Clopidogrel Better than Aspirin for High-Risk Patients

Laurie Barclay, MD

January 22, 2004

Jan. 22, 2004 -- For high-risk patients who have had a myocardial infarction (MI) or stroke, clopidogrel is significantly better than aspirin in preventing recurrent cardiovascular events, according to an analysis of data from the Clopidogrel Versus Aspirin in Patients at Risk of Ischemic Events (CAPRIE) trial published in the February issue of Stroke.

"Just because a patient came in with a heart attack today doesn't mean he or she is only at risk for a future heart attack," coauthor Deepak L. Bhatt, MD, from the Cleveland Clinic Foundation in Ohio, says in a news release. "The next time, it may be a stroke or other arterial problem."

In the CAPRIE trial, patients with a history of MI or stroke were randomized to receive either clopidogrel or aspirin after a cardiovascular event (CVE). Overall, risk of recurrent CVE was 8.7% lower in those who received clopidogrel than in those who received aspirin.

In a subgroup of 4,496 high-risk patients followed after a second CVE, the clopidogrel group had a 14.9% lower relative risk of recurrent CVE than the aspirin group. Risk of a subsequent CVE was higher in patients who had already had two CVEs, even if the second or third event was not necessarily the same as the first.

"The third event may be fatal," Dr. Bhatt said. "If a patient has a history of multiple [CVEs], they are better off being treated with clopidogrel rather than aspirin."

After one- and three-year follow-ups, patients receiving clopidogrel were less likely than those receiving aspirin to have been hospitalized for or to have died from a CVE.

One year after their second event, 16.1% of the clopidogrel group and 18.5% of the aspirin group had had an ischemic stroke, MI, or repeat hospitalization for CVE. The composite end point of ischemic stroke, MI, or vascular death was reached in 8.8% of the clopidogrel-treated patients and in 10.2% of the aspirin-treated patients.

After three years, 32.7% of the clopidogrel group and 36.6% of the aspirin group had had another CVE, and vascular death had occurred in 20.4% of the clopidogrel group and in 23.8% of the aspirin group. Based on these findings, treating 29 very high-risk patients with clopidogrel would prevent one vascular death, MI, or ischemic stroke over three years.

Study limitations include post-hoc analysis and lack of power to detect differences in cerebrovascular, coronary, and peripheral arterial events as predictors of further CVEs.

"The absolute benefit of clopidogrel over aspirin seems to be amplified in high-risk patients, whereas the relative benefit is similar across end points related to vascular ischemia," the authors write.

Stroke. 2004;35:000-000

Reviewed by Gary D. Vogin, MD