The literature search yielded 3 prospective randomized studies and 17 observational studies with valid data. Randomized studies were post hoc analyses of the
Clopidogrel as Adjunctive Reperfusion
Therapy (CLARITY),
Clopidogrel for the Reduction of Events During Observation (CREDO), and
Clopidogrel in
Unstable Angina to Prevent Recurrent Ischemic Events trials. Meta-analysis based on these data showed a nonsignificant reduced risk of immediate postoperative composite end point (death,
myocardial infarction, or
stroke) in the
clopidogrel group (risk ratio [RR], 0.77; 95% confidence interval [CI], 0.58-1.04). Data from the CREDO and CLARITY trials showed a similar risk of death (RR, 0.81; 95% CI, 0.20-3.37),
myocardial infarction (RR, 0.58; 95% CI, 0.25-1.33), and major
bleeding according to Thrombolysis in
Myocardial Infarction criteria (RR, 1.48; 95% CI, 0.72-3.04). Meta-analysis of observational studies showed that preoperative exposure to
clopidogrel was associated with an increased risk of death (RR, 1.30; 95% CI, 1.02-1.67), reoperation for
bleeding (RR, 1.88; 95% CI, 1.37-2.58), blood loss (mean difference, 157.8 mL; 95% CI, 61.9-253.6), need of packed
red blood cell transfusion (RR, 1.23; 95% CI, 1.10-1.37), and increased use of blood products. A significantly reduced risk of postoperative
myocardial infarction was observed among patients taking
clopidogrel (RR, 0.63; 95% CI, 0.48-0.82).
CONCLUSIONS: