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Circulation: Cardiovascular Quality and Outcomes

Year: 2010  |  Volume: 3  |  Issue: 3  |  Page No.: 303 - 308

Adverse Events After Stopping Clopidogrel in Post-Acute Coronary Syndrome Patients: Insights From a Large Integrated Healthcare Delivery System

P. M Ho, T. T Tsai, T. Y Wang, S. M Shetterly, C. L Clarke, A. S Go, A Sedrakyan, J. S Rumsfeld, E. D Peterson and D. J. Magid

Abstract

Background— A prior study from the Veterans Health Administration found a clustering of cardiovascular events after clopidogrel cessation. We sought to confirm and expand these findings.

Methods and Results— This was a retrospective cohort study of 2017 patients with acute coronary syndrome discharged on clopidogrel from an integrated health care delivery system. Rates of all-cause mortality or acute myocardial infarction (MI) within 1 year after stopping clopidogrel were assessed among patients who did not have an event before stopping clopidogrel. Death/MI occurred in 4.3% (n=71) of patients. The rates of death/MI were 3.07, 1.62, 0.70, and 0.95 per 10 000 patient-days for the time intervals of 0 to 90, 91 to 180, 181 to 270, and 271 to 360 days after stopping clopidogrel. In multivariable analysis, the 0- to 90-day interval after stopping clopidogrel was associated with higher risk of death/MI (incidence rate ratio, 2.74; 95% confidence interval, 1.69 to 4.44) compared with 91- to 360-day interval. There was a similar trend of increased events after stopping clopidogrel for various subgroups (women versus men, medical therapy versus percutaneous coronary intervention, stent type, and ≥6 months or <6 months of clopidogrel treatment). Among patients taking clopidogrel but stopping ACE inhibitor medications, the event rates were similar in the 0- to 90-day versus the 91- to 360-day interval (2.67 versus 2.91 per 10 000 patient-days; P=0.91).

Conclusions— We observed a clustering of adverse events in the 0 to 90 days after stopping clopidogrel. This clustering of events was not present among patients stopping ACE inhibitors. These findings are consistent with a possible rebound platelet hyper-reactivity after stopping clopidogrel and additional platelet studies are needed to confirm this effect.

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