Percutaneous mitral valve repair in recurrent severe mitral valve regurgitation after mitral annuloplasty : MitraClip-in-the-ring as a complementary strategy

Radiofrequency ablation alters the microstructural organization of healthy and enzymatically digested porcine mitral valves

BACKGROUND

Myxomatous mitral valve degeneration is a common cause of mitral regurgitation and is often associated with mitral valve prolapse. With no known targets to pharmacologically treat mitral valve prolapse, surgery is often the only treatment option. Recently, radiofrequency ablation has been proposed as a percutaneous alternative to surgical resection for the reduction of mitral valve leaflet area.

OBJECTIVE

Using an in vitro model of porcine mitral valve anterior leaflet enlargement following enzymatic digestion, we sought to investigate mechanisms by which radiofrequency ablation alters the geometry, microstructural organization, and mechanical properties of healthy and digested leaflets.

METHODS

Paired measurements before and after ablation revealed the impact of radiofrequency ablation on leaflet properties. Multiphoton imaging was used to characterize changes in the structure and organization of the valvular extracellular matrix; planar biaxial mechanical testing and constitutive modeling were used to estimate mechanical properties of healthy and digested leaflets.

RESULTS

Enzymatic digestion increased leaflet area and thickness to a similar extent as clinical mitral valve disease. Radiofrequency ablation altered extracellular matrix alignment and reduced the area of digested leaflets to that of control. Additionally, enzymatic digestion resulted in fiber alignment and reorientation toward the radial direction, causing increased forces during ablation and a structural stiffening which was improved by radiofrequency ablation.

CONCLUSION

Radiofrequency ablation induces radial extracellular matrix alignment and effectively reduces the area of enlarged mitral valve leaflets. Hence, this technique may be a therapeutic approach for myxomatous mitral valve disease and is thus an avenue for future study.

Long-term results of the edge-to-edge repair for failed mitral valve repair as a bailout option

OBJECTIVE

We evaluate the long-term clinical and echocardiographic outcomes of edge-to-edge (E2E) repair combined with mitral annuloplasty in our institute with degenerative mitral regurgitation (MR) up to 10 years.

METHODS

Twenty-six consecutive patients undergoing E2E mitral repair after failure of other conventional mitral repair technique. There were 16 (61.5%) male and the mean age was 52.2 ± 10.4 years. Mitral regurgitation was due to anterior leaflet prolapse in 12 (46.2%) patients, bileaflet prolapse in 9 (34.6%), and multiple segment posterior leaflet prolapse in 5 (19.2%).

RESULTS

There were no perioperative deaths. Follow-up was 100% complete. The mean length of follow-up was 8.7 ± 0.9 years (median 8.4 years, 6.8-10.1 years). Two patients required reoperation of the MV. The freedom from reoperation and ≥ Moderate MR at 10 years was 69.9 ± 11.7%. The freedom from reoperation, ≥ Moderate MR and mitral stenosis (MS) at 10 years was (59.6 ± 10.0) %. The mean transmitral pressure gradient (TMPG) was 6.1 ± 2.5 mmHg, which was significantly elevated compared with preoperative TTE (P = 0.004). The freedom from ≥ Moderate MS at 10 years was 76.9 ± 8.3%. There were no differences between patients with and without MS at follow-up regarding the echocardiographic parameters and clinical status.

CONCLUSION

There is a slowly progressive elevation of TMPG after E2E mitral repair, while mildly elevated TMPG can be tolerated in most patients. In appropriate patients, the E2E repair combined with annuloplasty provides an effective "bailout" choice.