FDA OK’s Boston Scientific Stent Despite Risks

The U.S. Food and Drug Administration (FDA) just approved a controversial Boston Scientific heart stent, despite risks. The risks, though rare, are potentially significant; however, because benefits outweigh potential risks, the FDA approved the Promus Element Plus drug-eluting heart stent. What’s more, Boston Scientific’s request for pre-market approval came seven months sooner than expected.

We just wrote that the FDA was investigating a new class of heart stents and dangerous changes that can occur in the stents after implantation. The Promus Element Plus—tiny, mesh, tubular heart devices—can shrink or lengthen. The device is currently sold outside of the U.S.

Reuters explained that the Promus Element is designed as thinner and more flexible to better ease artery implantation; however, complaints include the device deforming in instances in which the artery is calcified, a blood vessel twists, or implantation is not appropriate. “While additional data collection is ongoing and will continue into the post-market, the totality of the information available and considering the addition of appropriate information in the labeling led to the conclusion that the Promus Element provides a reasonable assurance of safety and effectiveness,” an FDA spokeswoman told Reuters via email.

According to the agency, the problem—longitudinal deformation, tends to occur in Boston Scientific’s Ion stent, which received United States approval this year, as well as in the Promus Element. The FDA said it felt both stents are safe when used for approved indications, but was collaborating with Boston to better understand the issues.

The Promus Element Plus approval will enable the manufacturer to replace the Promus stent it co-markets with Abbott Laboratories; Boston Scientific will market the U.S. stent immediately and is pending Japan approval, which it expects by mid-2012, said Reuters.

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 the 133 patients who reported longitudinal stent deformation, new stents were implanted in 76 patients and 4 patients underwent surgery. “While we continue to watch this issue closely, we think that the Promus Element approval may indicate that FDA is not overly concerned about longitudinal compression,” Michael Matson, an analyst with Mizuho Securities, wrote in a research note, Reuters reported.

Meanwhile, some 600,000 angioplasties with and without stents are performed in the U.S. annually, costing over $12 billion; angioplasty, which usually involves the use of heart stents to widen blocked blood vessels, can result in clotting, which can increase heart attack and stroke risks in people with no heart symptoms. Drug-eluting stents, such as the Promus and Ion, 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 risk for clotting and heart attack.

Reuters noted that heart stents have come under scrutiny after research indicated that conventional medication and exercise might be better for some versus implantation with the devices. We wrote that in 2008, the COURAGE (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation) study published in the New England Journal of Medicine found that stents were no better than drugs in treating patients suffering from chronic, but stable, chest pain.

Stent giant, Boston Scientific has had issues in the wake of a number of stent recalls as far back as 2004, as well as issues over its problematic 2006 acquisition of stent and pacemaker manufacturer, Guidant Corp., Reuters explained previously. This year, Johnson & Johnson announced it would no longer be making drug-eluting stents; the devices are still manufactured by Medtronic Inc. and Abbott Laboratories Inc.