Medical Device Daily Contributing Writer
LAS VEGAS — The sixth annual Vascular Interventional Advances (VIVA) meeting, which describes itself as "the national education course for vascular intervention and medicine," took place here last week. Record attendance was fueled by an outstanding program, an excellent new venue at the Wynn Resort and the increasing recognition that peripheral arterial disease (PAD) represents an enormous market opportunity with a plethora of unsolved clinical issues.
PAD is a progressive disease that affects 11 million to 12 million people in the U.S., and with the aging of the population and the pandemic of obesity-induced diabetes, the incidence is growing rapidly. Within that group of patients, somewhere between 1 million and 3 million suffer from debilitating leg claudication (disability of walking due to crippling of the legs), which causes pain, reduced mobility and in many cases, depression.
Among the important "takeaways" from the VIVA conference is that while the interventional tools to treat PAD have improved significantly in recent years, there is a need for further innovation. The current set of tools—which include stents, balloons, atherectomy devices such as lasers and rotational "gizmos," thrombolysis, drugs and bypass grafts — often are not successful on a stand-alone basis and typically several devices are required to recanalize the artery.
The availability and use of multiple devices gives rise to two problems. First, which device should be employed and second, the high cost of employing "poly-therapy."
The latter topic was tackled by numerous speakers, including Mahmood Razavi, MD, an interventional radiologist from St. Joseph Vascular Institute (Orange, Califoirnia), whose topic was "Choosing Atherectomy: Which Device and What Data?" He rhetorically asked his audience "are all these costly interventions justified by their clinical outcome" and then quickly answered his own question, quipping "dunno."
Another speaker, Joshua Beckmann, MD, a director of the cardiovascular fellowship training program at Brigham and Women's Hospital (Boston), appealed to the audience, saying, "We need more data, not just opinions, to justify the high cost of these procedures."
The lack of solid clinical data (i.e., randomized clinical trials) and widespread off-label use (notably for biliary stents) may jeopardize reimbursement. According to Michael Jaff, DO, medical director of the Vascular Diagnostic Laboratory at Massachusetts General Hospital (also Boston), "continued reimbursement for peripheral arterial intervention is going to come up for review by CMS [Centers for Medicare & Medicaid Services]."
And, often when data is available, it is mediocre at best. For example, at last year's VIVA meeting, Krishna Rocha-Singh, MD, clinical assistant professor of medicine at Southern Illinois University School of Medicine (Springfield, Illinois), reported on a meta-analysis of five European randomized peripheral balloon angioplasty trials and combined this with data with the trial data from three U.S. companies. The net result was that at one year the patency rate was a surprisingly –indeed, appallingly — low 33%.
Atherectomy is a key modality for treating PAD, and according to a recent investor presentation by PAD market leader ev3 (Plymouth, Minnesota), atherectomy accounted for about 19% of the minimally invasive PAD device market in 2007. Medical Device Daily estimates that there were 60,000 to 70,000 atherectomy procedures performed last year in the U.S.
At last year's VIVA, privately-owned Cardiovascular Systems (St. Paul, Minnesota) made its debut with much fanfare. Since its launch about one year ago, the CSI Diamondback 360° Orbital Atherectomy System has enjoyed tremendous growth, fueled primarily by an aggressive sales effort and strong physician support. Although the company does not publicly disclose its sales figures, several knowledgeable sources have "whispered" that it is running now at a $40 to $50 million annual rate.
The next potential success story in atherectomy may be privately-owned, venture capital-backed Pathway Medical Technologies (Kirkland, Washington), which in early September received FDA 510(k) clearance to market its Jetstream catheter for PAD. This approval was based on the results of its successful multi-center pivotal trial of 172 patients conducted at nine centers in Europe.
Its system has expandable, very rapidly rotating scraping blades with dynamic aspiration for preemptive removal of both hard and soft plaque, as well as calcium, thrombus and fibrotic lesions. This broad applicability and its ease of use should enable Pathway to compete in all segments of the atherectomy market.
According to William Gray, MD, chairman of the Pathway scientific advisory board and director of endovascular services in the Center for Interventional Vascular Therapy at New York-Presbyterian Hospital (New York), "Clinical data suggests that Jetstream is quite effective at debulking and treating vascular disease in the peripheral vasculature. I have seen the efficacy of the Pathway technology first-hand in several cases in Germany and look forward to treating future atherectomy candidates."
Pathway has hired its first 20 sales reps for the U.S. market and is in the midst of a full scale market launch. Founder Tom Clement, in an interview with MDD, indicated that he felt that his company's product is a "game changer" and should quickly garner significant market atherectomy share, as well as growing the underserved PAD market.
Its leadership team has been bolstered by the naming of Paul Buckman, a seasoned and well-respected medical executive, as chairman of the board.
The treatment of chronic total occlusion (CTO) remains a significant challenge in both peripheral and coronary vessels. Because of its complexity and relatively poor results, it has been referred to by many clinicians as the "last frontier" of vascular intervention. It was a major focus at VIVA, with a session on the first day of the conference titled, "Advanced Endovascular CTO Tutorial" kicking things off.
Numerous CTO technologies have been developed over the years and they have not enjoyed particularly strong market acceptance, mainly because their clinical success has been mediocre. As a result, the overall domestic peripheral CTO device crossing market is estimated in 2008 at a modest $50 million.
Privately owned, venture capital-backed Flowcardia (Sunnyvale, California) is the most recent entrant, with FDA 510(k) clearance for PAD received in December 2007. Its Crosser catheter uses high-frequency mechanical vibration, which acts like a jackhammer to unblock the vessel and allow for subsequent angioplasty or other device follow-up.
At a company-sponsored luncheon, James Joye, DO, an interventional cardiologist from El Camino Hospital (Mountain View, California), discussed the results of the 85 patient multi-center Peripheral Approach To Recanalization In Occluded Totals (PATRIOT) trial.
Joye indicated that the primary efficacy endpoint, advancement of the catheter into or through the total occlusions, was achieved 84% of the time. This is a strong affirmation of its efficacy, particularly considering that many of these lesions were very long and heavily calcified and the patients had several co-morbidities.
He also noted that the primary safety endpoint, freedom from clinical perforation, was also handily achieved. Summarizing the data, Joye said that "this is a tough group of patients who fared very well."
Gray, another presenter who has significant experience with the device, was equally upbeat, saying that "it really makes a difference to patients who are suffering from excruciating leg pain." He added that "the Crosser provides us with an excellent option to treat peripheral CTOs, which are complex and challenging."
The last presenter, Jihad Mustapha, MD, an interventional cardiologist from Spectrum Butterworth Health (Grand Rapids, Michigan), reviewed several of his CTO cases and enthusiastically endorsed the Crosser. In response to a question about why there are any procedural failures, Mustapha said it is mainly due to the "lack of patience and improper catheter placement. If a clinician will take the time, this device will work nearly all the time."