Saturday, May 13, 2006

Clip and Tuck for your Leaky Mitral Valve

If you're a heart patient with a leaky mitral valve, you might have heard about this trial, EVEREST II, reported today that uses a small clip manufactured by Evalve, Inc. to repair the leak. Our own Ted Feldman, MD is the principle investigator on this trial. It's important to realize the selection criteria for this trial is very limited, but if you're quite symptomatic AND have the right anatomy, this might be a great way to avoid open heart surgery.

So what is the mitral valve? It's the valve that is the "intake" heart valve of the main pumping chamber of your heart (the left ventricle). If it's blocked, blood has a hard time entering this main pumping chamber. If the mitral valve leaks, or "regurgitates", blood passes backward during the pumping action of the left ventricle, to push blood backward into the lungs, making people short of breath, especially when they exert themselves.

This new Evalve system seeks to correct an excessively leaky mitral valve by placing a small clip on the two leaflets of the mitral valve and effectively "tucking" them together, making two smaller openings of the mitral valve from its one large opening. While this decreases the forward flow a bit, it can (in the correctly chosen cases) minimize the backward flow of blood to the lungs dramatically.

What I've been impressed with is that these cases require tremendous patience and operator skill. The procedure is performed using both xray and ultrasound guidance (using a transesophageal echo probe inserted in the esophagus or swallowing tube). Yes, you are asleep during this procedure. The physician then passes a sophisticated apparatus from a vein in the legs through the wall between the upper chambers of the heart to access the left atrium just above the mitral valve. It is from this vantage point that the physician literally must grab each of the mitral valve leaflets as they move and securely place this clip on each leaflet of the mitral valve. Wrong placement might lead the device to dislodge and the person need surgery to repair the valve. It is this technical challenge that requires the right type of leaky mitral valve to assure success. Since we started this procedure at our institution, there have been steady improvements in the design of the device, but enrollment has been very careful and slow because of the selection process employed.

Cool stuff. Just not quite ready for the majority of leaky mitral valves.... yet.


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