The standard procedure for mitral valve repair requires open-heart surgery, performed under general anesthesia and using a heart-lung by-pass machine.  The access is through a median sternotomy or right thoracotomy, an incision is made in the left atrium of the heart, and the mitral valve is exposed.  The circulatory system of the patient is connected to a heart-lung by-pass machine that artificially oxygenates the blood. The cardio-thoracic surgeon repairs the valve with a number of methods which typically includes implanting an annuloplasty ring in the annulus of the valve.  Once the heart is closed and the patient is taken off the by-pass pump, the valve is assessed via ultrasound (echo) to determine the effectiveness of the repair.  The patient spends one or more days in an intensive care unit, where his/her heart function and general recovery are closely monitored.

Annuloplasty:

     Annuloplasty refers to the process of repairing the fibrous tissue where the mitral valve leaflets attach to the walls of left atrium (the annulus). Certain diseases such as ischemic mitral regurgitation (IMR) cause the ventricle to enlarge, which in turn causes the annulus to dilate.  This annular dilatation needs to be corrected in order to restore competence to the mitral valve.  To repair the diseased valve, a surgeon implants an annuloplasty ring at the annulus of the valve to restore the natural shape.

    Proper ring sizing is critical to correcting the MR. If the annuloplasty ring is undersized, the valve effective orifice area (EOA) may to too small for adequate flow and/or cause systolic anterior motion (SAM) of the anterior leaflet, where the LV outflow tract is compromised.  If the ring is too large, the annulus shape will not be adequately adjusted, and the MR will not be corrected. 

Efficacy of the Surgical Treatment:

     In mitral valve repair, there are primarily two issues in a long term effective repair; sub-optimal leaflet coaptation and late recurring MR.   In the sub-optimal leaflet coaptation situation, the repair of the patient’s mitral valve results in a normal annulus geometry a suboptimal leaflet coaptation length, height or location.  It is difficult for the surgeon to assess the completeness of the repair/annuloplasty, until the patient is removed from the by-pass pump. If there is residual MR  (NYHA classification 2+ or greater ), the patient will require a second by-pass pump run and surgical correction.  When the echo assessment indicates residual MR is < 2 grade with acceptable leaflet coaptation, the patient is typically sent to intensive care and subsequently discharged.  If the leaflet coaptation is suboptimal and causes SAM, a secondary correction is necessary. The MiCardia dynamic annuloplasty ring is designed to address suboptimal leaflet coaptation by allowing for real-time echo guided annulus reshaping.

    MiCardia addresses recurring MR through annulus reshaping via catheter based technology.  In Ischemic MR, 10-30% of the patients undergoing mitral valve repair return with MR in the first twelve months post surgery.  This recurring patient population is typically either untreatable or treated with medical therapy.  If a MiCardia dynamic annuloplasty ring is implanted during the initial surgical repair, it can be “reshaped” minimally invasively using interventional techniques to treat the recurring MR.  The activation method will involve accessing the implanted ring via a percutaneous femoral vein introduction and applying energy to the ring. The procedure is completed under fluoroscopic and echo guidance.