Beating-Heart Mitral Valve Repair Using Novel Implant Device

Study Questions:

What are the safety and short-term performance characteristics of the Harpoon Mitral Valve Repair System (MVRS) for beating-heart expanded polytetrafluoroethylene (ePTFE) chordal implantation to treat severe degenerative mitral regurgitation (MR)?

Methods:

The TRACER (Mitral TransApical NeoCordal Echo-Guided Repair) trial is a prospective, nonrandomized, multicenter study designed to test the safety and performance of the Harpoon MVRS. In the trial, 30 consecutive patients with severe degenerative MR due to isolated posterior leaflet prolapse at six clinical centers in Europe were treated under transesophageal echocardiography (TEE) guidance with the Harpoon MVRS via small left thoracotomy. Patient selection was based on pre-intervention TEE, with suitability primarily based on a minimum 1.5:1 ratio of posterior prolapse segment length to anterior-posterior distance between the free edge of the anterior leaflet and the base of the prolapsed posterior segment. The primary endpoint was 30-day successful implantation of chords with MR reduction to moderate or less.

Results:

The primary endpoint was met in 27 of 30 patients (90 %); 3 patients required conversion to open mitral surgery. There were no deaths, strokes, or permanent pacemaker implantations. At 1 month, MR was mild or less in 24 of 27 patients (89%) and was moderate in 3 of 27 (11%). At 6 months, MR was mild or less in 22 of 26 patients (85%), moderate in 2 of 26 (8%), and severe in 2 of 26 (8%). Favorable cardiac remodeling at 6 months included decreases in end-diastolic volume (161 ± 36 to 122 ± 30 ml, p < 0.001) and left atrial volume (106 ± 36 to 69 ± 24 ml, p < 0.001). The anterior-posterior mitral annular dimension decreased from 34.7 ± 5.8 to 28.2 ± 5.1 mm (p < 0.001, and the mitral annular area decreased from 10.0 ± 2.7 to 6.9 ± 2.0 cm2 (p < 0.0001).

Conclusions:

The authors concluded that beating-heart ePTFE chordal implantation using the Harpoon MVRS can reduce the invasiveness and morbidity of conventional mitral valve surgery, that the safety profile of the device is promising, and that prospective trials comparing the outcomes of this device to conventional mitral valve repair surgery are warranted.

Perspective:

TAVR has reshaped the landscape for intervention among patients with severe, symptomatic aortic stenosis, and there is now extensive interest in transcatheter therapies for mitral valve repair or replacement. Beating-heart implantation of artificial chordae is one methodology for the attempted treatment of degenerative MR, with this device and another device currently in clinical trials. Probably pertinent only among patients with isolated, discrete (~ 1 cusp) posterior leaflet prolapse/flail, it will be of interest to see whether artificial chordal implantation without concomitant annuloplasty (long a mainstay of surgical repair of degenerative MR) will result in a durable mitral valve repair.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Aortic Surgery, Cardiac Surgery and VHD, Interventions and Imaging, Interventions and Structural Heart Disease, Echocardiography/Ultrasound, Mitral Regurgitation

Keywords: Aortic Valve Stenosis, Cardiac Surgical Procedures, Echocardiography, Transesophageal, Heart Valve Diseases, Mitral Valve Annuloplasty, Mitral Valve Insufficiency, Polytetrafluoroethylene, Prolapse, Thoracotomy, Transcatheter Aortic Valve Replacement


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