A new study funded by the Massachusetts Department of Public Health is showing further evidence to support the use of drug eluting stents over bare metal stents in heart attack patients. This study measured stent use specifically in diabetic patients. Drug-eluting stents showed improved outcomes as compared with bare metal stents in diabetics, and no excess adverse events were found with drug-eluting stents in diabetic patients. This data was reported by researchers at the American Heart Association’s Scientific Sessions 2008 in New Orleans. Some of the raw numbers appear marginal, but others are very impressive.
Drug-eluting stents reduced the risk of revascularization, heart attack and death in diabetics as compared with bare-metal stents in the largest observational comparison. The results were presented as a late-breaking clinical trial and is simultaneously published in circulation in the Journal of the American Heart Association.
People with diabetes make up about a third of all patients undergoing procedures to reopen blocked blood vessels. In the largest population-based comparison of stents in diabetics, researchers used data from a mandatory state registry. They identified 5,051 diabetics who underwent PCI at acute-care, non-federal hospitals between April 2003 and September 2004. Diabetic patients at those hospitals were about twice as likely to get DES compared to BMS (66.1% vs. 33.9%).
Laura Mauri, M.D., M.Sc., principal investigator of the study and assistant professor of medicine at Brigham and Women’s Hospital and Harvard Medical School in Boston, Mass. said: “We actually saw a significant benefit from using drug-eluting stents in this patient population…. First, they significantly reduced the need for repeat procedures which included repeat stenting or bypass surgery. Second, they were associated with lower rates of death and heart attack. So, as a result we can say that these stents appear to be safe in diabetic patients, whose diabetes puts them at higher risk of mortality and heart attack than the general population.”
Mauri also noted that at three years of follow-up, the unadjusted cumulative endpoint of death was 14.4% for drug-eluting stent patients compared to 22.2% for bare metal stents patients. The researchers then matched a subset of 1,476 DES and 1,476 BMS patients to control for 63 potential confounders such as concurrent conditions and medications. In that comparison, they found the risk-adjusted mortality at three years was 17.5% for DES patients vs. 20.7%, a small but significant 3.2 percent absolute reduction in mortality in DES patients, with no excess adverse events. The choice of BMS or DES was not randomized, but was done at the direction of the treating physician, so it is possible that the patients given DES were different in the number of blood vessel or other characteristics.
Although three-year data were not yet available for rates of heart attack and target vessel revascularization, at two years of follow-up those rates were lower in the DES group compared to the BMS group.
This study showed lower mortality and adverse events, and this study was also larger than many of the prior studies which have showed safety concerns and damaged the reputation of DES vs. BMS use.
The study did not show which exact stents were under comparison, but it does at least give some timeframes. Here are the companies making drug eluting stents:Cypher by Johnson & Johnson (NYSE: JNJ), and SurModics (NASDAQ: SRDX) is the molecule maker for Cypher; and Taxus by Boston Scientific (NYSE: BSX), and Angiotech (NASDAQ: ANPI) is the molecule maker for Taxus.
The newer stent players may benefit from this study, but these are newer on the market. Endeavor by Medtronic (NYSE: MDT) is a drug eluting stent system with approval in 2008. Abbot Laboratories (NYSE: ABT) by Xience was not on the market at that time. Abbott also supplies a private-label version of XIENCE V to Boston Scientific (NYSE: BSX) called the PROMUS.
Jon C. Ogg
November 11, 2008