Heartfelt with Dr Melissa Walton-ShirleyView all posts »
EVEREST II mitral-valve clip: It's a good start but still a long way to the topMar 15, 2010 11:30 EDT
Cardiologist/Sherpa Dr Ted Feldman (Evanston Hospital, IL) presented the EVEREST II data, a study comparing a percutaneous approach to standard surgical repair for mitral-valve leak. EVEREST is a fitting title for this study, as the 29 035 ft (that's 8850 m for all you metric folks) summit is the highest mountain on earth and considered one of the most challenging peaks in the history of mountain climbing. Similarly, the challenges of the timing of therapy, selection of treatment options, and reliability of quantification of mitral regurgitation are legendary.
In order to truly understand the impact of this study, we need to level the playing field a bit. First, I want to take nothing from the study and all of those who participated. Although some might not want to acknowledge it, this is one of the single most important advances in the field of mitral-valve pathology since surgical repair. However, it's so early in its development it's quite like a phase 2 trial that's still trying to find its legs. The current technique provides only a small glimpse of just how large this field of percutaneous valvular therapy will become. I want to state for the record that including transfusion in the 30-day MACE rate to make the surgical therapy appear far more "dangerous" was playing a little bit of dirty pool. I want to point out that after transfusion and the need for a ventilator for 48 hours is taken out of the MACE rate, mitral-valve surgery is still a relatively safe and far more efficacious approach to the therapy of significant mitral regurgitation when purely looking at the postprocedure volume of the regurgitant jet.
The residual mitral regurgitation is the most disappointing aspect of this small trial. With a short 30-day and one-year follow up, I fear those patients will continue to be stable for only a short while, as many patients with moderate to severe mitral regurgitation will begin to deteriorate once again with debilitating dyspnea. What exactly do we think will keep the ventricle from continuing to increase in size and ultimately fail in these patients? Are we just putting off the inevitable? For some patients at advanced age, where quality becomes far more important than quantity, this procedure will be just the thing they are looking for. The perfect patients will be those whose risk will be considered too great for surgery and their life expectancy too short to worry about long-term results.
Then, as pointed out by Dr Craig Smith (Columbia University, NY), who commented to heartwire, there is the worrisome possibility that the patient with a single percutaneous repair under his belt will be taking home some metal instead of undergoing a native valve repair in the future. Once you've gone in with a clip, fused the edges together, and started the process of scarring, you have probably wrecked any hope for a repair opportunity. On the other hand, by that time, we might as well accept it's just time for a new valve and do it.
Like a long and treacherous climb, not everyone will be able to make it to the top of the mountain. Some can't even begin the journey, and for those who do, there are dangers and advantages to every choice that is made along the way. With regard to percutaneous mitral-valve repair, the adventure is just beginning.
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