Transcatheter mitral valve replacement reboots

We had a phase of several years when the mitral valve programs were working hard to figure out how to get started. There has been a sort of critical mass of learning that has now launched the field, with reports on clinical use of three different systems coming out this year.

The procedural understanding that developed during a decade of work on transcatheter aortic valve replacement has helped us figure out how to do mitral valves by generating a broad base of technique development, for example, an understanding of how to percutaneously deliver prosthetic devices more coaxially. It sounds simple, but it had been a critical obstacle for treating the mitral valve.

Dr. Ted Feldman

Other technical challenges of transcatheter mitral valve replacement have been designing replacement valves to fit the noncircular mitral orifice, and the absence of calcium deposits on the mitral valve to help anchor a prosthesis. There has also been improving understanding of patient selection, including which patients are best suited to transcatheter mitral valve replacement and when is the best time in the course of mitral valve disease to intervene.

Although the safety and efficacy of the mitral clip as a transcatheter approach to mitral valve repair are now established, at least half and perhaps as many as three-quarters of patients with severe mitral regurgitation are not good candidates for clip repair. This includes patients with commissural mitral regurgitation because clip placement in corners can be difficult, patients with large jet origins that can be too big to grab with a clip, and patients with calcified mitral valve leaflets that can’t be clipped, so there are plenty of patients for whom transcatheter valve replacement would be better than clipping.

D. Ted Feldman, M.D., is director of cardiac catheterization at North Shore University Health System in Evanston, Ill. He was lead investigator for the EVEREST II trial that established the safety and efficacy of the mitral clip (N. Engl. J. Med 2011;364:1395-1406). He has been a consultant to Abbott Vascular, Boston Scientific, Edwards, and Jenavalve. He made these comments in an interview.