Mitral Valve Repair With the MitraClip®

Michael O Kayatta; Hanna Jensen; Muralidhar Padala; Richard C Gilmore; Vinod H Thourani

Interv Cardiol. 2014;6(6):557-567.

Abstract and Introduction

Abstract

Mitral valve regurgitation is a common disease, traditionally treated with valve repair or replacement using open cardiac surgery. The most common etiologies of mitral regurgitation (MR) include degenerative and functional pathologies. MitraClip® (Abbott Vascular, CA, USA), a new device for transcatheter mitral valve repair, which gained CE mark approval for use in Europe in 2008, is now approved in the USA for use in patients with symptomatic degenerative mitral valve regurgitation who are deemed to be prohibitive risk surgical candidates. For these patients, MitraClip offers a safe and effective treatment option. Currently, trials are underway to assess its efficacy in high surgical risk patients with functional MR. The data from these trials will hopefully provide guidance to physicians to determine which patients would benefit from the device and which patients would benefit from the standard surgical approach. There is evidence that the MitraClip will continue to have an important role in treating both high-risk and nonsurgical patients with degenerative and functional MR now and in the future.

Introduction

Mitral regurgitation (MR), either from primary valve disease (degenerative) or secondary (functional) to left ventricular dysfunction, affects more than 4 million Americans, or almost one in ten people over age 75 years. When moderately severe or severe, MR progresses and results in the deterioration of left ventricular function resulting in congestive heart failure, increased mortality and a significant decrease in quality of life (QoL). Chronic MR also increases the risk of atrial fibrillation and stroke, both of which can have a debilitating impact on patients.^[1] Definitive treatment of this problem traditionally requires surgical intervention, either with repair or replacement of the diseased valve through a median sternotomy or a lateral thoracotomy.^[2] Minimally invasive open-heart techniques such as endoscopic repair through the right chest or robotic mitral valve repair are available but are less frequently used; all surgical approaches require cardiopulmonary bypass.^[3,4]

Given that patients with severe, symptomatic MR often have increased surgical risk due to impaired cardiac function, advanced age and associated comorbidities, newer approaches that do not utilize invasive techniques requiring cardiopulmonary bypass would be welcome. Transcatheter mitral valve repair with MitraClip® (Abbott Vascular, CA, USA) is one such technology that uses femoral venous access to repair the mitral valve without requiring cardiac arrest and is the primary subject of this review.

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Table 1. Dimensions of the MitraClip®.
Dimension	Size (mm)
Closed clip length	15
Grasping width at 120°	17
Clip width at 180°	20
Arm width	5
Arm length (coaptation length)	9

Table 2. Mitral valve anatomy suitable to MitraClip® placement.
Dimension	Size (mm)
Coaptation length	≥2
Coaptation depth	<11
For flail leaflets:
– Flail gap	≤10
– Arm length (coaptation length)	≤15

Box 1. Summary of the EVEREST II trial (MitraClip ® versus surgery).
Patient population 279 patients with severe MR who were candidates for mitral valve surgery. Efficacy Surgical repair decreased MR more than MitraClip ®. In 12-month follow-up, 20% of MitraClip patients required surgery for mitral dysfunction versus 2% in surgical patients. Both groups had improvements in MR, left ventricular indices, heart failure functional class (NYHA) and quality of life, although degree of MR reduction and left ventricular indices were decreased more in the surgical group. When MitraClip reduced MR to ≤2+, the repair was durable at 5 years. Safety Major adverse events in 15% of MitraClip cohort versus 48% of surgical cohort. Most of the adverse events were blood transfusion, but prolonged intubation was also significantly higher in surgical patients. MR: Mitral regurgitation; NYHA: New York Heart Association.

Box 2. Comparison of real-world patients to those in EVEREST II trial.
Older age Higher surgical risk Decreased ejection fraction Much higher percentage of functional mitral regurgitation Higher percentage of New York Heart Association class III–IV heart failure More comorbid conditions

Sidebar

Executive Summary

Mitral regurgitation

Common disease of elderly, with degenerative mitral regurgitation (MR) being most common etiology.
Surgical repair is the current gold standard.

Percutaneous approaches

Percutaneous valve interventions have shown great success in the treatment of mitral stenosis, as well as for aortic and pulmonary valve replacements (e.g., SAPIEN [Edwards, CA, USA], CoreValve [Medtronic, MN, USA], Melody [Medtronic]).
Percutaneous mitral annuloplasty devices, both indirect and direct approaches, are under development, but early results are mixed.
The MitraClip® is a device that simulates the Alfieri repair (edge-to-edge) to treat functional and degenerative MR via a percutaneous approach (without associated annuloplasty).

Implanting the MitraClip

Standard trans-septal access is obtained. Fluoroscopic and echocardiographic guidance are used during the procedure.
Position the device perpendicular to the mitral valve and advance into the left ventricle.
Retract device toward mitral valve and capture leaflets.
Assess reduction in MR immediately with transesophageal echocardiography, while the heart remains beating.
Clip can be removed and repositioned to improve reduction in MR.
Additional Clips can be implanted if necessary.
Surgical options are still preserved.

Clinical evaluation

EVEREST I trial demonstrated clinical safety.
EVEREST II trial showed good success, although not as effective as surgery. Procedure was very safe, and reduced the need for blood transfusion and mechanical ventilation.
In total, 20% of patients required surgery for persistent MR in 12-month follow-up.
When initially success in reducing MR, the Clip showed durability over 5 years.
Few device-related complications, most commonly single leaflet detachment.

Device approval & current practice

CE mark granted in 2008 and FDA approved in 2013. Majority of commercial practice to date has been in Europe.
Functional MR has been treated more often than degenerative (as opposed to EVEREST II trial) in the commercial experience in Europe.
Most patients selected for MitraClip are high-risk surgical candidates.

Future perspective

COAPT and RESHAPE-HF trials underway to demonstrate the benefit of the therapy in high-risk patients with heart failure due to functional mitral regurgitation.
These will compare MitraClip directly to medical therapy. Goal is to reduce mortality and heart-failure admissions.
Future advances could include smaller delivery system and improved design to prevent partial leaflet detachment.