The extended use of clopidogrel (Plavix) in patients with drug-eluting stents reduced the risk for death or myocardial infarction (MI) in an observational study of more than 4000 patients undergoing initial percutaneous coronary intervention (PCI) with bare-metal or drug-eluting stents (JAMA. 2007; 297:159-168).

The participants had an initial PCI involving at least 1 bare-metal stent between January 2000 and July 2005 or at least 1 drug-eluting stent between April 2003 and July 2005. All patients were evaluated at 6, 12, and 24 months through September 7, 2006.

Primary end points were death, nonfatal MI, and the composite of both at 24 months. Among patients with drug-eluting stents who were event-free at 6 months, clopidogrel use was a significant predictor of lower adjusted rates of death.

Continued improvements were seen in patients with drug-eluting stents who were still taking clopidogrel at 12 months (P = .004) and at 24 months (P = .001) compared with those who had stopped taking it. However, no differences in death or MI events were seen between those with bare-metal stents who were taking clopidogrel and those who did not take the drug.  

“The paper shows that patients who reported taking clopidogrel more than 6 months after implantation of a drug-eluting stent had a lower rate of death and myocardial infarction compared with patients who did not take clopidogrel beyond 6 months,” coinvestigator David F. Kong, MD, of Duke University Medical Center, tells IMWR.

In fact, he says, patients with drug-eluting stents who took clopidogrel beyond 6 months had the lowest rate of death or MI at 2 years (3.1%). In contrast, those who did not take clopidogrel beyond 6 months had an event rate that was more then twice as high (7.2%) as those taking clopidogrel for more than 6 months.  

“These outcomes straddle the rates of death or myocardial infarction for bare-metal stent patients (6.0% without clopidogrel; 5.5% with clopidogrel). Consequently, the long-term benefit of drug-eluting stents appears to hinge on whether the patient is able to take clopidogrel for longer than 6 months,” Dr Kong says.

The American Heart Association recently issued an advisory cautioning against the early discontinuation of dual antiplatelet therapy (J Am Coll Cardiol. 2007;49: 734-739) that includes information that “differs from earlier recommendations, where therapy for 3 to 6 months was previously thought sufficient,” Dr Kong says.

ONLINE EXTRA
Recommendations for antiplatelet therapy and stent placement

Dr Kong summarized some of the key points included in the advisory:
• Before implanting a stent, the physician should discuss the need for antiplatelet therapy with the patient. In patients not expected to comply with 12 months of thienopyridine therapy for whatever reasons, a bare-metal stent should be strongly considered.

• In patients who are likely to require surgery within 12 months of receiving a stent, a bare-metal stent or balloon angioplasty with a provisional stent should be considered instead of the routine use of a drug-eluting stent.

• Healthcare professionals must make a greater effort to educate patients before hospital discharge about the reasons for prescribing thienopyridines and for taking dual antiplatelet therapy, as well as the risks associated with early discontinuation.

• Patients should be specifically instructed to contact their cardiologist before stopping any antiplatelet therapy, even if directed to do so by another healthcare provider.

• Healthcare providers who perform invasive or surgical procedures should be aware of the potentially catastrophic risks of prematurely stopping thienopyridine therapy and should contact the patient’s cardiologist to discuss optimal management.

• Elective procedures that carry a risk of bleeding should be delayed until 1 month after the patient has completed an appropriate course of thienopyridine therapy, which is ideally 12 months after receiving a drug-eluting stent in patients who are not at high risk of bleeding and at least 1 month after receiving a bare-metal stent.

• For patients who receive a drug-eluting stent and who must have procedures that mandate stopping thienopyridine therapy, aspirin should be continued whenever possible and the thienopyridine restarted as soon as possible after the procedure (due to concerns about late stent thrombosis).

“As an interventional cardiologist, I implant both drug-eluting and bare-metal stents,” Dr Kong says. “For bare-metal stent patients, I prescribe clopidogrel therapy for at least 28 days and aspirin indefinitely. For drug-eluting stent patients, I prescribe clopidogrel for at least 12 months and aspirin indefinitely.”