Treatment of functional mitral valve regurgitation with the permanent percutaneous transvenous mitral annuloplasty system: results of the multicenter international Percutaneous Transvenous Mitral Annuloplasty System to Reduce Mitral Valve Regurgitation in Patients with Heart Failure trial

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.

Left ventricular restoration devices post myocardial infarction

Even in the era of percutaneous reperfusion therapy, left ventricular (LV) remodeling after myocardial infarction (MI) leading to heart failure remains a major health concern. Contractile dysfunction of the infarcted myocardium results in an increased pressure load, leading to maladaptive reshaping of the LV. Several percutaneous transcatheter procedures have been developed to deliver devices that restore LV shape and function. The purposes of this review are to discuss the spectrum of transcatheter devices that are available or in development for attenuation of adverse LV remodeling and to critically examine the available evidence for improvement of functional status and cardiovascular outcomes.

Transcatheter valve interventions in heart failure: new answers to old questions

Heart failure (HF) is often associated with different valve diseases, predominantly functional mitral and tricuspid regurgitation. However, the association between HF and aortic stenosis, particularly low-flow low-gradient aortic stenosis, is not infrequent. Severe mitral and tricuspid regurgitations, as well as aortic stenosis, in HF patients worsen prognosis and left ventricular dilatation and induce further reduction in left ventricular ejection fraction. Transcatheter edge-to-edge mitral and tricuspid valve repair and transcatheter aortic valve implantation could be an important therapeutic option with a satisfactory long-term outcome in HF patients with comorbidities and even in patients with severely depressed ejection fraction.

Eliminating Regurgitation Reduces Fibrotic Remodeling of Functional Mitral Regurgitation Conditioned Valves

Functional mitral regurgitation (FMR) is an insidious and poorly understood condition affecting patients with myocardial disease. While current treatments reduce regurgitation, their ability to reverse mitral valve pathology is unclear. We utilized a pseudo-physiological flow loop to study how repair impacted valve composition. Porcine mitral valves were cultured in control geometry (native papillary muscle position and annular area) or high-tension FMR geometry (5 mm apical and 5 mm lateral displacement of papillary muscles, 65% increased annular area) for 2 weeks. To mimic repair, a reversal condition was created by returning one-week FMR conditioned valves to a non-regurgitant geometry and culturing for 1 week. Valve composition and material properties were analyzed. After two-week culture, FMR conditioned tissues were stiffer and stronger than control and underwent extensive fibrotic remodeling, with increased prolyl-4-hydroxylase, lysyl oxidase, matrix metalloproteinase-1, and decorin. The reversal condition displayed a heterogeneous, leaflet- and orientation-dependent response. Reversal-conditioned anterior leaflets and circumferential tissue sections continued to have significant fibrotic remodeling compared to control, whereas reversal-conditioned posterior leaflets, chordae tendineae, and radial tissue sections had significantly decreased remodeling compared to FMR-conditioned tissues. These findings suggest current repairs only partially reverse pathology, underscoring the need for innovation in the treatment of FMR.

Cardiac resynchronisation therapy after percutaneous mitral annuloplasty

Percutaneous approaches to reduce mitral regurgitation in ischemic cardiomyopathy have stirred interest recently. Patients with ischemic cardiomyopathy and functional mitral regurgitation often meet criteria for cardiac resynchronisation therapy to improve left ventricular function as well as mitral regurgitation, and alleviate symptoms. This case shows that implantation of a pacing lead in the coronary sinus to restore synchronous left and right ventricular contraction is feasible, despite the presence of a remodeling device in the coronary sinus.

Mitral loop cerclage as a variant form of mitral cerclage annuloplasty that adds a device (CSTV) for preventing potential complications: a preclinical proof of concept and feasibility study

AIMS

Although mitral cerclage annuloplasty can reduce mitral regurgitation, the potential risks for erosion of the surrounding tissue or conduction blockage are barriers to human translation. This preclinical study aimed to provide a proof of concept for a novel approach, mitral loop cerclage (MLC), designed to address these shortcomings.

METHODS AND RESULTS

MLC consists of: (1) a novel appliance termed a coronary sinus and tricuspid valve protective device (CSTV) that includes a tension locker, and (2) a nylon-coated, braided stainless steel rope (0.6 mm thick) with a coronary artery protective device in a single unit (cerclage rope). Nine healthy farm swine underwent MLC in short-term (two weeks, n=4) and midterm (six weeks, n=5) survival experiments under X-ray fluoroscopic guidance imaging. The procedural success rate was 100%. MLC resulted in a significant reduction of the septal lateral dimension of the mitral annulus (24.58±2.16 vs. 21.26±1.43 mm, p=0.04) and left ventricular (LV) volume in diastole (75.9±3.9 vs. 70.6±5.0 ml, p=0.04) in the midterm group. No conduction abnormalities or serious complications were noted beyond trivial tricuspid regurgitation in all cases (n=9). Necropsy showed no evidence of tissue erosion and an excellent biocompatibility of the implanted devices.

CONCLUSIONS

MLC, as a novel approach for catheter-based mitral valve repair, appeared feasible in this short-term preclinical model. Further studies with longer follow-up in a cardiomyopathic animal model are needed to verify the clinical feasibility and safety of MLC.

Anatomical considerations of percutaneous transvenous mitral annuloplasty: a novel procedure for treatment of functional mitral regurgitation

Percutaneous transvenous mitral annuloplasty (PTMA) has evolved as a latest procedure for the treatment of functional mitral regurgitation. It reduces mitral valve annulus (MVA) size and increases valve leaflet coaptation via compression of coronary sinus (CS). Anatomical considerations for this procedure were elucidated in the present study. In 40 formalin fixed adult cadaveric human hearts, relation of the venous channel formed by CS and great cardiac vein (GCV) to MVA and the adjacent arteries was described, at 6 points by making longitudinal sections perpendicular to the plane of MVA, numbered 1-6 starting from CS ostium. CS/GCV formed a semicircular venous channel on the atrial side of MVA. Based on the distance of CS/GCV from MVA, two patterns were identified. In 37 hearts, the venous channel at point 2 was widely separated from the MVA compared to the two ends and in three hearts a nonconsistent pattern was observed. GCV crossed circumflex artery superficially. GCV or CS crossed the left marginal artery and ventricular branches of circumflex artery superficially in 17 and 23 hearts, respectively. As the venous channel was related more to the left atrial wall, PTMA devices probably exert an indirect traction on MVA. The arteries crossing deep to the venous channel may be compressed by PTMA device leading to myocardial ischemia. Knowledge of the spatial relations of MVA and a preoperative and postoperative angiogram may help to reduce such complications during PTMA.

Optimal fluoroscopic viewing angles of left-sided heart structures in patients with aortic stenosis and mitral regurgitation based on multislice computed tomography

BACKGROUND

Transcatheter interventions are currently undertaken using "generic" fluoroscopic viewing angles. However, the position and orientation of heart structures may vary across patients and disease-specific remodeling processes.

OBJECTIVE

This study uses multislice computed tomography to determine optimal fluoroscopic viewing angles of the aortic and mitral annuli, the left atrial appendage and the atrial septum. We explored differences between patients with severe aortic stenosis (AS) and severe mitral regurgitation (MR).

METHODS AND RESULTS

The multislice computed tomographies of 28 patients with severe aortic stenosis (AS) and 32 patients with severe functional mitral regurgitation (MR) were analyzed. For each patient, we evaluated the optimal fluoroscopic viewing angles of the aortic and mitral annuli (en face, maximal and minimal diameters, aortic root with right, left and non coronary sinus in center), left atrial appendage orifice (en face, maximal and minimal diameters), and atrial septum (fossa ovalis) en face. The TAVR implantation view with right coronary sinus in center was LAO 9 - CRA 0 in the AS group and LAO 6 - CAU 5 in the MR group (p = NS). AS and MR patients differed significantly with respect to the fluoroscopic angulation of the aortic annulus en face (8.3°), the aortic annulus maximal (17.7°) and minimal (18.5°) diameters, the mitral annulus aorto-mural diameter (11.3°), and the left atrial appendage orifice en face (11.1°) (all p-values<0.05).

CONCLUSION

Optimal fluoroscopic viewing angles of left-sided structures vary considerably between patients. Multislice computed tomography is a valuable tool to determine the most procedurally relevant angulations, with the potential to optimize procedural safety, efficacy and duration.

Meta-analysis of the usefulness of Mitraclip in patients with functional mitral regurgitation

Midterm outcomes for patients presenting with heart failure and functional mitral regurgitation (MR) treated with Mitraclip remain unclear. Pubmed, Medline, and Google Scholar were systematically searched for studies enrolling patients with severe-moderate MR who underwent Mitraclip implantation. All events after at least 6 months were the primary safety end point (including death, rehospitalization for heart failure, and reinterventions), whereas change in the ejection fraction, left ventricular volumes, arterial pulmonary pressure, and left atrial diameters were considered as secondary end points. Meta-regression analysis was performed to evaluate the effect of baseline clinical and echocardiographic parameters on efficacy outcomes: 875 patients were included in 9 studies; 1.48 clips (1.3 to 1.7) for patients were implanted, and after a median follow-up of 9 months (6 to 12), 409 patients (78% [75% to 83%]) were in class New York Heart Association I/II and 57 (11% [8% to 14%]) still had moderate-to-severe MR. Overall adverse events occurred in 137 (26% [20% to 31%]) of the patients and 78 (15% [1% to 17%]) of them died; 6-minute walk test improved by 100 m (83 to 111), whereas a significant reduction in left ventricular volumes and systolic pulmonary pressure was reported. At meta-regression analysis, an increase in left ventricle systolic volumes positively affected reduction of volumes after Mitraclip, whereas atrial fibrillation reduced the positive effect of the valve implantation on ejection fraction on end-diastolic and -systolic volumes. In conclusion, Mitraclip represents an efficacious strategy for patients with heart failure and severe MR. It offers a significant improvement in functional class and in cardiac remodeling, in patients with severely dilated hearts as well, although its efficacy remains limited in the presence of atrial fibrillation.

[Mitral valve interventions: Where do we stand?]

Mitral valve regurgitation (MR) with resulting heart failure is one of the most prevalent types of valvular heart disease. Currently, various approaches to catheter-based therapy of MR are already available for patients deemed to be at high-risk for surgery. Most experience has been gained with the MitraClip® system. Technological developments in the field of catheter-based treatment of MR is advancing at a rapid pace, with treatment modalities suited for patients with both primary and secondary MR. Annuloplasty is the surgical gold standard, particularly for patients with secondary MR. For catheter-based therapy of secondary MR a distinction is made between indirect and direct annuloplasty, with the latter most closely corresponding to surgical ring implantation. Catheter-based mitral valve replacement is technically feasible at present; however, experience is still limited and only few reports have been published. Technological development is markedly slower than in the field of transcatheter aortic valve replacement, predominantly owing to the far more complex structure of the mitral valve. Positive experience has already been gained with catheter-based implantation of prostheses designed for the aortic valve into degenerated mitral valve bioprostheses and failed surgical mitral annuloplasty rings (valve-in-valve and valve-in-ring implantation). Further approaches to catheter-based treatment of MR in high-risk surgical patients are expected in the future.