Coronary Artery Bypass Graft Clinical Study Of Dual-antiplatelet Therapy

Part 1:Effect of aspirin-clopidogrel combination therapy on graft patency after coronary artery bypass surgery:randomised controlled trialObjectives:The aim of this study was to assess the efficacy of aspirin-clopidogrel combination therapy versus aspirin alone in preventing early postoperative graft occlusion following on-pump and off-pump coronary artery bypass surgery.Background:According to literature report, aspirin and clopidogrel together could improve intracoronary stent patency in patients with stent revascularization and may reduce thrombosis-induced saphenous vein graft occlusion.Methods:In this prospective randomized controlled trial,249 patients were randomly assigned to 2 groups after successful primary coronary artery bypass grafting from December of 2007 to December of 2008. When postoperative chest tube drainage was =30 cc/h for 2 hours, daily clopidogrel (75 mg) and aspirin (100 mg) were initiated in 124 patients (Group AC) versus aspirin alone(100 mg) in 125 patients (Group A) for 3 months. Intraoperatively, graft flow was assessed with transit-time flowmetry(TTFM) in all patients. All the participants were invited for three-month clinical follow-up and 64-slice MDCTA analysis. Two blinded observers classified each graft as occluded or not. Generalized estimating equation(GEE) techniques was used to evaluate predictors of venous graft patency.Results:There was no difference with respect to preoperative risk factors between patient groups. Only one (0.4%) of 249 randomized participants died postoperatively within 3 months. Of the remaining 248,239 survivors(96.4%) completed clinical three-month follow-up and 224(90.3%) had 64-slice MDCTA scans,111 from group A and 113 from group AC. No significant difference in terms of major adverse cardiac-related events or death was found between the two groups. Intraoperative TTFM findings were similar in both aspirin and aspirin-clopidogrel groups. At 3-month MDCTA follow-up, patency was studied in 704 grafts of 224 patients,11 (1.6%) grafts could not be analyzed. The overall graft occlusion rate was 10.3%(35/340) in the aspirin group and 6.5%(23/353) in the aspirin plus clopidogrel group (P=0.073). Graft patency rates for saphenous vein grafts were 85.7%(198/231) versus 91.6%(219/239)(reletive risk,1.707;95%confidence interval,1.010-2.886;p=0.043), respectively. In the multivariate analysis, dual antiplatelet therapy independently increased venous graft patency (relative risk,1.996; 95%confidence interval 1.015-3.922; p=0.045). Other factors such as distal anastomosis diameter(relative risk,24.159; 95% CI 3.685-158.395; p=0.001), graft flow (relative risk, 1.045; 95%CI 1.005-1.088;p=0.029) and pulsation index(relative risk,0.438; 95%CI 0.309-0.622; p<0.001) are also strong predictors of venous graft patency at 3-months follow up.Conclusions:In our study population, aspirin-clopidogrel combination therapy increased venous graft patency over treatment with aspirin monotherapy in 3 months after coronary artery bypass graft surgery. Dual antiplatelet therapy was independently correlated with increased venous graft patency. Part 2:Evaluation of safety of aspirin-clopidogrel combination therapy early after coronary artery bypass graft surgeryObjectives:The purpose of this study was to assess the safety of dual antiplatelet therapy of aspirin plus clopidogrel early after coronary artery bypass grafting.Background:At present clopidogrel use in coronary surgery varies from center to center, probably owing to the known adverse effect of preoperative clopidogrel on.postoperative hemostasis. But little is known regarding the safety profile of clopidogrel when initiated in the early postoperative setting.Methods:In this randomized controlled trial,249 patients were randomly assigned to 2 groups after coronary artery bypass grafting from December of 2007 to December of 2008. Daily clopidogrel (75 mg) and aspirin (100 mg) were initiated in 124 patients (Group AC) versus aspirin(100mg) alone in 125 patients (Group A) when postoperative chest tube drainage was=30 ml/h for 2 hours. Demographic, operative, and postoperative data were compared between groups. The effects of the antiplatelet regimen on chest tube drainage were compared according to patient characteristics and other procedural characteristics using a linear regression model.Results:There was no difference in terms of preoperative and intraoperative risk factors between groups. Total chest tube drainage and drainage after patients received antiplatelet agents were not significantly different between treatment groups. Aspirin-clopidogrel combination therapy did not increase the incidence of reexploration, transfusion, or the quantity of blood products transfused. No perioperative mortality or extrathoracic bleeding occurred in either group, and no difference was observed in the total number of days in ICU or in hospital between group A and group AC. Preoperative LVEF and operation time were significant predictors of bleeding from the time of antiplatelet administration on multivariable analysis. Early postoperatively use of dual antiplatelet therapy was not associated with increased bleeding after coronary artery bypass grafting.Conclusions:The present study suggests that according to a predefined administration protocol,dual antiplatelet therapy of aspirin and clopidogrel can safely be administered in-the early postoperative period in CABG patients, without increasing the risk of bleeding complications.