After more than two years of clinical data linking drug-eluting stents (DES) with an increased risk of stent thrombosis compared to their bare-metal cousins, a recent study in the Journal of the American Medical Association (JAMA) may shed some positive light on the DES space.
According to the study, published in the June 25 issue, the widespread use of DES is associated with a decrease in the need for repeat procedures to unblock coronary arteries without an increased risk of death, compared to bare-metal stents (BMS).
"This large observational study is better powered than were prior randomized studies to detect the consequences of a difference in stent thrombosis rates between drug-eluting and bare-metal stent recipients, and it may better reflect real-world use of these devices, including for off-label indications," Howard Herrmann, MD, said last week in Journal Watch Cardiology.
Herrmann noted that an increased risk for late stent thrombosis has been associated with DES in some studies. However, he said, "If such an increase occurred in this study, it was more than offset by a decrease in the risk for restonenosis and events arising from its treatment."
David Malenka, MD, of Dartmouth-Hitchcock Medical Center (Lebanon, New Hampshire), and colleagues performed the study to compare the rates of revascularization, heart attack and survival, before and after the availability of DES. The study included 38,917 Medicare patients who underwent non-emergency coronary stenting from October 2002 through March 2003 when only BMS were available and 28,086 similar patients who underwent coronary stenting from September through December 2003, when 61.5% of patients received a DES and 38.5% received a BMS. Follow-up data were available through December 2005.
Only one DES – the Cypher from Cordis (Miami Lakes, Florida), a subsidiary of Johnson & Johnson (New Brunswick, New Jersey), was approved for sale in the U.S. in 2003, during the time period of the study's DES-era group. Boston Scientific's (Natick, Massachusetts) was approved in 2004.
Both the Taxus and the Cypher – while initially rushing to about $5 billion in combined sales – have experienced declining sales as the result of negative clinical data, and a series of reports raising questions about the overall value of DES devices.
During the two years of observation, 22.8% of patients in the BMS-era group received a repeat procedure to unblock coronary arteries. In comparison, only 19% of the DES-era group underwent a repeat revascularization, a decrease of about 18%, the authors noted.
The overall death risks at two years were the same for both groups, 8.4%, but there was a slight decrease in heart attacks from 2.4% to 2%.
"Although such an analysis will not answer the question of what is the true rate of stent thrombosis with drug-eluting stent vs. the rate with bare-metal stent, it does address the important question of whether, on-average, the population of stented patients is being helped or hurt by the widespread use of this technology," the authors wrote.
"Although other data may suggest some incremental risk of stent thrombosis with the use of drug-eluting stents, we can detect no adverse consequence to the health of the population. We speculate that whatever the increased risk of stent thrombosis associated with drug-eluting stent use is, it is more than offset by a decrease in the risk of developing restenosis [renarrowing of a coronary artery after angioplasty] and the attendant risk of a procedure to treat that restenosis."
The National Institute on Aging and the Robert Wood Johnson Foundation (Princeton, New Jersey) paid for the study.
Another recent study, this one by researchers from the University of Pennsylvania School of Medicine (Philadelphia), also helped ease DES fears by finding that patients who receive a DES are less likely to die, have a heart attack, or require follow-up surgery than those who receive a BMS. The findings, published last month in the Journal of the American College of Cardiology, showed a "clear, lifesaving benefit of drug-eluting stents compared to bare-metal stents" among elderly patients in the two years following placement of the stent (MDD, May 28, 2008).
Given the roll-out this year of second-generation DES devices, the study could indicate an even greater benefit of the newer coated stents, which appear to have reduced risks compared to the first generation.
Medtronic (Minneapolis) received FDA approval for its Endeavor DES in February, making it the first in the DES 2.0 family of these devices to win approval (MDD, Feb. 4, 2008). The Endeavor received a panel recommendation for approval in October (MDD, Oct. 10, 2007) and the Xience stent from Abbott Laboratories (Abbott Park, Illinois) is expected to be the next to win approval, having received a positive panel recommendation in early December (MDD, Dec. 3, 2007).
Joe McGrath, a Medtronic spokesman, declined to comment on the recent JAMA study because it did not involve any of Medtronic's devices. The Endeavor has never had any of the safety issues that have plagued the first generation devices, he told Medical Device Daily.