Veterans Administration Study Evaluates Prolonged Clopidogrel Use After Stenting

June 5, 2012—Findings from the Veterans Administration Drug-Eluting Stent Study of prolonged clopidogrel use after bare-metal and drug-eluting stent placement were published by David Faxon, MD, et al online ahead of print in Circulation: Cardiovascular Interventions.

The background of the study is that current guidelines recommend combining clopidogrel with aspirin for up to 1 year after coronary stenting, but the value of clopidogrel beyond this time is uncertain, stated the investigators.

As summarized in Circulation: Cardiovascular Interventions, the investigators evaluated all patients in the Veterans Administration health care system receiving either drug-eluting or bare-metal stents from 2002 to 2006. The Veterans Administration National Patient Care and Pharmacy databases were used to extract patient characteristics, duration of clopidogrel use, and outcomes for up to 4 years after the index procedure. Cox proportional hazards were used to estimate hazard ratios for death, myocardial infarction, revascularization, and bleeding from a 12-month landmark after stenting that excluded patients with events within the first 12 months.

The investigators reported that 29,175 of 42,254 patients met the study inclusion criteria. Compared with ≤ 12 months of clopidogrel, prolonged clopidogrel (> 12 months) was associated with a lower adjusted risk of death for both drug-eluting stents (hazard ratio [HR], 0.7; 95% confidence interval [CI], 0.61, 0.82; P < .01) and bare-metal stents (HR, 0.85; 95% CI, 0.76, 0.96; P = .01), as well as for death and myocardial infarction, but was unrelated to stroke or major bleeding. The effect of prolonged clopidogrel on death or myocardial infarction was significantly greater among patients receiving drug-eluting (HR, 0.7; 95% CI, 0.64, 0.84) compared with bare-metal stents (HR, 0.88; 95% CI, 0.79, 0.98; interaction P = .024).

The data showed that patients receiving clopidogrel beyond 12 months had a lower risk of death or myocardial infarction compared to patients receiving clopidogrel for ≤ 12 months. The risk reduction was greater for those receiving drug-eluting stents. These data support longer durations of dual-antiplatelet therapy for patients receiving a stent, particularly those receiving a drug-eluting stent, concluded the investigators in Circulation: Cardiovascular Interventions.