Safety of clopidogrel being continued until the time of coronary artery bypass grafting in patients with acute coronary syndrome: a meta-analysis of 34 studies

Guidelines suggest that patients should discontinue clopidogrel for 5 days prior to coronary artery bypass grafting (CABG) where possible. Those with acute coronary syndrome (ACS) are at elevated risk of further myocardial infarction (MI) and death without clopidogrel. This meta-analysis aims to determine the risk of CABG in ACS patients while continuing clopidogrel.

Thirty-four studies with 22 584 patients undergoing CABG were assessed. Patients with recent clopidogrel exposure (CL) were compared with those without recent clopidogrel (NC). Although mortality is increased in CL vs. NC [odds ratio (OR) 1.6, 95% CI 1.30–1.96, P < 0.00001], it is influenced by the ACS status and case urgency in these mainly non-randomized studies. In ACS patients, there is no significant difference in mortality (OR 1.44, 95% CI 0.97–2.1, P= 0.07) or in postoperative MI (OR 0.57, 95% CI 0.31–1.07, P = 0.08) and stroke rates (OR 1.23, 95% CI 0.66–2.29, P = 0.52). Combined major adverse cardiovascular event (stroke, MI, and death) was not different in the two groups (OR 1.10, 95% CI 0.87–1.41, P= 0.43). Reoperation rates are elevated on clopidogrel but have reduced over time, and were specifically not different in ACS patients (OR 1.5, 95% CI 0.88–2.54, P= 0.13).

Previous studies focused on surrogate endpoints and compared higher risk ACS patients with elective cases. However, many patients have safely undergone CABG on clopidogrel and surgical expertise is growing. Multinational trials are required to fully determine the balance of ischaemia and bleeding. While results are awaited we suggest ACS patients requiring urgent CABG proceed with surgery without delay for a clopidogrel-free period.