Transcatheter reshaping of the mitral annulus in patients with functional mitral regurgitation: one-year outcomes of the MAVERIC trial

Numerical modeling for efficiency and endurance assessment of an indirect mitral annuloplasty device

In recent years, several transcatheter systems have been introduced for treatment of common mitral regurgitation (MR). Such a system that is based on indirect mitral annuloplasty (IMA) is currently indicated for functional MR. Very few clinical studies have been performed to assess the efficiency and durability of such devices, despite their high risk of fracture resulting from ongoing exposure to large cyclic deformations. In this study, numerical models of moderate primary MR were created to test the implantation procedure of a customized IMA device and its sealing efficiency. The ability of the implanted device to reduce systolic leakage was evaluated and affirmed with a model of a more generic device. The long-term durability of the device was tested using a range of Nickel Titanium material properties. Our results demonstrated a considerable reduction in leakage for both the simplified generic device and the more detailed customized device models. The device met different fatigue criteria, confirming its resiliency and safety even after 10 years, even under the harsher conditions of primary MR. This is the first study to assess the performance and fatigue risk of IMA devices for the treatment of more complicated MR conditions. These findings may pave the way for further research to ultimately consider the device in selective cases of PMR.

Mitral Regurgitation in the High-Risk Patient: Integrating an Expanding Armamentarium of Transcatheter Devices Into the Treatment Algorithm

Over the last decade, multiple transcatheter mitral valve repair and replacement strategies have emerged, yet there is only 1 US Food and Drug Administration approved device, the MitraClip (Abbott Vascular, Inc., Santa Clara, CA). Current guidelines support the use of the MitraClip in high or prohibitive surgical risk patients, but there are many patients that are not anatomically suited for the device. This review article discusses the approach to degenerative and functional mitral regurgitation in the high-prohibitive risk patient, how to choose transcatheter treatment options (both approved and investigational), and potential management for therapy failure.

Mortality and Clinical Predictors After Percutaneous Mitral Valve Repair for Secondary Mitral Regurgitation: A Systematic Review and Meta-Regression Analysis

Background

Percutaneous mitral valve repair (PMVR) provides an available choice for patients suffering from secondary mitral regurgitation (SMR), especially those whose symptoms persist after optimal, conventional, heart-failure therapy. However, conflicting results from clinical trials have created a problem in identifying patients who will benefit the most from PMVR.

Objective

To pool mortality data and assess clinical predictors after PMVR among patients with SMR. To this end, subgroup and meta-regression analyses were additionally performed.

Methods

We searched PubMed, EMBASE, and Cochrane databases, and 13 studies were finally included for meta-analysis. Estimated mortality and 95% confidence intervals (CIs) were obtained using a random-effects proportional meta-analysis. We also carried out a meta-regression analysis to clarify the potential influence of important covariates on mortality.

Results

A total of 1,259 patients with SMR who had undergone PMVR were enrolled in our meta-analysis. The long-term estimated pooled mortality of PMVR was 19.3% (95% CI: 13.6–25.1). Meta-regression analysis showed that mortality was directly proportional to cardiac resynchronization therapy (CRT) (β = 0.009; 95% CI: 0.002–0.016; p = 0.009), an effective regurgitant orifice (ERO) (β = 0.009; 95% CI: 0.000–0.018; p = 0.047), and a mineralocorticoid receptor antagonist (MRA) use (β = −0.015; 95% CI: −0.023–−0.006; p < 0.001). Subgroup analysis indicated that patients with preexisting AF (β = −0.002; 95% CI: −0.005– −0.000; p = 0.018) were associated with decreased mortality if they received a mitral annuloplasty device. Among the edge-to-edge repair device group, a higher left ventricular (LV) ejection fraction, or lower LV end-systolic diameter, LV end-systolic volume, and LV end-diastolic volume were proportional to lower mortality.

Conclusion and Relevance

The pooled mortality of PMVR was 19.3% (95% CI: 13.6–25.1). Further meta-regression indicated that AF was associated with a better outcome in conjunction with the use of a mitral annuloplasty device, while better LV functioning predicted a better outcome after the implantation of an edge-to-edge repair device.

Transcatheter Treatment of Mitral Regurgitation

Mitral valve disease, and in particular mitral regurgitation, is a common clinical entity. Until recently, surgical repair and replacement were the only therapeutic options available, leaving many patients untreated mostly due to excessive surgical risk. Over the last number of years, huge strides have been made regarding percutaneous, catheter-based solutions for mitral valve disease. Transcatheter repair procedures have most commonly been used, and in recent years there has been exponential growth in the number of devices available for transcatheter mitral valve replacement. Furthermore, the evolution of these devices has resulted in both smaller delivery systems and a shift towards transeptal access, negating the need for surgical incisions. In line with these advancements, and clinical trials demonstrating promising outcomes in carefully selected cases, recent guidelines have strengthened their recommendations for these devices. It is appropriate, therefore, to now review the current transcatheter repair and replacement devices available and the evidence for their use.

Anatomy and Topography of Coronary Sinus and Mitral Valve Annulus in Functional Mitral Regurgitation

Background

We aimed to investigate the anatomical relationship of the coronary sinus (CS) and the mitral valve annulus (MVA) in patients with or without functional mitral regurgitation (FMR) using a multislice CT (MSCT) software to determine (a) the distance and angle of both CS and MVA plane and (b) the mitral annulus geometry.

Methods

A total of 215 patients with MSCT and CS to MVA topography evaluation were enrolled in this retrospective study.

Results

This patient cohort included 145 patients without FMR (67.4%, FMR ≤ 1+) and 70 patients (32.6%) with clinically relevant FMR (FMR ≥ 2+). Distance and angulation of CS to MVA planes were highly variable. In all groups, no significant correlation was documented between the distance or angle of CS to MVA planes and left ventricular ejection fraction, left ventricular end-diastolic diameter, or left atrial volume. A significant increase in total CS length could be found in patients with FMR ≥ 2+ compared to the FMR ≤ 1+ group. MVA diameter, area, and perimeter were significantly increased in FMR ≥ 2+ compared to FMR ≤ 1+. In the FMR ≥ 2+ cohort 61% showed a distance of CS to MVA plane <7.8 mm and 58% revealed an angle of CS to MVA plane <14.2°.

Conclusion

Distance and angulation of CS to MVA topography using an MSCT approach are similar between patients with or without FMR, while CS length, MVA area, MVA perimeter, anterior-posterior diameter, and intercommissural diameter are significantly increased in all FMR subgroups. However, ~60% of FMR ≥ 2+ patients showed favorable CS to MVA topography for indirect mitral annuloplasty.

Numerical biomechanics modelling of indirect mitral annuloplasty treatments for functional mitral regurgitation

Mitral valve regurgitation (MR) is a common valvular heart disease where an improper closure leads to leakage from the left ventricle into the left atrium. There is a need for less-invasive treatments such as percutaneous repairs for a large inoperable patient population. The aim of this study is to compare several indirect mitral annuloplasty (IMA) percutaneous repair techniques by finite-element analyses. Two types of generic IMA devices were considered, based on coronary sinus vein shortening (IMA-CS) to reduce the annulus perimeter and based on shortening of the anterior-posterior diameter (IMA-AP). The disease, its treatments, and the heart function post-repair were modelled by modifying the living heart human model (Dassault Systèmes). A functional MR pathology that represents ischaemic MR was generated and the IMA treatments were simulated in it, followed by heart function simulations with the devices and leakage quantification from blood flow simulations. All treatments were able to reduce leakage, the IMA-AP device achieved better sealing, and there was a correlation between the IMA-CS device length and the reduction in leakage. The results of this study can help in bringing IMA-AP to market, expanding the use of IMA devices, and optimizing future designs of such devices.

Two-year outcomes from the MitrAl ValvE RepaIr Clinical (MAVERIC) trial: a novel percutaneous treatment of functional mitral regurgitation

AIMS

We report the 2-year outcomes of the MitrAl ValvE RepaIr Clinical (MAVERIC) trial. Functional mitral regurgitation (FMR) is associated with poor outcomes for which there remains an unmet clinical need. ARTO is a transcatheter annular reduction device for the treatment of FMR and an emerging alternative for patients at high surgical risk. The MAVERIC trial was designed to evaluate the safety and performance of the ARTO system in FMR and heart failure (HF).

METHODS AND RESULTS

MAVERIC is an international multicentre, prospective, single arm study enrolling patients with FMR grade ≥ 2, New York Heart Association (NYHA) class ≥II symptoms despite maximal medical therapy. Patients were excluded if they had significant structural mitral valve abnormality or life expectancy <1 year. The primary outcome measures were a composite safety outcome and efficacy defined as mitral regurgitation (MR) reduction 30 days post-procedure. Secondary outcome measures included safety, change in MR grade, NYHA class and hospitalization for HF at 2 years. Forty-five patients were enrolled. The composite safety outcome was met (2/45 adverse events at 30 days) and no device-related deaths occurred at 2-year follow-up. A sustained reduction in MR [grade < 2: 21/31 (68%) vs. 31/31(0%); P < 0.0001], left ventricular end-diastolic volume index (90.0 ± 30 vs. 106 ± 26 mL/m² ; P = 0.004) and anteroposterior diameter (35.5 ± 4.7 vs. 41.4 ± 4.6 mm; P < 0.0001) was seen at 2 years compared to baseline. Progressive symptomatic improvement [NYHA class ≤II: 27/34 (80%) vs. 12/34 (36%); P < 0.0001] and a reduction in HF hospitalizations (19.8% 2 years post vs. 52.3% 2 years prior; P < 0.001) were seen at 2 years compared to baseline.

CONCLUSIONS

The ARTO system is a safe and effective treatment for FMR with reductions in left ventricular end-diastolic volumes sustained to 2 years.

Transcatheter mitral valve repair: an overview of current and future devices

The field of transcatheter mitral valve repair (TMVr) for mitral regurgitation (MR) is rapidly evolving. Besides the well-established transcatheter mitral edge-to-edge repair approach, there is also growing evidence for therapeutic strategies targeting the mitral annulus and mitral valve chordae. A patient-tailored approach, careful patient selection and an experienced interventional team is crucial in order to optimise procedural and clinical outcomes. With further data from ongoing clinical trials to be expected, consensus in the Heart Team is needed to address these complexities and determine the most appropriate TMVr therapy, either single or combined, for patients with severe MR.