Transcatheter Mitral Valve Repair for Treating Mitral Regurgitation

MR is a cardiac valve disease that typically occurs slowly without symptoms as progressive damage to the mitral valve prevents the mitral leaflets from closing properly.1 The mitral valve is located between the heart's left atrial (upper) and left ventricular (lower) chambers. Poorly functioning leaflets allow blood to flow backward between the chambers as the heart pumps.1 Advanced MR may require surgical repair or replacement of the diseased mitral valve.2,3 Left untreated, severe MR can lead to congestive heart failure or serious cardiac arrhythmias.1

Many patients with MR may be poor surgical candidates due to age and/or comorbid disease. Manufacturers have been developing minimally invasive transcatheter approaches (performed through a catheter) that may offer alternatives to open surgery for mitral valve repair for patients who are ineligible for surgery or at very high risk of complications from surgery. Two transcatheter approaches are in development that target mitral valves: the MitraClip procedure and percutaneous annuloplasty procedure using the Carillon Mitral Contour System.

The MitraClip delivery system is intended to replicate the functional effects achieved by the Alfieri edge-to-edge surgical technique.4-7 In the Alfieri procedure, a surgeon sutures the edges of two opposing mitral valve leaflets at the center of the valve opening, leaving two smaller openings on either side that close more completely than a single large opening.8 The MitraClip procedure replaces the sutures with a two-armed, flexible metal clip covered in polyester fabric.9 The MitraClip system consists of a steerable guide catheter, including a clip delivery device, and the MitraClip implant.5

To implant the MitraClip, a physician inserts the guide catheter into the femoral vein at the groin and threads it up to the heart into the right atrium under fluoroscopic guidance in a cardiac catheterization lab.5,9 To reach the mitral valve in the left atrium, the physician performs a transseptal puncture to create an opening in the septum—the wall that separates the right and left atrial chambers—with the needlelike dilator within the catheter.4,10 (Use of transseptal atrial puncture has traditionally been limited to large interventional cardiac care programs staffed with electrophysiologists who are well-experienced in the technique.11) Then the operator advances the catheter into the left atrium and through the mitral valve as the clip is expanded. Using Doppler ultrasound to assess the optimal clip placement to correct valve leaks, the physician grasps and fastens the edges of the valve leaflets together with the MitraClip.4,10 Before releasing the implant from the clip delivery device for permanent placement, the physician confirms proper positioning of the MitraClip with further ultrasound scans. If the device positioning is acceptable, the physician releases the clip from the delivery device and removes the catheter.4,12 The MitraClip device will most likely be used for patients...