Percutaneous mitral valve annuloplasty for functional mitral regurgitation: acute results of the first patient treated with the Viacor permanent device and future perspectives

Coronary Sinus-Based Approach to Mitral Regurgitation

Functional, or secondary, mitral regurgitation (FMR) is clinically important because patient with congestive heart failure with FMR have worse clinical outcomes and associated higher risks than patients without FMR. There is interest in finding repair techniques which may modify the mitral valve dysfunction and reduce the clinical impact. Although several devices have taken advantage of the close anatomical relationship between the coronary sinus and the posterior annulus of the mitral valve, in order to provide a cinching force on the mitral annulus, only the Carillon device is currently in use in humans. A double blind randomized trial is currently being done to evaluate the value of this therapy, building upon the favorable result of three prior safety and efficacy trials, which have led to European approval of the device.

Novel Mitral Repair Device for the Treatment of Severe Mitral Regurgitation: Preclinical Ovine Acute and Chronic Implantation Model

Objective

A project is now underway to implement a novel percutaneous mitral repair system for severe mitral regurgitation (MR). The initial phase of the project consists of proof-of-concept by testing device characteristics using open surgical implantation. When surgical proof-of-concept of the intended percutaneous design is completed, a second phase of the project will consist of in vivo testing of the percutaneous transseptal system. The device is currently being designed to fold into a 17F catheter system and to unfold within the left atrium where attachment is accomplished using a reversible anchoring system. The purpose of this study was to show functionality of the device in elimination of MR using the open surgical method.

Methods

We have performed surgical prototype device implantation in 5 acute and 7 chronic sheep preparations. We created a P2-flail model of severe (4+) MR in the 12 sheep. Via a minimally invasive left thoracotomy incision and open repair on cardiopulmonary bypass, the device was implanted to determine efficacy of elimination of severe MR. Implantation was considered successful if 4+ regurgitation was converted to 1+ MR or lower. Left ventriculography and epicardial 2-dimensional/3-dimensional echocardiography were used to assess repair; serial 2-dimensional/3-dimensional transthoracic echocardiography was used to assess long-term mitral repair status.

Results

Twelve sheep had surgical creation of severe (4+) MR by cutting all chordae to the P2 scallop of the mitral valve; this preparation was tested and was found to produce 100% acute fatality without repair of the mitral valve. Five sheep had acute implantation of the device with elimination of regurgitation in 5/5 sheep. Seven sheep had chronic (1–7 month) implantation of the device. The device was tested in the chronic model for clinical status, residual regurgitation, thrombosis, and histopathology. All sheep had mitigation of MR and survived to the intended date of death.

Conclusions

Proof-of-concept of a novel percutaneous mitral repair device has been completed using an ovine P2-flail severe MR model. The device has characteristics that will allow its use in posterior leaflet degenerative disease and functional/secondary MR. Open, minimally invasive, and robotic surgical implantation of the device can also be developed as an alternative to the percutaneous approach.

Treatment of functional mitral valve regurgitation with the permanent percutaneous transvenous mitral annuloplasty system: results of the multicenter international Percutaneous Transvenous Mitral Annuloplasty System to Reduce Mitral Valve Regurgitation in Patients with Heart Failure trial

OBJECTIVES

PTOLEMY-2 was a prospective multicenter phase I single-arm feasibility trial to evaluate the second-generation permanent percutaneous transvenous mitral annuloplasty (PTMA) device in reducing functional mitral regurgitation (MR).

BACKGROUND

Percutaneous MR reduction has been performed through a direct method of clipping and securing the mitral leaflets together or an indirect approach of reducing mitral annular dimension via the coronary sinus. The PTMA device is the only coronary sinus mitral repair device without a static fixation element.

METHODS

Patients with at least moderate functional MR, New York Heart Association functional class II to IV, and left ventricular ejection fraction of 20% to 50% were enrolled at 14 centers in 5 countries. Device effects on patients were assessed by serial echocardiography, quality of life (QOL), and exercise capacity metrics.

RESULTS

A total of 43 patients were recruited, and 30 patients (70%) were implanted with a permanent PTMA device with a mean follow-up of 5.8 ± 3.8 months. The primary safety end point (freedom from death, myocardial infarction, stroke, or emergency surgery) at 30 days was met in 28 patients, whereas 2 patients died of device-related complications. The primary efficacy end point (MR reduction of at least 1.0 grade or reduction of regurgitant orifice area by 0.1 cm(2) or regurgitant volume by 15 mL or regurgitant fraction by 10% compared with baseline) was obtained in 13 patients. No significant changes were noted in MR parameters, ventricular volumes, or QOL. Distance walked on 6 minutes testing at 6-month follow-up increased from 331 ± 167 m to 417 ± 132 m (P = .65). Compared with nonresponders, responders had a higher baseline regurgitant orifice area >0.2 cm(2) (P = .001) and less prior history of myocardial infarction (P = .02), coronary artery bypass surgery (P = .03), and ischemic MR (P = .04).

CONCLUSIONS

Overall, PTMA had mild impact on MR reduction, left ventricular remodeling, QOL, and exercise capacity. During follow-up, the risk/benefit ratio remained suboptimal.