The U.S. Food & Drug Administration (FDA) is requiring a warning on the new Boston Scientific heart stent. The agency continues to investigate a rare and serious health issue with Boston Scientific Corp.’s new device, the Promus Element.
The FDA mandated Boston Scientific warn physicians about the issue when the device was approved in November, said Reuters. The Promus Element heart stent was approved, despite reports of the rare event that involves the device deforming following implantation, an event known as longitudinal stent deformation.
Longitudinal stent deformation happens in stents made by Medtronic Inc and Abbott Laboratories Inc, but tends to occur most frequently with the Boston Scientific device, according to the FDA, said Reuters. As we’ve explained, the risks, though rare, are potentially significant; however, because benefits outweigh potential risks, the FDA approved the Promus Element Plus drug-eluting heart stent. Of note, Boston Scientific’s request for pre-market approval came seven months sooner than expected.
Reuters explained that the Promus Element’s thin struts could make the device more flexible, which helps surgeons implant the device in narrow or difficult-to-reach vessels. This could also make the Promus Element likelier to stretch or compress when being placed in a vessel, said Reuters. Some 600,000 angioplasties, with and without stents, are performed in the U.S. annually, costing over $12 billion. Angioplasty usually involves the use of heart stents to widen blocked blood vessels, which can result in clotting, and which, in turn, increases heart attack and stroke risks in people with no heart symptoms. Drug-eluting stents prop open unhealthy arteries, sending medication to help ensure vessels do not re-clog. When longitudinal deformation occurs, the stents deform within the vessel, which can create an increased clotting and heart attack risks.
“It’s a trade-off,” said Ashley Boam, director of the division of Interventional Cardiology Devices Branch at FDA, in an interview with Reuters. “It is still something we are looking at carefully,” she added. “Our impression at this point is that design does play a role. But the types of lesions the physician is trying to treat also plays a role,” Boam said.
Now, the FDA is mandating that Boston Scientific include a section about longitudinal compression on its product label, which is currently 20 pages long, said Reuters. The label now says, “Although the rate of longitudinal stent deformation is unknown, currently available information suggests that it is a rare adverse event.”
Stent deformation was discussed in two cardiology journals published in the United States and Europe as well as at the Transcatheter Cardiovascular Therapeutics meeting last month, said Reuters. Dr. Cindy Grines, a cardiologist at the Detroit Medical Center Cardiovascular Institute and editor of the Journal of Interventional Cardiology, said she did not know about the warning, writing about it in her publication, reporting it to the agency and the device maker. “It’s good there’s a warning, but it needs to be advertised to the interventional cardiology community. We’re a high volume center and I haven’t heard about it,” she said, noting that a warning buried in a label is not of great help, “Nobody reads the labels,” she pointed out, said Reuters.
“When there’s a new device like (Promus Element) that’s not a game changer and then you find out there may be issues, you tend not to want to use it,” Dr. Mark Ricciardi, director of Interventional Cardiology at the University of New Mexico Health Science Center, told Reuters. “Having a warning on the label doesn’t completely say ‘Do not enter,’ but it makes you think.”
Boston Scientific told Reuters that as of October 31, it was aware of 136 longitudinal stent deformation events per 829,372 units sold, worldwide. Of 133 patients reporting longitudinal stent deformation, new stents were implanted in 76; 4 underwent surgery.