Percutaneous Treatment of Mitral Regurgitation

Reasons for conversion and adverse intraoperative events in Endoscopic Port Access™ atrioventricular valve surgery and minimally invasive aortic valve surgery

OBJECTIVES

This study reports the factors that contribute to sternotomy conversions (SCs) and adverse intraoperative events in minimally invasive aortic valve surgery (MI-AVS) and minimally invasive Endoscopic Port Access™ atrioventricular valve surgery (MI-PAS).

METHODS

In total, 3780 consecutive patients with either aortic valve disease or atrioventricular valve disease underwent minimally invasive valve surgery (MIVS) at our institution between 1 February 1997 and 31 March 2016. MI-AVS was performed in 908 patients (mean age 69.2 ± 11.3 years, 45.2% women, 6.2% redo cardiac surgery) and MI-PAS in 2872 patients (mean age 64.1 ± 13.3 years, 46.7% women, 12.2% redo cardiac surgery).

RESULTS

A cumulative total of 4415 MIVS procedures (MI-AVS = 908, MI-PAS = 3507) included 1537 valve replacements (MI-AVS = 896, MI-PAS = 641) and 2878 isolated or combined valve repairs (MI-AVS = 12, MI-PAS = 2866). SC was required in 3.0% (n = 114 of 3780) of MIVS patients, which occurred in 3.1% (n = 28 of 908) of MI-AVS patients and 3.0% (n = 86 of 2872) of MI-PAS patients, respectively. Reasons for SC in MI-AVS included inadequate visualization (n = 4, 0.4%) and arterial cannulation difficulty (n = 7, 0.8%). For MI-PAS, SC was required in 54 (2.5%) isolated mitral valve procedures (n = 2183). Factors that contributed to SC in MI-PAS included lung adhesions (n = 35, 1.2%), inadequate visualization (n = 2, 0.1%), ventricular bleeding (n = 3, 0.1%) and atrioventricular dehiscence (n = 5, 0.2%). Neurological deficit occurred in 1 (0.1%) and 3 (3.5%) MI-AVS and MI-PAS conversions, respectively. No operative or 30-day mortalities were observed in MI-AVS conversions (n = 28). The 30-day mortality associated with SC in MI-PAS (n = 86) was 10.5% (n = 9).

CONCLUSIONS

MIVS is increasingly being recognized as the 'gold-standard' for surgical valve interventions in the context of rapidly expanding catheter-based technology and increasing patient expectations. Surgeons need to be aware of factors that contribute to SC and adverse intraoperative outcomes to ensure that patients enjoy the maximum potential benefit of MIVS and to apply effective risk reduction strategies that encourage safer and sustainable MIVS programmes.

Mitral Valve Adaptation to Isolated Annular Dilation: Insights Into the Mechanism of Atrial Functional Mitral Regurgitation

OBJECTIVES

This study hypothesized that compensatory mitral leaflet area (MLA) adaptation occurs in patients with persistent atrial fibrillation (AF) without left ventricular (LV) dysfunction but has limitations that augment mitral regurgitation (MR). The study also explored whether asymmetrical annular dilation is matched by relative leaflet enlargement.

BACKGROUND

Functional MR occurs in patients with AF and isolated annular dilation, but the relationship of MLA adaptation with annular area (AA) is unknown.

METHODS

Three-dimensional echocardiographic images were acquired from 86 patients with quantified MR: 53 with nonvalvular persistent AF (23 MR+ with moderate or greater MR, 30 MR-) without LV dysfunction or dilation and 33 normal controls. Comprehensive 3-dimensional analysis included total diastolic MLA, adaptation ratios of MLA to annular area and MLA to leaflet closure area, and annular and tenting geometry.

RESULTS

Total MLA was 22% larger in patients with AF than in controls, thus paralleling the increased AA. However, as AA increased, adaptive indices (MLA/AA ratio and ratio of MLA to closure area) plateaued, becoming lowest in MR+ patients (ratio of MLA to closure area = 1.63 ± 0.17 controls, 1.60 ± 0.11 MR-, 1.32 ± 0.10 MR+; p < 0.001). MR increased as the ratio of MLA to closure area decreased (R2 = 0.68; p < 0.001). The posterior-to-anterior MLA ratio remained constant, whereas the posterior-to-anterior mitral annulus perimeter increased (1.21 ± 0.16 controls, 1.32 ± 0.20 MR-, 1.46 ± 0.19 MR+; p < 0.001). Multivariate MR determinants were annular area, total MLA to closure area, and posterior-to-anterior perimeter ratios.

CONCLUSIONS

MLA adaptively increases in AF with isolated annular dilation and normal LV function. This compensatory enlargement becomes insufficient with greater annular dilation, and the leaflets fail to match asymmetrical annular remodeling, thereby increasing MR. These findings can potentially help optimize therapeutic options and motivate basic studies of adaptive growth processes.

The use of imaging in new transcatheter interventions: an EACVI review paper

Transcatheter therapies for the treatment of valve heart diseases have expanded dramatically over the last years. The new developments and improvements in devices and techniques, along with the increasing expertise of operators, have turned the catheter-based approaches for valvular disease into an established treatment option. Various imaging techniques are used during these procedures, but echocardiography plays an essential role during patient selection, intra-procedural monitoring, and post-procedure follow-up. The echocardiographic assessment of patients undergoing transcatheter interventions places demands on echocardiographers that differ from those of the routine evaluation of patients with valve disease, and there is a need for specific expertise for those working in the cath lab. In the context of the current rapid developments and growing use of transcatheter valve therapies, this document intends to update the previous recommendations and address new advancements in imaging, particularly for those involved in any stage of the treatment of patients with valvular heart diseases.

The transcatheter valve technology pipeline for treatment of adult valvular heart disease

The transcatheter valve technology pipeline has started as simple balloon valvuloplasty for the treatment of stenotic heart valves and evolved since the year 2000 to either repair or replace heart valves percutaneously with multiple devices. In this review, the present technology and its application are illuminated and a glimpse into the near future is dared from a physician's perspective.

The Evolving Role of Percutaneous Mitral Valve Repair

BACKGROUND

Mitral regurgitation (MR) is the second leading cause of valvular heart disease in the United States behind aortic stenosis. The percutaneous repair of the mitral valve (MitraClip, Abbott, Inc.) has been approved in the United States since 2013 as an alternative to traditional mitral valve surgery. However, many questions are left unanswered about when to perform this procedure and whom to perform it on.

METHODS

We reviewed major published literature on the MitraClip from 2003-2016 to help guide clinical decision-making. A PubMed search was conducted using the phrase "mitraclip" or "percutaneous mitral valve repair" to identify relevant articles pertaining to the clip as well as surgical valve repair.

RESULTS

The clinical trials EVEREST I and EVEREST II (Endovascular Valve Edge-to-Edge Repair Study) demonstrated the safety and efficacy of the MitraClip but did not prove its superiority to surgical repair in the population studied. Numerous subsequent registries have suggested that the success of the MitraClip varies with the patient population studied. The currently enrolling Cardiovascular Outcomes for Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional MR (COAPT) trial hopes to answer some of these questions.

CONCLUSION

The MitraClip is a new and exciting technology for percutaneously treating disease processes traditionally managed with surgery. The future of the clip and its patient population is dependent on further studies.

Recent developments in percutaneous mitral valve treatment

In recent years, various percutaneous techniques have been introduced for the treatment of mitral regurgitation (MR), including direct leaflet repair, annuloplasty and left ventricular remodeling. Percutaneous mitral repair targets both primary degenerative and secondary mitral valve regurgitation and may be considered in selected high-surgical-risk patients. The assessment of mitral functional anatomy by echocardiography and computed tomography is crucial when selecting the appropriate repair strategy, according to the regurgitant valve lesion and the surrounding anatomy. The ongoing clinical use of new devices in annuloplasty and percutaneous mitral valve replacement is a promising new scenario in the treatment of MR that goes beyond the conventional surgical approach.

Percutaneous mitral valve repair

Nonsurgical treatment of clinically important mitral regurgitation (MR) has evolved tremendously over the past decade. Recent studies of percutaneous mitral valve repair procedures have shown that less invasive procedures are safe and can be effective in selected patients. MitraClip has been studied most extensively. The MitraClip is attached to the middle scallop of the mitral leaflets by a transseptal-transvascular approach. The device approximates the leaflets in an edge-to-edge percutaneous repair technique that diminishes MR, improves functional status, and improves left ventricular remodeling. The subgroup that has the most benefit includes patients with older age, poorer left ventricular function, and functional MR and is considered high risk for surgical valve replacement. Other novel percutaneous mitral valve therapies under investigation include indirect and direct annuloplasty, and ventricular remodeling devices.

Future horizons for catheter-based interventions in adult congenital and structural heart disease

In recent decades, there has been an exponential growth in both the number and range of catheter-based interventions for adult congenital and structural heart disease. In this article, we discuss the rationale for the ongoing development of minimally invasive multidisciplinary interventions; the required training elements necessary to achieve expertise in the field; the cardiac team needed to best perform these interventions; and the currently available and up and coming technologies for performing transcatheter valve therapies.

Beating-heart mitral valve chordal replacement

Replacing open-heart surgical procedures with beating-heart interventions substantially decreases the trauma and risk of a procedure. One of the most challenging procedures to perform on the beating heart is valve repair. To address this need, this paper proposes a tool for replacing mitral valve chordae to correct regurgitation. The chordae is secured to the papillary muscle and leaflet using NiTi tissue anchors that also incorporate an internal adjustment mechanism to enable initial adjustment as well as subsequent readjustment of chordae length. Efficacy of the proposed tool for chordae replacement and reduction of regurgitation was demonstrated in an ex-vivo heart simulator.

Percutaneous transcatheter mitral valve repair: a classification of the technology

Surgical treatment of mitral regurgitation (MR) has evolved from mitral valve replacement (MVR) to repair (MVR(e)), because MVR(e) produces superior long-term outcomes. In addition, MVR(e) can be achieved through minimally invasive approaches. This desire for less invasive approaches coupled with the fact that a significant proportion of patients--especially elderly persons or those with significant comorbidities or severe left ventricular (LV) dysfunction, are not referred for surgery, has driven the field of percutaneous MVR(e). Various technologies have emerged and are at different stages of investigation. A classification of percutaneous MVR(e) technologies on the basis of functional anatomy is proposed that groups the devices into those targeting the leaflets (percutaneous leaflet plication, percutaneous leaflet coaptation, percutaneous leaflet ablation), the annulus (indirect: coronary sinus approach or an asymmetrical approach; direct: true percutaneous or a hybrid approach), the chordae (percutaneous chordal implantation), or the LV (percutaneous LV remodeling). The percutaneous edge-to-edge repair technology has been shown to be noninferior to open repair in a randomized clinical trial (EVEREST II [Endovascular Valve Edge-to-Edge REpair Study]). Several other technologies employing the concepts of direct and indirect annuloplasty and LV remodeling have achieved first-in-man results. Most likely a combination of these technologies will be required for satisfactory MVR(e). However, MVR(e) is not possible for many patients, and MVR will be required. Surgical MVR is the standard of care in such patients, although percutaneous options are under development.

Investigational devices for mitral regurgitation: state of the art

The incidence of mitral regurgitation (MR) is rising as a result of an aging population worldwide. Surgical repair or replacement of the mitral valve remains the standard of care for patients with severe MR as the only approach to achieve sustained relief of symptoms or heart failure. However, the majority of patients with severe MR do not undergo surgery because of high perceived perioperative risk. Recently, there has been great enthusiasm in the pursuit of a less invasive percutaneous approach to the treatment of MR to avoid thoracotomy or cardiopulmonary bypass, even if less efficacious. This article reviews the latest developments of various percutaneous options in the treatment of MR.