Transcatheter Treatment of Mitral Valve Disease: Déjà Vu All Over Again?

Abstract

Article, see p 189 The catheter-based treatment of aortic valve disease has significantly transformed the management of patients with aortic stenosis (AS) over the past decade. Transcatheter aortic valve replacement (TAVR) has now become firmly established as a mainstay in the treatment of patients with severe AS. TAVR has been demonstrated to be superior to medical therapy in surgically inoperable patients with AS and equivalent to surgery in patients deemed at high and intermediate risk for surgical aortic valve replacement.1–3 With randomized trials comparing TAVR with surgical aortic valve replacement in low-surgical-risk patients now underway in the United States, it is not too much of a stretch to believe that TAVR will become the predominant strategy in the treatment of AS in the second decade after clinical introduction. With that context in mind, is it likely that we will see the same transformative success with catheter-based approaches for the treatment of mitral valve disease? To assess the potential role of transcatheter therapies in the treatment of patients with severe mitral regurgitation (MR), it is necessary to first divide MR into 2 broad categories, primary (or degenerative) and secondary (or functional) MR. Primary MR is a disease of the valve itself and ranges across the spectrum from fibroelastic deficiency causing isolated prolapse of the posterior leaflet to Barlow disease in which there is an excess of mitral tissue and complex repair techniques are necessary.4 Secondary MR is a disease of the left ventricle, not of the mitral valve. MR is caused by apical and lateral distraction of the papillary muscles as the ventricle dilates, which causes tethering and lack of leaflet coaptation. It is a dynamic condition: The more dilated the left ventricle is and the greater the tethering is, the more severe the MR is.5 …