Dual anti-platelet therapy after coronary artery bypass grafting: is there any benefit? A systematic review and meta-analysis.

BACKGROUND: Anti-platelet therapy is an important component of medical therapy post coronary artery bypass grafting (CABG). While aspirin administration is a Class I indication after CABG, the benefit of concomitant clopidogrel is a controversial issue.

METHODS: We searched OVID Medline, Cochrane, Scopus, and EMBASE for randomized control trials and observational studies comparing aspirin ± placebo to aspirin + clopidogrel after CABG.

RESULTS: Eleven articles (five randomized control trials and six observational studies) including 25,728 patients met inclusion criteria. Early saphenous vein graft occlusion was reduced with the use of dual anti-platelet therapy (risk ratio (RR) = 0.59, 95% CI 0.43-0.82, p = 0.02). In-hospital or 30-day mortality was lower with aspirin + clopidogrel (0.8%) compared to aspirin alone (1.9%) (p < 0.0001), while risk of angina or perioperative myocardial infarction was comparable (RR = 0.60, 95% CI 0.31-1.14, p = 0.12). Patients treated with aspirin + clopidogrel demonstrated a trend towards a higher incidence of major bleeding episodes as compared to patients treated with aspirin alone (RR = 1.17, 95% CI 1.00-1.37, p = 0.05). In a pooled analysis of studies involving off-pump CABG compared to aspirin alone, dual anti-platelet therapy reduced the risk of perioperative myocardial infarction and saphenous graft occlusion by 68% (47% to 71%) and 55% (2% to 79%) respectively.

CONCLUSION: Dual anti-platelet therapy after CABG improved early saphenous vein graft patency, but may increase the risk of bleeding. The use of dual anti-platelet therapy appears to be most beneficial in patients undergoing off-pump CABG. Prospective randomized studies are necessary to determine whether this beneficial effect of dual therapy is also achieved in patients undergoing on pump CABG.