One-Year Results Published From EVOLUTION Study of Edwards Monarc Mitral Valve

January 19, 2011—In the Journal of the American College of Cardiology: Cardiovascular Interventions, Jan Harnek, MD, et al have published 1-year results from the EVOLUTION study (2011;4:115–122). The phase 1 study seeks to assess the safety and efficacy of the Monarc percutaneous mitral annuloplasty system (Edwards Lifesciences, Irvine, CA) for treating patients with mitral regurgitation (MR).

The investigators noted that MR is associated with a worsened prognosis in patients with dilated cardiomyopathy. Percutaneous annuloplasty with the Monarc device, implanted within the coronary sinus, is designed to reduce MR through a similar mechanism as surgical mitral annuloplasty, which reduces the septal-lateral dimension of the mitral annulus, resulting in improved leaflet coaptation and a reduction in regurgitation.

As detailed by the EVOLUTION investigators, 72 patients with MR grade 2 were enrolled at eight participating centers in four countries. Clinical evaluation and transthoracic echocardiography were performed at baseline and at 3, 6, and 12 months. Multislice computed tomography and coronary angiography were performed at baseline and at 3 months.

The investigators reported that the Monarc device was implanted in 59 of 72 patients (82%). The primary safety endpoint (freedom from death, tamponade, or myocardial infarction at 30 days) was met in 91% of patients at 30 days and in 82% at 1 year. Computed tomography documented passage of the great cardiac vein over an obtuse marginal artery in 55% of patients and was associated with angiographic coronary artery compression in 15 patients and myocardial infarction in two patients (3.4%). At 12 months, a reduction in MR by one grade was observed in 50% of 22 implanted patients with matched echocardiograms and in 85.7% of seven patients with a baseline MR grade of 3.

The investigators concluded that implantation of the Monarc device in the coronary sinus is feasible and may reduce MR; however, coronary artery compression may occur with patients in whom the great cardiac vein passes over a coronary artery, necessitating strategies in future studies to avoid this occurrence.

Also in the Journal of the American College of Cardiology: Cardiovascular Interventions, Paul T.L. Chiam, MBBS, and Carlos E. Ruiz, MD, have published a classification of technology for percutaneous transcatheter mitral valve repair (2011;4:1–13).

According to the authors of the paper, surgical treatment of MR has evolved from mitral valve replacement to valve repair because repair produces superior long-term outcomes. In addition, repair can be achieved through minimally invasive approaches. This desire for less-invasive approaches, coupled with the fact that a significant proportion of patients—especially people who are elderly, who have significant comorbidities, or who have severe left ventricular (LV) dysfunction—are not referred for surgery, has driven the field of percutaneous mitral valve repair.

As various technologies have emerged and are at different stages of investigation, the authors propose a classification of percutaneous mitral valve repair technologies on the basis of functional anatomy that groups the devices into those targeting the leaflets (percutaneous leaflet plication, coaptation, or 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 authors observed that the EVEREST II (Endovascular Valve Edge-to-Edge Repair Study) clinical trial has shown that percutaneous edge-to-edge repair technology is noninferior to open repair. 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 mitral valve repair. However, repair is not possible for many patients, and valve replacement will be required. Percutaneous options are under development, but for now, surgical mitral valve replacement is the standard of care in such patients, the authors stated.