Medical Device Daily Washington Editor
WASHINGTON — Just when doctors thought it was safe to go back into the deep waters of the drug-eluting stent (DES) market and leave the shallow end of the stent pool — the part occupied by the bare-metal stent (BMS) — someone with imagination, pluck and a lot of drive makes the shallow end look a lot deeper.
In fact, it's a lot more than just one person filling out the BMS end of the pool, as one of the sessions held on the second day at the 20th anniversary edition of Transcatheter Cardiovascular Therapeutics (TCT 2008), sponsored by the Cardiovascular Research Foundation (New York), clearly demonstrated. And while it seems unlikely that the DES is destined for oblivion as a result, it is quite clear that researchers think there is a lot of mileage left in the BMS.
Speaking on the subject of one such technology was Alexandre Abizaid, MD, chief of coronary interventions at the Dante Pazzanese Institute of Cardiology (Sao Paulo, Brazil), who offered some early returns on the Nuloy BMS, made by Icon Interventional (Atlanta). Regarding the characteristics of the device, Abizaid said the Nuloy stent improves "deliverability, radiopacity, radial strength and recoil." Much of the real advantage of the Nuloy, however, is based on the stent's skinny but sturdy struts.
Abizaid said that animal model studies have produced no difference in outcomes between stainless steel and Nuloy foils, "indicating no adverse biological reactions."
However, the Nuloy is a lot thinner than much of the competition. Abizaid said the Nuloy's struck thickness is a mere 64mm wide, a slim item compared to the heftier Cypher, made by Cordis (Miami Lakes, Florida), which he said is 140mm wide.
Without citing specific references, Abizaid said "the clinical value of thin struts have been shown in several studies," and he added that the Nuloy exhibited a 20% lower device profile inside the vessel compared to the Cypher. He said that among the next steps for the device are a CE mark study and a PMA study.
Despite the enthusiasm for a non-DES product, the early success of this naked stent has not deterred Icon from eyeing the DES market. Abizaid told the audience that the company has taken out a license with Ariad Pharmaceuticals (Cambridge, Massachusetts) to use that company's rapamycin analogue, deforolimus, as an antiproliferative (Medical Device Daily, Oct. 15, 2007) for future DES development.
Mark Bates, MD, professor of medicine and surgery at West Virginia University (Charlestown, West Virginia) and the CEO of Nexeon MedSystems (also Charlestown) discussed his company's Protex cobalt alloy stent. The stent does not elute drugs, but is nonetheless, as one might gather, not precisely a bare-metal device inasmuch as it comes with a "pro-healing" coating.
Bates described the stent as "a marriage of two technologies." Based on the company's Riviera cobalt stent and coated with a substance called Finale, made by Surmodics (Eden Prairie, Minnesota), the device is designed to prop open the artery and to speed the healing of that artery.
Bates said the company's inversion point technology "is a cobalt alloy technology that uses a simple concept" involving crimping of the stent's struts. He said the Protex comes in at about 77 micrometers mm. This skinny strut does not disappear during radiological examinations, Bates said. "We found that in a pig model, it had equivalent visibility to cobalt alloys." The hoped-for benefit of the Finale coating, which Bates described as a protein layer that attracts "endothelial progenitor cells," is faster healing and perhaps less antiplatelet therapy.
"When you put this stent in endothelial cell culture, you'll see attachment of cells within 30 minutes," Bates said, and a 14-day rabbit model indicated "complete coverage" of the stent.
"We're taking the opposite approach to that of DES, trying to repopulate the" blood vessel lining, Bates said, adding that the first case coming back from the Protex I trial is encouraging. "Basically we see excellent stent behavior and performance," he said. As for antiplatelet therapy, the company's web site says, "only a short one-month antiplatelet therapy regimen is expected to be required."
For the interventionist who is concerned about how well the end of a stent seats at the juncture of the aorta and one of the main coronary arteries, there is almost a new industry to help. One of the presentations at the meeting was by Tim Fischell, MD, chief scientific officer at Ostial Solutions (Kalamazoo, Michigan), who discussed the company's Ostial Pro stent positioning system.
Fischell described the Ostial Pro as "a new tool to help you position a stent at the aortal-ostial opening" with much more certainty and precision than is currently possible. He said, "the rationale [behind the device's development] is that angiographic landmarks are often ambiguous or misleading," which too often leads to misplaced stents. "The need to correctly position a stent is even more critical in the era of the DES," he said, adding that a positioning device "should be simple and nearly foolproof."
The company believes it is onto a substantial opportunity. Fischell said the market in 2008 is about 290,000 procedures worldwide. "This is not a trivial market or problem," he said.
The Ostial Pro is a four-prong guide that expands to the side when pushed past the end of the catheter and deploys against the aorta around the entry into the affected artery. The idea is to help the interventionist position the end of the stent so that the balloon can flatten out the end of the stent securely against the geometry of the coronary artery where the artery opens into the aorta. Fischell said with proper use, an interventionist can "get a flush, perfect alignment," and said the company's device has been used for dozens of cardiac and renal placements. He said the device is now being marketed after obtaining a PMA in June 2007 and is approved for coronary and other applications.
As for the device's pivotal PMA trial, Fischell said "the miss rate in the 30 control cases was 30%," but there were none in the study group. "This is a simple tool that is compatible with contemporary guiding catheters and stents," he said.