Mitral regurgitation (MR) is one of the most common valvular abnormalities. Medical management along with regular surveillance is the recommendation for mild MR. Traditionally, management of severe disease has been surgical intervention More recently, studies have proven that the transcatheter approach is falling in favor. The edge-to-edge leaflet repair device is a minimally invasive catheter-based therapy that uses a clip to bring together the tow flailing leaflets which results in decreased or resolution of regurgitation. This chapter will discuss in detail primary and secondary mitral regurgitation, non-invasive catheter management options including indications, contraindication, procedural technique, and complications.
The mitral valve (MV) apparatus is an anatomically complex structure that includes the ventricle, papillary muscles, chordae tendineae, leaflets, and the mitral annulus. Alteration to any of these can lead to the development of mitral regurgitation (MR). Mitral regurgitation is when the valve does not close completely, which allows for backward blood flow leading to a number of different problems. The two types of MR are primary or secondary. Primary mitral regurgitation is degenerative valve disease, while secondary mitral valve regurgitation is characterized as functional myocardial disease. MR is further classified further as mild, moderate, and severe. Severe (or moderate-severe) MR is currently only recommended for catheter management. Echocardiogram is the primary tool used to assess the severity of MR. Severe MR is described as having a color flow jet that may be central and large (>6 cm or >30 percent of left atrial area) or smaller if eccentric, encircling the left atrium. Pulmonary vein flow may show systolic blunting or systolic flow reversal, vena contracta width =0.5 cm measured in the parasternal long axis view, a regurgitant volume of =45 mL/beat, regurgitant fraction =40 percent, and/or regurgitant orifice area =0.30 cm^2 according to the American College of Cardiology and American Heart Association.  Several interventions exist to treat severe MR including surgical and non-surgical. If left untreated severe MR can lead to fatal sequelae including heart failure.
Currently, the edge-to-edge leaflet repair device is the only recommended intervention to treat MR are limited, but there are many emerging technologies including but not limited to neo-cords, transcatheter mitral valve repair, and rings. At present, the following are the indications for this device:
The edge-to-edge leaflet repair device procedure is a relatively straightforward procedure requiring only a few specific pieces of equipment listed below:
The key personnel required to adequately and safely perform catheter-based MR treatment with the edge-to-edge leaflet repair device:
Before undergoing a catheter-based approach to MR management requires a particular assessment of the mitral valve apparatus by echocardiogram and sometimes other forms of cardiac imaging by a trained cardiovascular interventionalist. Sometimes a cardiovascular imaging specialist is used for the consult. The principal preparation for any procedure is to obtain a sterile field. As in most catheterizations, the site of sterilization is the site of catheter insertion. All personnel close to the sterile field should scrub and fully gowned. Clean and drape the area before beginning the procedure.
The edge-to-edge leaflet repair device
The transcatheter mitral valve repair with the edge-to-edge leaflet repair device is performed a laboratory specialized for cardiac catheterization. It uses a mix of fluoroscopic and transesophageal echocardiographic (TEE) guidance to image the heart before, during, and after the procedure. The patient is placed under general anesthesia to ease, comfort, and reduce movement during the procedure. The procedure begins with gaining access. The femoral vein is the preferred area of entry. A transseptal puncture is performed to cross the interatrial septum into the left atrium (LA). The edge-to-edge leaflet repair device catheter, which is manipulable within the vasculature, is then advanced into the LA. Echocardiographic guidance instrumentation is used to position the catheter device in the correct place. The edge-to-edge leaflet repair device is then pulled back on with the clip limbs open to attach to the leaflets at the site of insufficiency. The limbs are then closed, and then a repeat Doppler echocardiography is performed to evaluate the results of the treated MR. If the MR has not reduced adequately to the surgeon's satisfaction, then the device can be repositioned . Once the clip positioning is satisfactory, catheter removal from the access site follows and closure ensues with pressure. The patient is then monitored for 4-6 hours post-op to check for any complications.
The edge-to-edge leaflet repair device has many possible complications to include but not be limited to the following:
Catheter management of mitral regurgitations is a relatively recent innovation. At the risk of an understatement, it is a considerable advancement in the world of cardiology. It allows for those with severe MR who are nonsurgical candidates to now have an option for mitral valve correction. Recently studies have shown catheter management to be superior to surgical intervention in some circumstances.
Catheter management of mitral valve regurgitation is a serious procedure and can carry some serious potential complications. Fortunately, most complications are rare, but the procedure should be taken seriously and performed by a highly trained cardiovascular interventionalist [level 1]. In addition to a highly trained physician, it is important to have a team approach when assessing these patients. Before the intervention, the following should take place: