IMR has been shown to be harmful to CHF patients, as IMR is both a surrogate of advanced CHF and an independent contributor to CHF morbidity and mortality. While observational and randomized studies have examined surgical treatment of IMR with conflicting outcomes, additional well-designed randomized controlled trials should be performed to further clarify the optimal treatment for IMR. Additionally, close attention should be paid to the quality of interventions performed, as durable reduction in IMR provides the best hope of a positive clinical outcome. This review focuses on the pathophysiology of IMR, current evidence regarding surgical and transcatheter interventions, and future directions in management of IMR.

Current role of echocardiography in cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is an established treatment for patients with heart failure and left ventricular systolic dysfunction. Patients are usually assessed by echocardiography, which provides a number of anatomical and functional information used for cardiac dyssynchrony assessment, prognostic stratification, identification of the optimal site of pacing in the left ventricle, optimization of the CRT device, and patient follow-up. Compared to other cardiac imaging techniques, echocardiography has the advantage to be non-invasive, repeatable, and safe, without exposure to ionizing radiation or nefrotoxic contrast. In this article, we review current evidence about the role of echocardiography before, during, and after the implantation of a CRT device.

Avoiding non-responders to cardiac resynchronization therapy: a practical guide

Over two decades after the introduction of cardiac resynchronization therapy (CRT) into clinical practice, ∼30% of candidates continue to fail to respond to this highly effective treatment of drug-refractory heart failure (HF). Since the causes of this non-response (NR) are multifactorial, it will require multidisciplinary efforts to overcome. Progress has, thus far, been slowed by several factors, ranging from a lack of consensus regarding the definition of NR and technological limitations to the delivery of therapy. We critically review the various endpoints that have been used in landmark clinical trials of CRT, and the variability in response rates that has been observed as a result of these different investigational designs, different sample populations enrolled and different means of therapy delivered, including new means of multisite and left ventricular endocardial simulation. Precise recommendations are offered regarding the optimal device programming, use of telemonitoring and optimization of management of HF. Potentially reversible causes of NR to CRT are reviewed, with emphasis on loss of biventricular stimulation due to competing arrhythmias. The prevention of NR to CRT is essential to improve the overall performance of this treatment and lower its risk-benefit ratio. These objectives require collaborative efforts by the HF team, the electrophysiologists and the cardiac imaging experts.

Effect of cardiac resynchronization therapy on mitral valve geometry: a novel aspect as "reversed mitral remodeling"

Amelioration of the valvular geometry is a possible mechanism for mitral regurgitation (MR) improvement in patients receiving cardiac resynchronization therapy (CRT). We aimed to establish the precise definition, incidence, and predictors of reversed mitral remodeling (RMR), as well as the association with MR improvement and short-term CRT outcome. Ninety-five CRT recipients were retrospectively evaluated for the end-point of "MR response" defined as the absolute reduction in regurgitant volume (RegV) at 6 months. To identify RMR, changes in mitral deformation indices were tested for correlation with MR response and further analyzed for functional and echocardiographic CRT outcomes. Overall, MR response was observed in 50 patients (53%). Among the echocardiographic indices, the change in tenting area (TA) had the highest correlation with the change in RegV (r = 0.653, p < 0.001). The mean TA significantly decreased in MR responders (4.15 ± 1.05 to 3.67 ± 1.01 cm² at 6 months, p < 0.001) and increased in non-responders (3.68 ± 1.04 to 3.98 ± 0.97 cm², p = 0.014). The absolute TA reduction was used to identify patients with RMR (47%) which was found to be associated with higher rates of functional improvement (p = 0.03) and volumetric CRT response (p = 0.036) compared to those without RMR. Non-ischemic etiology and the presence of LBBB independently predicted RMR at multivariate analysis. In conclusion, reduction in TA is a reliable index of RMR, which relates to MR response, and functional and echocardiographic improvement with CRT. LBBB and non-ischemic etiology are independent predictors of RMR.

Time course of secondary mitral regurgitation in patients with heart failure receiving cardiac resynchronization therapy: Impact on long-term outcome beyond left ventricular reverse remodelling

BACKGROUND

The prognostic value of secondary mitral regurgitation (MR) at baseline versus immediately after and several months after cardiac resynchronization therapy (CRT), beyond left ventricular (LV) reverse remodelling, has yet to be investigated.

AIM

To evaluate the clinical significance of secondary MR before and at two timepoints after CRT in a large cohort of consecutive patients with heart failure (HF) and reduced LV ejection fraction.

METHODS

A total of 198 patients were recruited prospectively into a registry, and underwent echocardiography at baseline and immediately after CRT (on the day of hospital discharge). Echocardiography was also performed 9 months after CRT in 172 patients. The impact of significant secondary MR (≥moderate) on all-cause death, cardiovascular death and hospitalization for HF was studied at each stage.

RESULTS

The frequency of significant secondary MR decreased from 23% (n=45) to 8% (n=16) immediately after CRT. Among the 172 patients who underwent echocardiography 9 months after CRT, 17 (10%) had significant secondary MR. During a median follow-up of 48 months, 49 patients died and 36 were hospitalized for HF. Patients with significant secondary MR immediately after or 9 months after CRT had an increased risk of all-cause death, cardiovascular death and hospitalization for HF during follow-up (P<0.05 for all endpoints). After adjustment for LV reverse remodelling, significant secondary MR 9 months after CRT remained associated with an increased risk of all-cause death (adjusted hazard ratio [HR] 3.77; P=0.014), cardiovascular death (adjusted HR 5.36; P=0.037), and hospitalization for HF (adjusted HR 7.33; P=0.001).

CONCLUSIONS

Significant secondary MR despite CRT provides important prognostic information beyond LV reverse remodelling. Further studies are needed to evaluate the potential role of new percutaneous procedures for mitral valve repair in improving outcome in these very high-risk patients.

Left ventricular ejection fraction of < 20%: Too bad for MitraClip© ?

OBJECTIVES

This study sought to investigate whether the percutaneous mitral regurgitation (MR) reduction with the MitraClip® system in end-stage heart failure patients with a left ventricular ejection fraction (LVEF) of <20% also effects beneficial outcome or whether the underlying myogenic problem is leading and therefore of prognostic relevance.

BACKROUND

The interventional treatment of functional mitral regurgitation (FMR) with the MitraClip^® system could improve the clinical and hemodynamic outcome in patients with severely impaired left ventricular function.

MATERIALS AND METHODS

Between 2011 and 2016, a total of 147 patients with FMR were treated with MitraClip^® at our institution. The cohort was divided into two groups: LVEF ≥ 20% (N = 126) and <20% (N = 21). Follow-up assessments included exercise capacity, 6-min walk test, probrain natriuretic peptide-measurement (ProBNP), echocardiography and right heart catheterization. Only three patients with an LVEF ≥ 20% and one patient with an LVEF < 20% were lost for follow-up.

RESULTS

In the vast majority of patients, a reduction from severe to mild MR was demonstrated with no difference between both groups (P = 0.422). At follow-up, both subgroups experienced similar improvements in exercise capacity and hemodynamics. Patients with an LVEF < 20% were on average 5.8 years younger, while mortality rates were comparable in both groups (P = 0.760).

CONCLUSION

By careful selection, even patients in the end stage of advanced LV dysfunction as the result of the underlying myogenic problem and the additional harmful effects of the high volume loading due to the FMR can exhibit significant clinical and hemodynamic improvement after MitraClip^© therapy.

Resolution of Cardiogenic Shock Using Echocardiography-Guided Pacing Optimization in Intensive Care: A Case Series

OBJECTIVE

Inotropic and vasopressor drugs are routinely used in critically ill patients to maintain adequate blood pressure and cardiac output in patients with cardiogenic shock although potentially at the expense of increasing myocardial oxygen demand. Pacing optimization has been demonstrated as effective in reducing catecholamine requirements in patients with chronic heart failure by improving cardiac efficiency; however, there are no reports relating to the effectiveness of pacemaker optimization on cardiac output in critically ill patients with cardiogenic shock in the intensive care.

DATA SOURCES

Retrospective data analysis.

STUDY SELECTION

Twenty-bed adult tertiary cardiothoracic ICU, university hospital.

DATA EXTRACTION

Eight sequential patients receiving dual chamber pacemaker with DDD modality with cardiogenic shock and hemodynamic instability refractory to catecholamines underwent echocardiography-guided pacemaker optimization of cardiac output. An iterative method with Doppler echocardiography was used to assess changes in cardiac output, left ventricular filling time, ejection time, total isovolumic time, mitral regurgitation, ejection fraction, and blood pressure at different increments of heart rate, and atrioventricular and interventricular delay. All results are shown as median (minimum/maximum level) or mean ± SD.

DATA SYNTHESIS

Using echocardiography-guided pacemaker optimization on cardiac output, the cardiac output increased from 3.2 (2.3/3.8) to 5.7 L/min (4.85/7.1) and cardiac index from 1.64 (1.1/1.9) to 2.68 L/min/m (2.1/3.2) and the total isovolumic time reduced from 22.8 to normal values (<14). In association, the glomerular filtration rate increased significantly except in one patient with stage IV chronic kidney disease. All inotropes and vasopressors were discontinued within 12 hours of pacemaker optimization on cardiac output, and all patients were discharged from the ICU within 1 week.

CONCLUSIONS

Echocardiography-guided pacemaker optimization of cardiac output is a feasible bedside therapeutic option, which should be considered when standard medical treatments are insufficient for the treatment of cardiogenic shock refractory to inotropic support, thereby minimizing the detrimental effect of catecholamines.

Implantation of CARILLON® Mitral Contour System with transvenous left ventricular lead in place

BACKGROUND

Cardiac resynchronisation therapy (CRT) is an established treatment option for chronic heart failure patients with left bundle branch block. Although a concomitant functional mitral regurgitation is often reduced by CRT, many patients need additional mitral valve repair. Placing a CARILLON^® Mitral Contour System (CMCS) over a transvenous CRT lead is currently not recommended, since both of them are implanted in the coronary sinus (CS). The aim of this study was to investigate the feasibility of sequential implantation of a transvenous LV lead followed by CMCS implantation, and to assess LV lead performance and possibility of extraction.

METHODS AND RESULTS

Standard transvenous LV leads were implanted in the CS of five female sheep. After establishing regular anatomical position with stable electrical parameters of the LV lead, a CMCS was additionally implanted in the CS. After an observation period of 100 days, lead performance and positions of lead and CMCS were studied. Sequential implantation of the two components was feasible in sheep. After 100 days, all leads showed regular measurements of impedance, threshold, and sensing. There was no migration of either the LV lead or the CMCS. In all cases, the LV lead could be completely extracted without migration of the CMCS. There were no acute or long-term complications.

CONCLUSIONS

In an animal model of healthy adult sheep, implantation of CMCS with a transvenous LV lead already in place was feasible and without major problems with either the CMCS or the LV lead. Electrical performance of the LV leads was excellent. All LV leads could be extracted without migration of the CMCS.

Cardiac resynchronization therapy before and after MitraClip implantation: An advantageous upgrading to reduce mitral regurgitation

MitraClip therapy has been proposed as therapeutic option in selected patients with degenerative or functional mitral regurgitation (FMR), leading to clinical and prognostic benefits. Previous studies demonstrated the safety and the efficacy of MitraClip therapy on symptoms and left ventricular remodeling in cardiac resynchronization therapy (CRT) non-responder patients. We report a case of a CRT non-responder patient treated with MitraClip implantation followed by a new upgrading of the CRT for persistent FMR at the follow-up. The optimization of the interventricular delay, guided by echocardiographic parameters, resulted in a significant clinical and functional benefit. Echo-guided CRT upgrading can provide additive efficacy for patients in whom MitraClip implantation does not significantly improve FMR and symptoms.

Established interventions for mitral valve regurgitation. Current evidence

Severe mitral regurgitation (MR) is a growing medical challenge in today's aging population, leading to increased health expenditure due to the resultant morbidity and mortality. Surgery, either replacement or repair, has been the mainstay of therapy for primary MR. In high-risk or inoperable patients, treatment was limited to medical therapy until 2008. Since then, alternative percutaneous therapies have been introduced and have proven to be safe and effective in patients with secondary MR. Edge-to-edge repair with the MitraClip system is applied worldwide for primary and secondary MR. Randomized data do not support its application in low-risk patients with primary MR. Results from ongoing and future randomized trials will clarify its impact on important clinical endpoints in high-risk and inoperable patients. The Carillon device is a percutaneous indirect annuloplasty technique introduced in 2009 for secondary MR. Clinical data for the novel Cardioband system, using a different intra-atrial annuloplasty technique, have been gathered from more than 40 patients and the system recently received CE mark approval. Other percutaneous repair devices and implantable valves are under development and may be introduced into clinical practice soon. The percutaneous interventional therapy of MR is a highly dynamic field of cardiovascular medicine and has the potential to improve quality of life as well as morbidity and mortality in selected patients.

Functional Mitral Regurgitation: Appraising the Evidence Behind Recommended Treatment Strategies

Functional mitral regurgitation (MR) is the most common type of MR encountered in clinical practice. Because the disease arises from the ventricular aspect of the mitral valve apparatus, treatment therapies are less defined and outcomes are poor. In this review, the state of evidence for medical and surgical therapy in functional MR is appraised. Future directions for research in this area are also defined.