The fledging techniques were the focus of several oral presentations during the TCT meeting. In one, Dr Ted Feldman (Northwestern University, Evanston, IL) presented an update on the Endovascular Valve Edge-to-Edge Repair Study (EVEREST) using the Evalve Clip (Evalve Inc, Redwood City, CA) device. So far, 27 patients out of a planned enrollment of 32 have received the percutaneous clip, designed to emulate the surgical edge-to-edge repair technique pioneered by Dr Ottavio Alfieri,in which the free edge of the anterior mitral valve leaflet is joined to the posterior leaflet, creating a point of permanent coaptation.

The primary end point of EVEREST is 30-day major adverse events, while a secondary objective of the trial is reduction in mitral regurgitation. So far, said Feldman, no deaths have occurred in the EVEREST participants, and the only adverse events have been one minor stroke and three clip detachments. In all cases, the clip remained attached to one of the valve leaflets and all patients were asymptomatic, the detachment being identified on protocol-driven echocardiography. More than two thirds of the patients achieved a reduction in mitral regurgitation of <2+ at the time of hospital discharge.

Importantly, Feldman noted, the clip procedure does not change the patients' surgical options. Indeed, he pointed out, the inclusion criteria for EVEREST require that patients be candidates for surgery, a key difference between the studies of endovascular mitral valve repair and percutaneous aortic valve replacement: the latter are currently enrolling only patients who are not eligible for surgery.

Plans are afoot for a phase 2 trial of the Evalve Clip and, while the FDA has yet to give its seal of approval, Feldman believes it will be a randomized comparison of the clip procedure with mitral repair surgery, with the type of repair at the surgeon's discretion.

Feldman emphasizes that the type of patient taking part in EVEREST is very different from the patients being enrolled in the pilot studies for valve replacement.

"The aortic-valve patient population includes patients who are very sick, and most of those procedures to date have been on patients who have had some instability during the procedure. The Evalve procedure is remarkably different. We had initially anticipated that manipulating catheters in the mitral valve in a beating heart would create a lot of hemodynamic instability, and we found very much the opposite, that these patients remain stable throughout the procedure. We have the great luxury of time to try to precisely place the clip, and we've had many instances where repositioning the clip a millimeter or two has made a great improvement in the control of the regurgitation, so we're very deliberate about where this is placed."

We're the first to acknowledge as cardiologists that the surgeons have been doing this for decades and know a whole lot more about what we're trying to do and what the results ought to look like.

Feldman is the first to acknowledge that close collaboration between surgeons and interventional cardiologists is essential to the ongoing development of this technique.

"Every center needs to have a cardiovascular surgeon as one of the investigators for this to work, for a variety of reasons," he explains. "One is that we need surgical standby in the event that we create some mishap. And the other element of this is that we're the first to acknowledge as cardiologists that the surgeons have been doing this for decades and know a whole lot more about what we're trying to do and what the results ought to look like."

As with other areas that have fallen under the purview of interventional cardiology, valve replacement is sometimes dubbed the new "turf war" between surgeons and interventional cardiologists. In a TCT debate, Dr Donald Baim (Brigham and Women's Hospital, Boston, MA) and Dr Michael Mack (Medical City Dallas Hospital, TX)squared off over whether the "predatory interventional cardiologist" would "conquer" valve replacement and repair.

Mack, slated to argue against the position that a takeover is an "inevitable consequence of technological progress," acknowledged at the outset that he had no delusions.

"I've been involved in a number of inflammatory debates here at the TCT over the years, and they do make for fun presentations, but I really don't view this as a contentious issue, despite the assigned topic that I have. As a matter of fact, the surgeons have been intimately involved with the invention and development of these devices....This is something that we do want to see going forward."

Baim, likewise, pointed out that interventional cardiologists "have this obsession with doing anything the surgeons can do open. We think we can do as well or better percutaneously." In the case of percutaneous valve replacement and repair, however, predation is the wrong metaphor. "This not a controversial issue," Baim stated. "It is inevitable that cardiologists are going to have a major role in valvular disease."

Many of the techniques being developed to treat these patients, he says, involve methods already within the "skill-set" of interventional cardiologists.

Already, he adds, "There are at least 150000 to 300000 patients per year who are either too sick for aortic valve replacement or not sick enough for mitral valve repair....We can enhance their quality of life substantially," Baim concluded.

When it was his turn, Mack observed that many surgeons may be looking at percutaneous valve pioneer Dr Alain Cribier (Charles Nicolle Hospital, Rouen, France)in much the same way they did the "father of angioplasty," Dr Andreas Gruentzig. "The response of the surgeon, naturally, is, Is this 1980 all over again? Is the same thing going to happen to valve disease that happened to coronary disease?"

Mack, however, agreed that the number of potential patients estimated by Baim is realistic. "There are huge cohorts of patients that never come across the surgical radar screen at the present time," Mack observed. These include patients with congestive heart failure or patients undergoing CABG who have only moderate mitral regurgitation.

Mack closed his talk mentioning a joint workshop sponsored by the Society of Cardiothoracic Surgeons that took place in April 2004 that brought together "all the major stakeholders"surgeons, interventional cardiologists, regulators, and industry, among othersto discuss future directions for percutaneous treatments for valve disease.

"It was much less contentious than anyone thought it would be," Mack said, adding that a consensus paper currently being "thrashed out" will likely be published by the end of the year.