Prolonged clopidogrel use after bare metal and drug-eluting stent placement: the Veterans Administration drug-eluting stent study.
BACKGROUND
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.


RESULTS
We evaluated all patients in the Veterans Administration healthcare 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. We used Cox proportional hazards 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. Of 42,254 patients, 29,175 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], 0.70; 95% confidence interval [CI], 0.61, 0.82; P<0.01) and bare metal stents (HR, 0.85; 95% CI, 0.76, 0.96; P=0.01) 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, 0.70; 95% CI, 0.64, 0.84) compared with bare metal stents (HR, 0.88; 95% CI, 0.79, 0.98; interaction P=0.024).


CONCLUSIONS
Patients receiving clopidogrel beyond 12 months had a lower risk of death or myocardial infarction compared patients receiving clopidogrel ≤12 months. The risk reduction was greater for drug-eluting stents. These data support longer durations of dual antiplatelet therapy for patients receiving a stent, particularly for those receiving a drug-eluting stent.
Cardiovascular Division, Veterans Affairs Boston Healthcare System, Boston, MA, USA. dfaxon@partners.org
David P
DP
Faxon
Elizabeth
E
Lawler
Melissa
M
Young
Michael
M
Gaziano
Scott
S
Kinlay
D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D001241:Aspirin / Q000008:administration & dosage; D000077144:Clopidogrel; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D054855:Drug-Eluting Stents; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D016015:Logistic Models; D008297:Male; D008670:Metals; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000209:etiology; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D057216:Propensity Score; D016016:Proportional Hazards Models; D011474:Prosthesis Design; D018570:Risk Assessment; D012307:Risk Factors; D015607:Stents; D013988:Ticlopidine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States; D014493:United States Department of Veterans Affairs / Q000706:statistics & numerical data
D008670:Metals; D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin