In some patients with defective valvular function, it is desirable to repair the valve rather than perform a more aggressive replacement procedure. Valvuloplasty can be employed on a stenotic valve (one that no longer opens fully) in an attempt to break adhesions or other structural causes, to once again allow for greater valve opening and improved blood flow. To date, it is most common to replace a defective valve with either a mechanical (requiring anti-coagulation therapy) or tissue valve. More recently, there is growing availability of replacement cardiac valves that can be delivered without the need for open-heart surgery; rather, valves are delivered to the heart via a catheter (transcatheter delivered valves). Many of the patients receiving this therapy are not candidates for open-heart procedures. Today, such technologies have been used clinically to treat pulmonic and aortic valvular disease.
More specifically, mitral valve dysfunction can be related to several factors including diseased leaflets, annular changes, abnormal or damaged chordae, and ventricular dilatation causing displacement of the papillary muscles. Due to the large variability in disease process, a wide variety of transcatheter devices are being investigated for the mitral valve. These transcatheter devices can be subdivided into five general types:
- devices for Alfieri-type edge-to-edge repair;
- indirect annuloplasty devices deployed into the coronary sinus;
- direct annuloplasty devices placed on or near the mitral annulus;
- devices for dimensional control of the left ventricle or left atrium;
- devices for mitral valve replacement.