Medical Device Daily Contributing Writer
LAS VEGAS — The fifth annual Vascular Interventional Advances (VIVA) meeting took place here last week, with that gathering seeking to integrate all four specialties involved in the care of patients with vascular disease: vascular surgery, interventional cardiology, vascular medicine, and interventional radiology. One of the key areas of focus of this meeting, as at previous ones, is peripheral vascular disease (PVD), also called peripheral arterial disease (PAD). There is little question that PVD represents an enormous market opportunity with a plethora of unsolved clinical issues.
PAD is a progressive disease that affects 11 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. It is clear that the public’s knowledge of PAD, as thus its consequences, is poor.
As evidence, a recent telephone survey of 2,501 adults over age 50, conducted by the PAD Coalition (Lakewood, Colorado), found respondents’ awareness of PAD at just 25%, markedly lower than for stroke (74%), coronary artery disease (67%) and heart failure (67 %). Yet, the risk for PAD is equal to or greater than the risk for these conditions.
Interestingly, survey respondents were much more aware of relatively rare diseases that affect far fewer people, including Lou Gehrig’s Disease (36%), multiple sclerosis (42%) and cystic fibrosis (29%). These results were reported in an article, “Gaps in Public Knowledge of Peripheral Arterial Disease. The First National PAD Public Awareness Survey,” in the Sept. 18, 2007, issue of the journal of the American Heart Association (Dallas, Texas), Circulation.
Hoping to change this situation, the U.S. Senate recently passed a resolution declaring September “PAD Awareness Month.” About 500,000 to 600,000 interventional procedures are performed annually in the U.S. In addition, some 150,000 to 160,000 leg bypass surgeries and an additional 150,000 to 175,000 leg amputations are performed annually.
These latter two surgeries are typically directly related to the presence of PAD. A variety of interventional tools have been used to treat PAD, some (for instance, balloon angioplasty or PTA) have been commercially available for many years, while others (such as, cryoplasty) are relative new.
In addition to the sorry lack of awareness, there is a clear need for better technology and improved clinical outcomes, a point emphasized at the VIVA meeting.
At a lunch-time symposium titled “Stenting in the Superficial Femoral Artery: Going to Great Lengths on Clinical Studies” sponsored by ev3 (Plymouth, Minnesota), 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 low 33%.
At an evening satellite symposium titled “Management of Peripheral Arterial Disease: Challenges and Conquests,” sponsored by one of the PAD industry leaders Spectranetics (Colorado Springs, Colorado) moderator Michael Jaff, DO, instructor in medicine, Harvard Medical School (Cambridge, Massachusetts), called this data “dismal and very disappointing.” In another talk later in the conference, Rocha-Singh again presented the data, noting that the Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) group had supported the use of peripheral balloon angioplasty in its recommendations, saying that “the low morbidity and mortality of endovascular techniques such as PTA makes it the preferred choice of therapy ... for stenosis up to 10 cms. in length.”
This recommendation was published in the January 2007 issue of the Journal of Vascular Surgery. But Rocha-Singh said, “I question this recommendation,” adding: “PTA is viable for short lesions of 4 [cm] to 6 cm and not for longer ones.” The VIVA group and the medical device industry are striving to improve the situation.
For example, ev3 has embarked on a series of clinical trials for its Everflex peripheral stent.
Two key trials are the DURABILITY 1 trial in Europe, which has enrolled over 150 patients at 13 sites and the DURABILITY 2 trial, which will enroll nearly 300 patients at 30 sites in the U.S. The goal of these two trials is to demonstrate that a very long stent can be safe (meaning, low fracture and re-stenosis rate) and effective in the superficial femoral artery (SFA).
Rocha-Singh referred to the “extreme challenges of the SFA” due to its length, its tortuosity and its position running through a joint (knee) that is regularly flexed. In addition to better clinical trials, better devices are being developed that could improve the treatment of peripheral vascular disease.
For example, privately-owned Pathway Medical Technologies (Kirkland, Washington) has developed the Pathway PV Atherectomy system, which the company believes can treat the entire spectrum of disease found in the PAD patient.
Its system has expandable, very rapidly rotating scraping blades with dynamic aspiration for preemptive removal of both hard and soft plaque. The company has treated 172 patients in Europe, about two-thirds in the SFA and used this data to file a 510(k) application with the FDA in August 2007. It hopes for approval in Q1-08 and has already begun hiring a direct sales force in the U.S.
CEO Tom Clement told MDD that he expects that the ease of use, predictability and applicability of its device for both hard and soft lesions will enable it to take market share away from both PTA and stents, which he said account for about 80% of the PAD intervention market.
Another newcomer to the PAD market is Cardiovascular Systems (CSI; St. Paul, Minnesota) which has developed the Diamondback 360° Orbital Atherectomy System.
(See adjacent story for more on the device, which just received FDA 510(k) clearance.)
At an evening symposium sponsored by CSI, Dan Dulas, MD, interventional cardiologist from Mercy Medical Center (Minneapolis) reported on the company’s pivotal OASIS trial, noting that it exceeded all the FDA-required benchmarks for approval.