(Meta)-Analysis of Safety and Efficacy Following Edge-to-Edge Mitral Valve Repair Using the MitraClip System

Midterm results of transventricular mitral valve repair: Single-center experience

OBJECTIVE

The study objective was to evaluate the midterm outcomes of transventricular mitral valve repair and its association with the initial anatomy of the mitral valve.

METHODS

This nonrandomized observational study included 88 patients (mean age, 60 years; 69% were men) who underwent transventricular mitral valve repair for severe degenerative mitral regurgitation between 2011 and 2017. Mitral valve function was assessed by echocardiography at 1 and 6 months and annually after the procedure. According to the location of mitral valve pathology, all patients were stratified into 4 anatomic types (A, B, C, and D). Results were assessed using Kaplan-Meier method, mixed-effects continuation ratio model, and multivariable Cox regression.

RESULTS

Median follow-up of 42 months (interquartile range, 27-55) was complete for 83 patients (94.3%). There were 3 late deaths: 2 cardiac and 1 noncardiac. Recurrent mitral regurgitation greater than 2+ was observed in 29 patients (33%), and 18 patients (20.5%) underwent repeat surgery. Device success was 82% in type A at 6 months and thereafter; 87%, 85%, and 75% at 6, 12, and 36 months in type B, respectively; and 53% at 1 month and 20% at 24 months in type C. Probability of postoperative mitral regurgitation progression was higher in patients with greater preoperative left ventricular end-diastolic diameter, type B pathology, and type C pathology (P < .05). Risk factors of mitral regurgitation recurrence included increased left ventricle size (hazard ratio, 1.11; 95% confidence interval, 1.04-1.20; P = .001) and type C pathology (hazard ratio, 5.99; 95% confidence interval, 1.87-19.21; P = .003).

CONCLUSIONS

Initial acceptable mitral regurgitation reduction after transventricular mitral valve repair of isolated P2 prolapse was possible but found durable in only 82% at 3 years. Higher risk of mitral regurgitation recurrence occurred with complex degenerative pathology.

MitraClip device for patients with functional mitral valve regurgitation: A systematic review

BACKGROUND

MitraClip device is a novel therapeutic option for patients with degenerative mitral valve regurgitation. Nevertheless, several studies have also focused on the safety and efficacy of this method in functional mitral valve regurgitation (FMR).

AIM

To systematically review all original studies that provided mortality data among FMR patients treated with MitraClip.

MATERIALS AND METHODS

We conducted an in-depth literature search of 3 electronic databases (Medline, Scopus and Cochrane Library) in order to identify studies investigating the efficacy of MitraClip in FMR. Thirty-day and 12-month mortality after MitraClip implantation were the measured outcomes.

RESULTS

Twenty-eight studies, involving 2383 patients, were included. The phenotype of the studied population was characterized by clinical and echocardiographic parameters suggesting severe FMR (NYHA III-IV: 91%, MR≥3+: 98%) with high surgical risk (mean Euroscore: 24.6%). The Mitraclip device was successfully implanted in 95.8% of patients, resulting in a reduction of two or more degrees of MR. Thirty day and 12-month mortality rates were estimated to be 2.3% and 18.9%, respectively.

CONCLUSIONS

MitraClip appears to be a safe therapeutic option for patients with FMR who are considered to be at high surgical risk.

Short-term and 1-year outcomes after MitraClip therapy in functional versus degenerative mitral regurgitation patients: a systematic review and meta-analysis

Background

Differences in short-term and 1-year outcomes of percutaneous edge-to-edge mitral repair between patients with functional and degenerative mitral regurgitation (MR) remain unclear. We performed a systematic review and meta-analysis to investigate the safety and efficacy of MitraClip (MC) in patients with different MR etiologies.

Methods

This study systematically searched three common databases for studies on MC therapy until November 2017. The studies meeting the standard inclusion criteria were included. The data at baseline, short-term and 1-year clinical and echocardiographic outcomes were obtained and analyzed. All data were checked by another reviewer.

Results

Thirteen studies totalling 2,351 patients investigating the short-term and 1-year outcomes of MC in patients with functional MR (FMR) versus degenerative MR (DMR) were included for further analysis. FMR patients presented a higher risk profile at baseline. There was no difference in short-term outcomes between DMR and FMR for post-procedural MR grade 0-2 (76.8% vs. 77.1%; P=0.428), mean trans-mitral gradient (3.92 vs. 3.50 mmHg; P=0.098), 30-day mortality rate (0.05% vs. 0.03%; P=0.118) and 30-day NYHA I-II (85.3% vs. 78.7%; P=0.211). FMR patients had a higher rate of acute procedural success compared to the DMR patient group (91.2% vs. 95.2%; P=0.016). A greater portion of DMR patients implanted two or more MCs than the FMR patients (41.4% vs. 35.7%; P=0.043). For the 1-year outcomes, no difference was found in the mortality rate (13.0% vs. 15.2%; P=0.268) and proportion of patients with post-procedural MR grades 0-2 (75.0% vs. 80.7%; P=0.106).

Conclusions

Despite a higher risk profile in FMR patients, the short-term and 1-year outcomes were not significantly different. We conclude that MC therapy is similar between FMR and DMR patients until 1-year follow-up. Large randomized trials are warranted to fully and further assess the clinical impact of the procedure in these two MR etiologies over a longer period of time.

Three-dimensional transoesophageal echocardiography is crucial for valid assessment of mitral valve leaflet morphology in severe mitral regurgitation prior to interventional repair

BACKGROUND

Interventional mitral valve (MV) repair of severe symptomatic mitral regurgitation (MR) is a therapeutic option in high-risk surgical or inoperable patients. Assessment of the MV remains a crucial part of pre-interventional screening. Three-dimensional transoesophageal echocardiography (3D-TOE) may compensate for well-known pitfalls that occur in 2D-TOE.

PURPOSE

We investigated whether the functional length of the central segments of the posterior and anterior MV leaflets (PML-P2 and AML-A2) is more reliably determined by 3D-TOE full volume datasets (3D-MPR) or orthogonal biplane-imaging (Xplane) when compared to 2D-TOE.

METHODS AND RESULTS

Between February 2014 and August 2015, 265 consecutive patients with moderate to severe symptomatic MR were screened. Seventy patients were judged suitable for interventional MV repair by the in-house Heart-Team. Eventually, 59 patients remained for data analysis. Inter-observer variability was lowest in 3D-MPR followed by Xplane (r = 0.92 and 0.90, p < .001 for both) and highest in Mplane (r = 0.82, p < .001). Mean functional PML-P2 lengths were similar in Xplane (12.6 ± 1.7 mm) and 3D-MPR (12.1 ± 2.0 mm), however, significantly different in 2D-TOE (10.0 ± 2.1 mm, p < .001). 2D-TOE underestimated PML-P2 length with a bias of -2.5 mm compared to Xplane and -1.95 mm compared to 3D-MPR. In contrast, functional AML-A2 length was determined similar across all methods.

CONCLUSIONS

Our results demonstrate the superiority of 3D-TOE over 2D-TOE for accurate MV assessment in MR, especially for the determination of the functional PML length. Erroneous MV leaflet assessment may result in inadequate therapy restriction if the MV is deemed not suitable for interventional repair.

A Risk Model for Prediction of 1-Year Mortality in Patients Undergoing MitraClip Implantation

There is a lack of specific tools for risk stratification in patients who undergo MitraClip implantation. We aimed at combining preprocedural variables with prognostic impact into a specific risk model for the prediction of 1-year mortality in patients undergoing MitraClip implantation. A total of 311 consecutive patients who underwent MitraClip implantation were included. A lasso-penalized Cox-proportional hazard regression model was used to identify independent predictors of 1-year all-cause mortality. A nomogram (GRASP [Getting Reduction of mitrAl inSufficiency by Percutaneous clip implantation] nomogram) was obtained from the Cox model. Validation was performed using internal bootstrap resampling. Forty-two deaths occurred at 1-year follow-up. The Kaplan-Meier estimate of 1-year survival was 0.845 (95% confidence interval, 0.802 to 0.895). Four independent predictors of mortality (mean arterial blood pressure, hemoglobin natural log-transformed pro-brain natriuretic peptide levels, New York Heart Association class IV at presentation) were identified. At internal bootstrap resampling validation, the GRASP nomogram had good discrimination (area under receiver operating characteristic curve of 0.78, Somers' D_xy statistic of 0.53) and calibration (le Cessie-van Houwelingen-Copas-Hosmer p value of 0.780). Conversely, the discriminative ability of the EuroSCORE II (the European System for Cardiac Operative Risk Evaluation II) and the STS-PROM (the Society of Thoracic Surgeons Predicted Risk of Mortality score) was fairly modest with area under the curve values of 0.61 and 0.55, respectively. A treatment-specific risk model in patients who undergo MitraClip implantation may be useful for the stratification of mortality at 1 year. Further studies are needed to provide external validation and support the generalizability of the GRASP nomogram.

A review of comparative studies of MitraClip versus surgical repair for mitral regurgitation

OBJECTIVES

We summarized comparative studies of MitraClip versus surgical repair for mitral regurgitation (MR) with a systematic literature search and meta-analytic estimates.

METHODS

MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched through June 2016. Eligible studies were randomized controlled or observational comparative studies of MitraClip versus surgical repair enrolling patients with MR and reporting early (30-day or in-hospital) or late (≥6-month including early) all-cause mortality. For each study, data regarding all-cause mortality and incidence of recurrent >2+ MR in both groups were used to generate odds ratios (ORs). Alternatively, ORs or hazard ratios (HRs) for mortality and recurrent MR themselves were directly abstracted from each study.

RESULTS

Eight reports of 7 studies comparing MitraClip with surgical repair enrolling a total of 1015 patients with MR were identified and included. Pooled analyses demonstrated significantly higher age and logistic European System of Cardiac Operative Risk Evaluation and significantly lower ejection fraction in the MitraClip than surgical repair group, no significant difference in rate of women and patients with New York Heart Association functional class of >II, no statistically significant difference in early- (OR, 0.54; p=0.08) and late-mortality (HR/OR, 1.17; p=0.46), and significantly higher incidence of recurrent MR in the MitraClip than surgical repair group (HR/OR, 4.80; p<0.00001).

CONCLUSIONS

In patients with MR, the MitraClip procedure achieves similar survival to surgical MV repair despite higher risk profiles. Recurrent MR, however, occurs more frequently (4.8-fold) after the MitraClip than surgical repair.