Intraoperative effects of the Coapsys annuloplasty system in a randomized evaluation (RESTOR-MV) of functional ischemic mitral regurgitation.

Grossi EA, Saunders PC, Woo YJ, Gangahar DM, Laschinger JC, Kress DC, Caskey MP, Schwartz CF, Wudel J. Ann Thorac Surg 80:1706-1711, 2005.

Reviewer: Mark A. Chaney, MD
University of Chicago

Abstract: Functional ischemic mitral regurgitation (MR) frequently arises after myocardial infarction and is characterized by annular enlargement or lateral displacement of the subvalvular apparatus. Coapsys is a ventricular-annular remodeling device designed to treat functional ischemic MR that does not require assist of cardiopulmonary bypass for insertion. Initial intraoperative results of the RESTOR-MV randomized clinical trial are presented. Patients referred for coronary artery bypass grafting with preoperative MR grade of two or greater were studied, excluding those with structural valve abnormalities. The Coapsys device, which consists of two epicardial pads connected by a flexible cord, was surgically implanted in 19 patients. Under epicardial echocardiographic guidance, the cord was passed though the left ventricle and tightened externally to improve leaflet coaptation and stabilize the ventricular wall. Tightening was conducted with color flow Doppler imaging. Patients were 64 ± 9 years old with an ejection fraction of 38 ± 9% and received 2.7 ± 1.1 grafts. Intraoperative MR grade was 2.7 ± 0.8 after induction and was reduced to 0.4 ± 0.7 after implantation (p < 0.0001). Mean epicardial dimension was reduced from 8.5 ± 1.2 to 6.4 ± 0.9 cm (p < 0.0001). Intraoperative MR was reduced in 95% (18 of 19) of patients and 84% (16 of 19) had MR grade 1 or less after implantation. All implants were performed without assist of cardiopulmonary bypass or conversion to standard annuloplasty. No hemodynamic compromise or structural damage to the mitral apparatus was noted. Substantial acute remodeling was noted in the left ventricular dimensions. These investigators conclude that in patients without structural valve disease, the Coapsys device acutely reduces functional MR. Further randomized evaluation will assess long-term stability and compare it with standard annuloplasty techniques.

Comments: Functional ischemic MR results from geometric changes in the mitral annulus and subvalvular apparatus secondary to ischemic myocardial injury. Typically, it involves dilatation of the posterior annulus and displacement of the papillary muscles because of postinfarct ventricular remodeling. Standard surgical therapy for functional ischemic MR usually involves a corrective undersized annuloplasty, which primarily corrects the annulus and improves leaflet coaptation with some effect on ventricular geometry. However, the results of this approach, in association with coronary revascularization, can be disappointing with respect to mortality and recurrent MR.

The Coapsys device provides an opportunity for a novel off-pump treatment of functional ischemic MR. It has the potential to both correct annular dilatation and restore ventricular geometry. This device is currently being evaluated as part of a U.S. Food and Drug Administration - regulated Investigational Device Exemption, randomized, pivotal study with efficacy and safety end-points comparing it with standard mitral valve repair. These investigators document the intraoperative experience of the initial phase of this study, which involved implantation of the device in 19 patients.

The Coapsys device consists of two epicardial pads connected by a flexible suture cord between the papillary muscles that bisects the ventricle. Under epicardial echocardiographic guidance, the cord is passed through the left ventricle and then sequentially tightened to improve leaflet coaptation and stabilize the ventricular wall. Sizing is conducted under real-time color flow Doppler imaging to quantify MR. The suture length is shortened, and the final length is determined by elimination of MR or a maximum shortening of 35%. The procedure is performed without the use of cardiopulmonary bypass.

The treatment of functional ischemic MR remains challenging, with traditional approaches (undersized annuloplasty) yielding mediocre mid-term and long-term results. The concept of the Coapsys device is intriguing because it not only treats the annular abnormality but also attempts to directly restore the subannular ventricular geometry. This report confirms the immediate efficacy of the device, with significant ventricular dimensional reduction at both the annular and subvalvular levels. Further randomized evaluation will assess long-term stability and compare it with standard annuloplasty techniques.

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