Procedures & Innovations Valve Repair & Replacement

Edge-To-Edge Mitral Valve Repair: The "Bow-Tie Procedure"

Mitral valve regurgitation (MR), most commonly caused by mitral valve prolapse, affects approximately 6% of women and 3% of men. However, after the age of 55, some degree of MR is found in almost 20% of men and women who undergo echocardiograms. Traditional surgical treatments to restore mitral valve function are highly invasive and often ineffective. At Columbia University Medical Center, Mehmet Oz, MD has advanced a mitral valve repair technique known as the "bow-tie" procedure by using minimally invasive approach and a specialized grasping tool.

Dr. Oz's work is based on an earlier study performed by Ottavio Alfieri, MD at the San Raffaele Hospital in Milan, Italy which was published in the October 2001 issue of The Journal of Thoracic and Cardiovascular Surgery. In Alfieri's approach, a double-orifice mitral valve is created by approximating the free edges of the leaflets at the site of MR. The operation is performed through a sternotomy during cardiopulmonary bypass. The mitral valve is approached through the left atrium, with the incision done in the interatrial groove.

The original study done on the efficacy of this procedure by Alfieri in 1995 observed 260 patients over 7 years. He demonstrated a 94.4% 5-year survival rate, with freedom from reoperation of 90.0%. Since this study was performed, researchers at Columbia have worked to improve these results by allowing for a minimally invasive technique that would eliminate the need for open-heart surgery in patients with MR.

The Bow-tie Experience at Columbia

The ongoing Bow-tie study at Columbia which started in the fall of 1997 has 71 enrolled patients as of the summer or 2003. The preliminary results of this study boast a 0% rupture rate in the bow-tie suture and less than 6% of patients having to undergo mitral valve reoperation. Mitral regurgitation decreased from a mean value of 3.6 to .8 (p<.0001) with an increase in ejection fraction from 33% to 45%. Mitral valve area decreased from 2.5 to 2.1 after surgery, but increased during exercise, further supporting the concept that this technique maintains mitral valve annular function.

At Columbia, 51.8% of patients had annuloplasty ring placement in addition to mitral valve repair by the bow-tie stitch, but had similar survival rates to those repaired with the stitch alone (p=.77). Thus, this procedure is now accepted as a valuable addition to the surgical options available to treat mitral insufficiency or as an adjunct to standard repair techniques that fail to achieve acceptable results.

Future Goals

Because the bow-tie procedure still requires cardiopulmonary bypass, research is underway in experimenting with a catheter approach which mirrors the concept of the bow-tie procedure but is minimally invasive. This new technique, known as the endovascular valve technique or evalve, shows promising results in initial clinical trials.