Treatment of Functional Mitral Regurgitation

Beyond Medical Therapy-An Update on Heart Failure Devices

Heart failure (HF) is a complex and progressive disease marked by substantial morbidity and mortality rates, frequent episodes of decompensation, and a reduced quality of life (QoL), with severe financial burden on healthcare systems. In recent years, several large-scale randomized clinical trials (RCTs) have widely expanded the therapeutic armamentarium, underlining additional benefits and the feasibility of rapid titration regimens. This notwithstanding, mortality is not declining, and hospitalizations are constantly increasing. It is widely acknowledged that even with guideline-directed medical therapy (GDMT) on board, HF patients have a prohibitive residual risk, which highlights the need for innovative treatment options. In this scenario, groundbreaking devices targeting valvular, structural, and autonomic abnormalities have become crucial tools in HF management. This has led to a full-fledged translational boost with several novel devices in development. Thus, the aim of this review is to provide an update on both approved and investigated devices.

Predictive Factors of Cardiac Mortality Following TEER in Patients with Secondary Mitral Regurgitation

Background: Transcatheter edge-to-edge mitral valve repair (TEER) has emerged as a viable approach to addressing substantial secondary mitral regurgitation. In the contemporary landscape where ultimate heart failure-specific therapies, such as cardiac replacement modalities, are available, prognosticating a high-risk cohort susceptible to early cardiac mortality post-TEER is pivotal for formulating an effective therapeutic regimen. Methods: Our study encompassed individuals with secondary mitral regurgitation and chronic heart failure enlisted in the multi-center (Optimized CathEter vAlvular iNtervention (OCEAN)-Mitral registry. We conducted an assessment of baseline variables associated with cardiac death within one year following TEER. Results: Amongst the 1517 patients (median age: 78 years, 899 males), 101 experienced cardiac mortality during the 1-year observation period after undergoing TEER. Notably, a history of heart failure-related admissions within the preceding year, utilization of intravenous inotropes, and elevated plasma B-type natriuretic peptide levels emerged as independent prognosticators for the primary outcome (p < 0.05 for all). Subsequently, we devised a novel risk-scoring system encompassing these variables, which significantly stratified the cumulative incidence of the 1-year primary outcome (16%, 8%, and 4%, p < 0.001). Conclusions: Our study culminated in the development of a new risk-scoring system aimed at predicting 1-year cardiac mortality post-TEER.

Prognosis for Mitral Valve Repair Surgery in Functional Mitral Regurgitation

Purpose: Our aim was to evaluate the development of new significant mitral regurgitation and long-term survival after mitral repair surgery in functional mitral regurgitation.

Methods: A retrospective observational analysis of the recurrence of functional mitral regurgitation (ischemic and nonischemic) and global mortality during follow-up of 176 patients who underwent mitral repair surgery between 1999 and 2018 in our center was conducted.

Results: The etiology of functional mitral regurgitation was ischemic in 55.7% of cases. After surgery, mitral regurgitation was 0-I in 92.3% of cases. We conducted a long-term clinical follow-up of a mean 42.2 months and an echocardiographic follow-up of a mean 41.8 months. We observed mitral regurgitation of at least grade II in 52 patients (36.9%). Survival at 1, 3, and 5 years was 78.8%, 66.7%, and 52.3%, respectively. Predictive factors for global mortality were age (hazard ratio = 1.038, p = 0.01) and a depressed preoperative ejection fraction. After a competing risk analysis, we found the only predictive factor for the recurrence of mitral regurgitation in our series to be age (sub-hazard ratio = 1.03, 95% confidence interval = 1.01–1.06, p = 0.016).

Conclusion: Repair surgery for functional mitral regurgitation shows age as the only independent predictor of recurrence. Age and depressed ejection fraction were predictors of mortality.

The Art of SAPIEN 3 Transcatheter Mitral Valve Replacement in Valve-in-Ring and Valve-in-Mitral-Annular-Calcification Procedures

The SAPIEN 3 is the only transcatheter heart valve commercially available for compassionate transcatheter mitral valve replacement in patients with previous mitral surgical rings and mitral annular calcification (valve in ring [VIR] and valve in mitral annular calcification [VIM]). Reported outcomes have been inconsistent or poor. The review provides an overview of the authors' approach to achieve largely consistent results despite the intrinsic limitations of SAPIEN 3 VIM and VIR. The approach includes bedside modifications of the valve implant, the delivery system, and of the cardiac substrate itself. Until purpose-built devices are readily available, VIR and VIM procedures will require aggressive multidisciplinary cooperation, meticulous planning and execution, and postprocedure management by experienced, high-volume operators.

Outcomes of transcatheter mitral valve repair for secondary mitral regurgitation by severity of left ventricular dysfunction

BACKGROUND

In the COAPT trial, transcatheter mitral valve repair with the MitraClip plus maximally tolerated guideline-directed medical therapy (GDMT) improved clinical outcomes compared with GDMT alone in symptomatic patients with heart failure (HF) and 3+ or 4+ secondary mitral regurgitation (SMR) due to left ventricular (LV) dysfunction.

AIMS

In this COAPT substudy, we sought to evaluate two-year outcomes in HF patients with reduced LV ejection fraction (HFrEF; LVEF ≤40%) versus preserved LVEF (HFpEF; LVEF >40%) and in those with severe (LVEF ≤30%) versus moderate (LVEF >30%) LV dysfunction.

METHODS

The principal effectiveness outcome was the two-year rate of death from any cause or HF hospitalisations (HFH). Subgroup analysis with interaction testing was performed according to baseline LVEF; 472 patients (82.1%) had HFrEF (mean LVEF 28.0%±6.2%; range 12% to 40%) and 103 (17.9%) had HFpEF (mean LVEF 46.6%±4.9%; range 41% to 65%), while 292 (50.7%) had severely depressed LVEF (LVEF ≤30%; mean LVEF 23.9%±3.8%) and 283 (49.3%) had moderately depressed LVEF (LVEF >30%; mean LVEF 39.0%±6.8%).

RESULTS

The two-year rate of death or HFH was 56.7% in patients with HFrEF and 53.4% with HFpEF (HR 1.16, 95% CI: 0.86-1.57, p=0.32). MitraClip reduced the two-year rate of death or HFH in patients with HFrEF (HR 0.50, 95% CI: 0.39-0.65) and HFpEF (HR 0.60, 95% CI: 0.35-1.05), pint=0.55. MitraClip was consistently effective in reducing the individual endpoints of mortality and HFH, improving MR severity, quality of life, and six-minute walk distance in patients with HFrEF, HFpEF, LVEF ≤30%, and LVEF >30%.

CONCLUSIONS

In the COAPT trial, among patients with HF and 3+ or 4+ SMR who remained symptomatic despite maximally tolerated GDMT, the MitraClip was consistently effective in improving survival and health status in patients with severe and moderate LV dysfunction and those with preserved LVEF.

Functional Mitral Regurgitation Outcome and Grading in Heart Failure With Reduced Ejection Fraction

OBJECTIVES

This study aims to define excess-mortality linked to functional mitral regurgitation (FMR) quantified in routine-practice.

BACKGROUND

Appraisal of FMR in heart failure with reduced ejection fraction (HFrEF) is challenging because risks of excess mortality remain uncertain and guidelines diverge.

METHODS

Cases of HFrEF (ejection-fraction <50%) Stage B-C that were diagnosed between 2003 and 2011 and had routine-practice FMR quantitation (FMR cohort, n = 6,381) were analyzed for excess mortality thresholds/rates within the cohort and in comparison to the general population. These were also compared to those of a degenerative mitral regurgitation (DMR) simultaneous cohort (DMR cohort, n = 2,416).

RESULTS

In the FMR cohort (age: 70 ± 11 years, ejection fraction: 36 ± 10%, effective regurgitant orifice area [EROA]: 0.09 ± 0.13 cm²), EROA distribution was skewed towards low-values (≥0.40 cm² in only 8% vs 38% for the DMR cohort; P < 0.0001). One-year mortality was high (15.6%), increasing steeply from 13.3% without FMR to 28.5% with EROA ≥0.30 cm² (adjusted odds ratio: 1.57 [95% CI: 1.19-2.97]; P = 0.001). In the long term, 3,538 FMR cohort patients died with excess mortality threshold ∼0.10 cm² (vs ∼0.20 cm² in the DMR cohort), with 0.10 cm² EROA increments independently associated with considerable mortality increment (adjusted HR: 1.11 [95% CI: 1.08-1.15]; P < 0.0001) and with no detectable interaction. Compared to the general population, FMR excess mortality increased exponentially with higher EROA (risk ratio point estimates 2.8, 3.8, and 5.1 at EROA 0.20, 0.30, and 0.40 cm², respectively), and was much steeper than that of the DMR cohort (P < 0.0001). In nested models, individualized EROA was the strongest FMR survival marker, and a new expanded FMR grading scale based on 0.10 cm² EROA increments provided incremental power over current American Heart Association-American College of Cardiology/European Society of Cardiology guidelines (all P < 0.03).

CONCLUSIONS

In HFrEF, FMR is skewed towards smaller EROA. Nevertheless, when measured in routine practice, EROA is the strongest independent FMR determinant of survival after diagnosis. Excess mortality increases exponentially above the threshold of 0.10 cm², with a much steeper slope than in DMR, for any EROA increment. An expanded EROA-based stratification, superior to existing grading schemes in determining survival, should allow guideline harmonization.

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.

Importance of Myocardial Fibrosis in Functional Mitral Regurgitation: From Outcomes to Decision-Making

Functional mitral regurgitation (FMR) is a common and complex valve disease, in which severity and risk stratification is still a conundrum. Although risk increases with FMR severity, it is modulated by subjacent left ventricular (LV) disease. The extent of LV remodeling and dysfunction is traditionally evaluated by echocardiography, but a growing body of evidence shows that myocardial fibrosis (MF) assessment by cardiac magnetic resonance (CMR) may complement risk stratification and inform treatment decisions. This review summarizes the current knowledge on the comprehensive evaluation that CMR can provide for patients with FMR, in particular for the assessment of MF and its potential impact in clinical decision-making.

Conflicting findings between the Mitra-Fr and the Coapt trials: Implications regarding the cost-effectiveness of percutaneous repair for heart failure patients with severe secondary mitral regurgitation

PURPOSE

Two randomized controlled trials (RCTs), Mitra-Fr and Coapt, evaluating the benefit of percutaneous repair (PR) for heart failure (HF) patients with severe mitral regurgitation, have led to conflicting results. We aimed to evaluate the impact of these trial results on the cost-effectiveness of PR using effectiveness inputs from the two RCTs.

METHODS

We developed a time varying Markov type model with three mutually exclusive health states: alive without HF hospitalisation, alive with HF hospitalisation, and dead. Clinically plausible extrapolations beyond observed data were obtained by developing parametric modelling for overall survival and HF hospitalisations using published data from each trial. We adopted the perspective of the French Health System and used a 30-year time horizon. Results were expressed as € / quality-adjusted life year (QALY) gained using utility inputs from literature.

FINDINGS

Results are presented using treatment efficacy measures from Mitra-F and Coapt trials respectively. With the Mitra-Fr data, after annual discounting, the base case model generated an incremental 0.00387 QALY at a cost of €25,010, yielding an incremental cost effectiveness ratio (ICER) of €6,467,032 / QALY. The model was sensitive to changes made to model inputs. There was no potential of PR being cost-effective. With the Coapt data, the model generated 1.19 QALY gain at a cost of €26,130 yielding an ICER of €21,918 / QALY and at a threshold of >€50,000/QALY PR had a probability of 1 of being cost-effective.

IMPLICATIONS

Cost effectiveness results were conflicting; reconciling differences between trials is a priority and could promote optimal cost effectiveness analyses and resource allocation.

Percutaneous repair or medical treatment for secondary mitral regurgitation: outcomes at 2 years

AIMS

The MITRA-FR trial showed that among symptomatic patients with severe secondary mitral regurgitation, percutaneous repair did not reduce the risk of death or hospitalization for heart failure at 12 months compared with guideline-directed medical treatment alone. We report the 24-month outcome from this trial.

METHODS AND RESULTS

At 37 centres, we randomly assigned 304 symptomatic heart failure patients with severe secondary mitral regurgitation (effective regurgitant orifice area >20 mm² or regurgitant volume >30 mL), and left ventricular ejection fraction between 15% and 40% to undergo percutaneous valve repair plus medical treatment (intervention group, n = 152) or medical treatment alone (control group, n = 152). The primary efficacy outcome was the composite of all-cause death and unplanned hospitalization for heart failure at 12 months. At 24 months, all-cause death and unplanned hospitalization for heart failure occurred in 63.8% of patients (97/152) in the intervention group and 67.1% (102/152) in the control group [hazard ratio (HR) 1.01, 95% confidence interval (CI) 0.77-1.34]. All-cause mortality occurred in 34.9% of patients (53/152) in the intervention group and 34.2% (52/152) in the control group (HR 1.02, 95% CI 0.70-1.50). Unplanned hospitalization for heart failure occurred in 55.9% of patients (85/152) in the intervention group and 61.8% (94/152) in the control group (HR 0.97, 95% CI 0.72-1.30).

CONCLUSIONS

In patients with severe secondary mitral regurgitation, percutaneous repair added to medical treatment did not significantly reduce the risk of death or hospitalization for heart failure at 2 years compared with medical treatment alone.