MIAMI BEACH – Devices for endovascular repair of abdominal aortic aneurysms are evolving, with new sizing or other innovations either recently on the market or in studies.
The new products expand the scope of patients who are candidates for endovascular aneurysm repair (EVAR), and in one case bring a new approach to EVAR into the clinic.
During a session at ISET 2012, an international symposium on endovascular therapy, seven experts gave the following quick updates on what’s new in EVAR for 2012:
• Making devices smaller. Downsizing constitutes a major trend for several new EVAR devices. The Endurant device helped blaze the lower-profile path, introducing a device delivered in an 18-Fr catheter for 23- to 25-mm diameter aortic stent grafts. Endurant received Food and Drug Administration marketing approval in 2010, and results from the U.S. pivotal trial for this device appeared last year (J. Vasc. Surg. 2011;54:601-8). In the pivotal trial, the major adverse event rate after 30 days was 4%; after 1 year, the patency rate was 97%, no patients had type I endoleaks, and the rate of secondary procedures was 5%, said Dr. Dittmar Böckler, professor and medical director of vascular surgery at the University of Heidelberg (Germany). An even smaller version of the same device, Endurant II, places a 28-mm bifurcated segment of an aortic stent graft into an 18-Fr delivery catheter – reduced from 20 Fr in the existing Endurant device – and has longer limbs to maximize coverage, changes that will further "expand options" for this device, he said.
Other EVAR devices take the downsizing trend even further. The Ovation Abdominal Stent Graft System, which received FDA marketing approval last November, has a 14-Fr outer diameter. For the time being, Ovation "is the lowest-profile commercially available device, expanding the population that is suitable for EVAR," said Dr. Horst Sievert, director of the cardiovascular center at Sankt Katharinen Hospital in Frankfurt, Germany. The FDA also made Ovation the first EVAR to be approved as a humanitarian use device (defined as an instrument aimed at a U.S. patient population that grows by fewer than 4,000 new cases annually). Ovation is approved for use in patients with iliac or femoral artery access that is less than 7 mm in diameter, and for treating an aorta with an inner neck diameter of 15.5-17.4 mm. The clinical trial results for Ovation showed "excellent short-term results," Dr. Sievert said. In the U.S. pivotal trial with 161 patients, the major adverse event rate after 1 month was 2.5%, he noted.
The Zenith Low Profile, a third low-profile EVAR device delivered in a 16-Fr sheath, is nearing marketing approval. The FDA already has data from a U.S. pivotal trial with 120 patients, and a decision on marketing approval should come sometime this year, said Dr. Roy K. Greenberg, a vascular surgeon at the Cleveland Clinic. Although he voiced enthusiasm for lower-profile devices that allow EVAR in patients who would not be able to accommodate larger devices, he also cautioned that "as we get lower-profile devices, we need to pay more attention to iliac disease. Postimplantation residual stenosis is critical for patients with [calcified] iliac disease."
Another issue with new devices is establishing their long-term performance. "New devices aren’t necessarily better; they’re just different. I think there are some advantages to new devices, but we don’t have a track record with respect to their long-term behavior," Dr. Greenberg said.
Finally, the INCRAFT low-profile EVAR device starts testing in a pivotal U.S. trial in February. INCRAFT matches Ovation with a 14-F outer-diameter delivery sheath, said Dr. Robert M. Bersin, medical director of endovascular services at Swedish Medical Center in Seattle. Its track record so far comes from the first 60 patients who received the device, at six centers in Germany and Italy, he added.
• High aortic neck angles. Aside from size, the aortic-neck angle provides another opportunity to broaden the EVAR device market. The Aorfix EVAR device is highly flexible and designed to deal with aortic neck angles of 60 degrees or greater. The stent has a "unique design, because a 60-degree angle is typically an exclusion for most [EVAR] devices," said Dr. William A. Gray, director of endovascular services at Columbia University in New York.
He reviewed the roll-in phase data from the PYTHAGORAS trial, which enrolled 62 patients with aortic neck angles smaller than 60 degrees; two-thirds of these first-phase patients had necks angled at more than 45 degrees. In the roll-in phase, "the Aorflex device has given excellent results in patients with typical anatomy," and the results serve "as a good prelude to the high-angle cases," he said.