Medical Device Daily

PARIS – Though it's always fairly chancy to predict the next big thing in medical technology, doing so in the interventional sector of cardiology may not be too big a gamble.

Given the large and growing opportunity, potential patient demand and the rapid pace of technology development, that next big thing is likely to be percutaneous valve replacement and repair.

If the packed room of attendees Thursday at a session titled “Percutaneous aortic valve replacement” is any indicator, there is strong interest among clinicians in this technology. The session was supported by an educational grant from CoreValve (Paris), which appears to be making the most rapid clinical advances in aortic valve replacement, and a lineup of presenters reported on the company's progress in clinical trials.

The opportunity is undeniably huge, given, as in other areas of healthcare, the ballooning demographics of the elderly worldwide, together with the natural occurrence of valve defects, the growth in heart disease related to these factors, and the advancing ability of cardiology to do repairs of the heart with less-invasive approaches.

The path toward success in this area appears to have already been paved by companies such as NMT Medical (Boston) which are using their percutaneous technologies to close holes in the heart (linking this effort, for the most part, to the attempted decrease in associated migraine). And future versions of this percutaneous approach will be used to perform remodeling and reconstruction of the heart (internal cardio-lifts, you might say) to treat arrhythmias and other heart dysfunctions.

But in terms of both near-term and long-term opportunities, this path heads directly to valve repair and replacement.

Pieter Kappstein, MD, of Erasmus University (Rotterdam, the Netherlands) laid out some of the potential need. He cited figures estimating 300,000 valve procedures in 2003 and projections that this will grow 10 times more over the next 10 years. In terms of aortic valve replacement, he predicted up to 500,000 such procedures needed by 2050.

Just as chancy as predicting trends in med-tech is the ability to predict the outcome of open procedures to replace defective valves in high-risk patients. As those needing valve replacement grow older or have greater disease, they have less and less ability to withstand an open procedure or even be considered as “operable” though Kappstein warned against telling any cardiovascular surgeon that anyone is inoperable.

Hence, the initial and largest early opportunity for percutaneous valve replacement is in these high-risk patients who may not have any other choices for lengthened life.

In an article in the EuroPCR conference's daily publication (appropriately named Daily), Peter Block, MD, compared the use and initial applications of valve procedures to the early history of angioplasty.

“Remember,” he is quoted as saying, “angioplasty in the early days was a horrible procedure in retrospect, with 60% restenosis rates, yet still it moved forward thanks to patient demand.”

Thus, even with a risk/benefit ratio rather heavily weighted toward risk (even death), as compared to open surgical valve replacement and repair, the less invasive procedure will likely be driven, even demanded, by the need to avoid open surgery.

Block thus noted that the sector is in an important “transition period,” one that will be marked by a microscopic scrutiny of results taking into consideration the various endpoint benefits.

This, of course, means a variety of debates and decision-making difficulties concerning the choice between open procedures (biological or mechanical valves) and percutaneous approaches (single or multiple valve repair or replacement and which product to use) not only by patients and physicians but also by regulators.

Kappstein summarized by saying these choices will “not be easy,” and further complicated not only by potential co-morbidities but by the “background” effects of heart disease that are less observable and not accounted for in statistical endpoints.

Eberhard Grube of the Siegburg Heart Center (Siegburg, Germany) gave rapid review to a series of very small trials using CoreValve's Revalving system for aortic valve replacement – a porcine pericardial tissue valve fixed to a frame with PTFE sutures – consecutively with smaller profiles from 25 Fr down to 21 Fr, with the smaller profile providing better results and fewer complications.

The patients were drawn from the highest risk group in terms of age and the difficulty of withstanding the open procedure, providing the occasional expected adverse events, but none, he said related to device failure.

Also occasionally, the complications of disease blocked the procedure and forced transfer to surgery, but overall he said there was “no perioperative mortality” and that “all patients left the cath lab alive.”

He reported that in one trial 82% (28 patients) were discharged “alive and well” and 50% of those patients originally judged inoperable were discharged “alive and well.”

He predicted a device profile down to 18 Fr, thus allowing access through the shorter path of the popliteal artery rather than the femoral artery, hopefully leading to even better outcomes.

Grube reported three Generation-3 trials currently ongoing with the 18 Fr-profile system.

His conclusion: “Percutaneous implantation in high-risk patients is feasible. When successful, the procedure results in marked hemodynamic and clinical improvement. Up to nine months follow-up confirms sustained clinical benefit.”

Other presenters reported similar success in treating small groups of patients, with none of the adverse events, including one death, related to problems with the device itself.

The EuroPCR Daily also reported on successes using percutaneous pulmonary valve replacement and the repair of mitral valve regurgitation.

But the researchers clearly are following the careful path of reporting success without making overblown predictions of long-term outcomes.

Most candidly of all, Peter Block, MD, is quoted as calling any long-term prognostications “a bit of a crap shoot . . . nobody knows what will happen.” He referred to “promising results” in the early small trials but warned that the proof of the clinical pudding will be in larger randomized trials with long-term follow-up.

Carlos Ruiz, MD, a pioneer in the area of aortic valve replacement, noted that the technology is developing rapidly and that an annual meeting he has instituted on this area will be held next year in conjunction with EuroPCR which is slated for Barcelona next May.

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