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Longer anti-clotting treatment appears to lower the risk of death or a heart attack in patients with drug-eluting stents

Patients who receive drug-coated stents to open heart arteries may lower their risks of heart attack or death by taking an anti-platelet medication longer than current recommendations, according to a study supported by the Agency for Healthcare Research and Quality (AHRQ).

The drug, clopidogrel, is an anti-clotting medication currently recommended for 3 to 6 months after placement of "drug-eluting" stents, but the new observational study by AHRQ's DEcIDE Research Center at Duke University suggests the drug reduces risks of heart attack or death for at least 2 years in some patients.

How long clopidogrel may be needed, however, remains uncertain. The drug, which minimizes clotting by stopping blood platelets from sticking together, is currently recommended by the Food and Drug Administration for 3 or 6 months for drug-eluting stents, depending on the stent manufacturer.

The Duke study included 4,666 patients who received drug-eluting stents or bare metal stents during a 5-year period. Of those, 3,609 were defined as "event free," meaning they had not died, had heart attacks, or undergone additional procedures to open coronary arteries for at least 6 months since stent placement. Researchers then checked those patients' use of clopidogrel and their health status through September 2006. The study concluded:

• Among drug-eluting stent patients who were event free at 6 months, those who reported clopidogrel use were significantly less likely to die during the next 18 months than those who did not use the drug (a 2 percent death rate vs. a 5.3 percent death rate). These patients were also less likely to either die or have a heart attack (3.1 percent vs. 7.2 percent).
• Among patients who had been event free for a full year, those who reported clopidogrel use at 12 months were similarly less likely than those not taking clopidogrel to die during the next 12 months (0 percent vs. 3.5 percent), and less likely to either die or have a heart attack (0 percent vs. 4.5 percent). While the Duke study strongly suggests that patients with drug-eluting stents should take clopidogrel longer than current recommendations, a randomized controlled trial is needed to confirm these results, researchers said. In addition, further research is needed to assess the relationship between long-term clopidogrel therapy and its risks for serious adverse effects such as bleeding.

See "Clopidogrel use and long-term clinical outcomes after drug-eluting stent implantation," by Eric L. Eisenstein, D.B.A., Kevin J. Anstrom, Ph.D, David F. Kong, M.D., and others, in the December 5, 2006, online issue of JAMA 297, pp. E1-E10.

Editor's Note: The Duke study was funded by AHRQ's Effective Health Care (EHC) program (contract 290-05-0032). Authorized by the Medicare Prescription Drug, Improvement, and Modernization Act, the EHC program develops unbiased scientific evidence on the effectiveness of medical interventions. The Duke researchers are 1 of 13 teams nationwide that are part of AHRQ's DEcIDE (Developing Evidence to Inform Decisions about Effectiveness) network, which is part of the EHC. The network conducts new research to help patients, health care providers, and others make decisions about the effectiveness and safety of treatment options. For more information about DEcIDE and the EHC program, go to http://www.effectivehealthcare.ahrq.gov .

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