Outcomes of patients receiving clopidogrel prior to cardiac surgery.

BACKGROUND: Clinical impact of the concomitant clopidogrel therapy on clinical outcomes in patients undergoing cardiac surgery is unclear. We aimed to pool and systematically analyze outcomes in clopidogrel-treated patients undergoing cardiac operations to achieve greater statistical power and to define precise effect-estimates. METHODS: PubMed and Central databases were searched for relevant studies published between January 2001 and May 2010. The main outcome measures were the rates of red blood cell (RBC) transfusion, reoperation, myocardial infarction and postoperative mortality. The outcome parameters were pooled with the random-effect model via generic-inverse variance-weighting. RESULTS: Twenty studies comprising a total number of 23,668 patients were analyzed. Pooled analysis revealed that the administration of clopidogrel had a higher risk for postoperative mortality (OR: 1.24; 95% CI: 1.03-1.49, p=0.03) that was consistent among studies. The rates of myocardial infarction were similar between groups. Clopidogrel-exposed patients were associated with a significantly higher rate of RBC transfusion (OR: 1.82; 95% CI: 1.40-2.37; p<0.00001) and reoperation (OR: 2.15; 95% CI: 1.38-3.34; p<0.00001), although there was a marked heterogeneity among studies. According to subgroup analysis the mortality and the rates of transfusions were higher in studies in which clopidogrel was not discontinued 5 days prior to surgery, while the higher risk for reoperation was only apparent in studies published before 2006. CONCLUSION: Meta-analysis of observational studies demonstrated that concomitant treatment with clopidogrel before cardiac surgery is associated with a significant risk of bleeding-related complications and with a higher mortality.