Transcatheter Mitral Valve Repair for Functional Mitral Regurgitation: Coronary Sinus Approach

Surgical outcomes of double-orifice mitral valve repair in patients with atrioventricular canal defects: a systematic review and meta-analysis

INTRODUCTION

Double-orifice mitral valve or left atrioventricular valve is a rare congenital cardiac anomaly that may be associated with an atrioventricular septal defect. The surgical management of double-orifice mitral valve/double-orifice left atrioventricular valve with atrioventricular septal defect is highly challenging with acceptable clinical outcomes. This meta-analysis is aimed to evaluate the surgical outcomes of double-orifice mitral valve/double-orifice left atrioventricular valve repair in patients with atrioventricular septal defect.

METHODS AND RESULTS

A total of eight studies were retrieved from the literature by searching through PubMed, Google Scholar, Embase, and Cochrane databases. Using Bayesian hierarchical models, we estimated the pooled proportion of incidence of double-orifice mitral valve/double-orifice left atrioventricular valve with atrioventricular septal defect as 4.88% in patients who underwent surgical repair (7 studies; 3295 patients; 95% credible interval [CI] 4.2-5.7%). As compared to pre-operative regurgitation, the pooled proportions of post-operative regurgitation were significantly low in patients with moderate status: 5.1 versus 26.39% and severe status: 5.7 versus 29.38% [8 studies; 171 patients]. Moreover, the heterogeneity test revealed consistency in the data (p < 0.05). Lastly, the pooled estimated proportions of early and late mortality following surgical interventions were low, that is, 5 and 7.4%, respectively.

CONCLUSION

The surgical management of moderate to severe regurgitation showed corrective benefits post-operatively and was associated with low incidence of early mortality and re-operation.

Haemodynamic effects of percutaneous mitral valve edge-to-edge repair in patients with end-stage heart failure awaiting heart transplantation

Aims

Functional mitral regurgitation is complicating end‐stage heart failure and potential heart transplantation by increasing pulmonary artery pressures. The aim of the present study was to investigate feasibility and haemodynamic effects of percutaneous mitral valve edge‐to‐edge repair using the MitraClip™ device in patients with end‐stage heart failure awaiting heart transplantation.

Methods and results

In this retrospective study, we identified nine patients suffering from end‐stage heart failure listed for heart transplantation in whom moderate–severe or severe functional mitral regurgitation was recognized and treated with percutaneous mitral valve edge‐to‐edge repair. Twenty‐two patients listed for heart transplantation and presenting with moderate–severe or severe functional mitral regurgitation treated in the pre‐MitraClip™ era served as controls. Patients were analysed at two separate time points: MitraClip™ group: pre‐procedure and post‐procedure (follow‐up: 215 ± 53 days) and control group: study entry with recognition of moderate–severe or severe functional mitral regurgitation (follow‐up: 197 ± 47 days). Percutaneous mitral valve edge‐to‐edge repair with the MitraClip™ was feasible and safe in our high‐risk end‐stage heart failure population. The intervention resulted in significant reduction of mitral regurgitation (grade 3.0 [0.5] to 1.5 [0.5]; P = 0.009), left atrial diameter (51 mm [16] to 49 mm [4]; follow‐up MitraClip™ vs. control group P = 0.0497), pulmonary artery pressures (sPA 50 mmHg [15] to 45 mmHg [10]; P = 0.02; mPA 34 mmHg [8] to 30 mmHg [10]; P = 0.02), and New York Heart Association class (3.5 [1.0] to 3.0 [0.5]; P = 0.01) and improved mixed‐venous oxygen saturation (57% [11] to 55% [7]; follow‐up MitraClip™ vs. control group P = 0.02). No changes in the control group were observed.

Conclusions

MitraClip™ implantation as ‘bridge‐to‐transplant’ strategy in patients with end‐stage heart failure and severe functional mitral regurgitation awaiting heart transplantation is feasible and appears to result in favourable haemodynamic effects.

Percutaneous Mitral Annuloplasty

Percutaneous mitral valve therapies are emerging as an alternative option for high-risk patients who are not good candidates for conventional open-heart surgery. Recently, multiple technologies and diversified approaches have been developed and are under clinical study or in preclinical development. This article on transcatheter mitral annuloplasty devices, describes the different technologies, and reports on the initial clinical and preclinical experiences.

A systematic review and meta-analysis of surgical outcomes following mitral valve surgery in octogenarians: implications for transcatheter mitral valve interventions

AIMS

To evaluate the outcomes of mitral valve surgery in octogenarians with severe symptomatic mitral regurgitation (MR).

METHODS AND RESULTS

We performed a systematic review and meta-analysis of data on octogenarians who underwent mitral valve replacement (MVR) or mitral valve repair (MVRpr). Our search yielded 16 retrospective studies. Using Bayesian hierarchical models, we estimated the pooled proportion of 30-day mortality, postoperative stroke, and long-term survival. The pooled proportion of 30-day postoperative mortality was 13% following MVR (10 studies, 3,105 patients, 95% credible interval [CI] 9-18%), and 7% following MVRpr (six studies, 2,642 patients, 95% CI: 3-12%). Furthermore, pooled proportions of postoperative stroke were 4% (six studies, 2,945 patients, 95% CI: 3-7%) and 3% (three studies, 348 patients, 95% CI: 1-8%) for patients undergoing MVR and MVRpr, respectively. Pooled survival rates at one and five years following MVR (four studies, 250 patients) were 67% (95% CI: 50-80%) and 29% (95% CI: 16-47%), and following MVRpr (three studies, 333 patients) were 69% (95% CI: 50-83%) and 23% (95% CI: 12-39%), respectively.

CONCLUSIONS

Surgical treatment of MR in octogenarians is associated with high perioperative mortality and poor long-term survival with an uncertain benefit on quality of life. These data highlight the importance of patient selection for operative intervention and suggest that future transcatheter mitral valve therapies such as transcatheter mitral valve repair (TMVr) and/or transcatheter mitral valve implantation (TMVI), may provide an alternative therapeutic approach in selected high-risk elderly patients.

Management-oriented classification of mitral valve regurgitation

Mitral regurgitation (MR) has previously been classified into rheumatic, primary, and secondary MR according to the underlying disease process. Carpentier's/Duran functional classifications are apt in describing the mechanism(s) of MR. Modern management of MR, however, depends primarily on the severity of MR, status of the left ventricular function, and the presence or absence of symptoms, hence the need for a management-oriented classification of MR. In this paper we describe a classification of MR into 4 phases according to LV function: phase I = MR with normal left ventricle, phase II = MR with normal ejection fraction (EF) and indirect signs of LV dysfunction such as pulmonary hypertension and/or recent onset atrial fibrillation, phase III = EF ≥ 30%-< 50% and/or mild to moderate LV dilatation (ESID 40-54 mm), and phase IV = EF < 30% and/or severe LV dilatation (ESDID ≥ 55 mm). Each phase is further subdivided into three stages: stage "A" with an effective regurgitant orifice (ERO) < 20 mm, stage "B" with an ERO = 20-39 mm, and stage "C" with an ERO ≥ 40 mm. Evidence-based indications and outcome of intervention for MR will also be discussed.

Quadripolar left ventricular lead implantation through the anchor struts of a mitral valve annuloplasty device

We describe cardiac resynchronization therapy in a patient with a mitral valve annuloplasty device in situ for functional mitral regurgitation. We successfully implanted a left ventricular lead through a mitral valve annuloplasty device anchor into the coronary sinus and then through the struts of the device's proximal anchor.

MitraClip catheter-based mitral valve repair system

The ongoing evolution of transcatheter valve technology is impressive. Mitral valve regurgitation is the most common type of heart valve insufficiency and mitral valve surgery is, next to aortic valve surgery, the second leading valvular surgical procedure in the western world. However, there is a large patient population suffering from mitral valve regurgitation that is currently not treated with heart surgery because of significant morbidity and mortality risks. This large underserved patient population could benefit from a less invasive treatment. The MitraClip system (Abbott Vascular, Menlo Park, CA, USA) is the first commercially available medical technology providing a catheter-based nonsurgical repair alternative for patients suffering from mitral valve regurgitation and has the greatest clinical experience compared with other alternative devices. The device is currently in late-stage clinical trials in the USA and has received the CE mark.

Transcatheter cardiac valve interventions

Currently aortic valve replacement is performed for patients with severe aortic stenosis and symptoms or objective pathophysiologic consequences such as left ventricular dysfunction. For transcatheter mitral valve interventions, the complex pathophysiology of mitral regurgitation with varying causes along with challenging imaging and delivery issues has led to slower than anticipated clinical introduction. Transcatheter pulmonary valve intervention was primarily designed to treat the difficult problem of right ventricular to pulmonary artery conduit stenosis in the congenital population. These techniques are reviewed in this article.

Magnetic resonance cardiac vein imaging: relation to mitral valve annulus and left circumflex coronary artery

OBJECTIVES

To evaluate in vivo anatomical relationships between the coronary sinus-great cardiac vein (CS-GCV), the mitral valve annulus (MVA), and left circumflex coronary artery (LCX) with cardiovascular magnetic resonance.

BACKGROUND

The CS-GCV has become an anatomical structure of interest because it provides a way of access to the heart for a number of interventional procedures. Previous reports demonstrate that the postulated close anatomical proximity of the CS-GCV to the MVA does not always hold true in patients, both in autopsy specimens and in vivo by computed tomography.

METHODS

In 31 participants (24 volunteers and 7 patients; 15 men; 42 +/- 19 years), cardiovascular magnetic resonance was performed for noninvasive evaluation of the coronary sinus and of the coronary arteries using whole-heart imaging and intravascular contrast agents. Three-dimensional reconstructions, standard orthogonal planes, and unprocessed raw data were used to assess CS-GCV anatomy and its relation to the MVA and the LCX along their entire course.

RESULTS

The CS-GCV was located behind the left atrium in all examined participants, at a minimum distance of 8.6 +/- 3.9 mm from the MVA. In 80% of the participants, the LCX crossed the CS-GCV inferiorly, between the CS-GCV and the MVA. The CS-GCV and the LCX had a parallel course for 26.2 +/- 23.0 mm, with great variability of location and length. In several participants, the CS-GCV had a long parallel course, but in other participants, the LCX crossed below the CS-GCV at a discrete point.

CONCLUSIONS

In all participants, the CS-GCV coursed behind the left atrium rather than behind the MVA. In the majority of the participants, the LCX coursed between the CS-GCV and the MVA. These anatomical relationships should be kept in mind when referring a patient for interventional procedures requiring the access to the CS-GCV, and cardiovascular magnetic resonance might provide important information for the selection of candidates for these procedures.

Percutaneous mitral annuloplasty: an anatomic study of human coronary sinus and its relation with mitral valve annulus and coronary arteries

BACKGROUND

To allow performance of "stand-alone" mitral annuloplasty with minimal invasiveness, percutaneous techniques consisting of delivery into the coronary sinus (CS) of devices intended to shrink the mitral valve annulus have recently been tested in animal models. These techniques exploit the anatomic proximity of the CS and mitral valve annulus in ovine or dogs. Knowledge of a detailed anatomic relationship between the CS, coronary arteries, and mitral valve annulus in humans is essential to define the safety and efficacy of percutaneous techniques in clinical practice. We sought to determine the qualitative and quantitative anatomic relationships between CS and surrounding structures in human hearts.

METHODS AND RESULTS

The distance from the CS to the mitral valve annulus and the relationship between the CS and surrounding structures were studied in 61 excised cadaveric human hearts. Maximal distance from the CS to the mitral valve annulus was found to be up to 19 mm (mean, 9.7+/-3.2 mm). A diagonal or ramus branch, main circumflex artery, or its branches were located between anterior interventricular vein/CS and the mitral valve annulus in 16.4% and 63.9% of cases, respectively.

CONCLUSIONS

Surgical anatomy suggests that in humans the CS is located behind the left atrial wall at a significant distance from the mitral valve annulus. Percutaneous mitral annuloplasty devices probably shrink the mitral valve annulus only by an indirect traction mediated by the left atrial wall; a theoretical risk of compressing coronary artery branches exists. Chronic studies are needed to address this problem and to determine long-term efficacy of such methods.