Patients who receive the anti-platelet medication clopidogrel following an acute coronary syndrome (such as heart attack) appear to be at greater risk of a heart attack or death in the first 90 days after stopping clopidogrel treatment, according to a study in the February 6 issue of JAMA: The Journal of the American Medical Association.
Randomized trials have established the effectiveness of clopidogrel therapy following hospitalization for acute coronary syndrome (ACS) for patients treated either medically or with percutaneous coronary intervention (PCI - procedures such as balloon angioplasty or stent placement used to open narrowed coronary arteries). Current cardiology guidelines recommend clopidogrel therapy for ideally up to 1 year for patients treated medically or with a bare metal stent, according to background information in the article. It is unknown whether there may be a “rebound effect” or concentration of thrombotic events shortly after stopping treatment with clopidogrel, as has been found for patients after long-term aspirin therapy.
P. Michael Ho, M.D., Ph.D., of the Denver VA Medical Center, Denver, and colleagues assessed the incidence and timing of death or acute myocardial infarction (AMI; heart attack) after stopping treatment with clopidogrel in a group of 3,137 patients with ACS discharged from 127 Veterans Affairs hospitals. Average follow-up after stopping treatment with clopidogrel was 196 days for medically treated patients with ACS without stents (n = 1,568) and 203 days for patients with ACS treated with PCI (n = 1,569).
Among the medically-treated patients, the average duration of clopidogrel treatment was 302 days. The researchers found that all-cause death (n = 155) or AMI (n = 113) occurred in 17.1 percent (n = 268) of patients, with 60.8 percent (n = 163) of events occurring during 0 to 90 days, 21.3 percent (n = 57) occurring during 91 to 180 days, and 9.7 percent (n = 26) occurring during 181 to 270 days after stopping treatment with clopidogrel. Further analysis indicated that the interval of 0 to 90 days was associated with nearly twice the risk of adverse events after stopping treatment with clopidogrel compared with the interval of 91 to 180 days.