ASpirin and Plavix Following Coronary Artery Bypass Grafting (ASAP-CABG): A Randomized, Double-Blind, Placebo-Controlled Pilot Trial

Background: Vein graft thrombosis is the leading cause of acute graft failure within the first post-operative month. Several studies have shown the benefit of post-operative dual anti-platelet therapy (DAPT) in preventing acute graft thrombosis. The purpose of this study was to determine whether peri-operative initiation of DAPT will improve short and intermediate term graft patency.

Methods: This was a randomized, double-blind, placebo controlled trial of 20 patients undergoing CABG to compare DAPT versus aspirin monotherapy. The primary outcome was post-operative graft patency at 2 and 52 weeks determined by <50% bypass graft stenosis by cardiac computed tomography angiography (CCTA). The secondary outcomes were (1) major adverse cardiovascular events (MACE), defined as myocardial infarction, thrombotic events, and angina, and (2) safety end-points defined as TIMI major and minor bleeding events.

Results: The study population consisted predominately of men (19/20 patients). At 2 weeks, all LIMA grafts were patent although vein graft patency for the DAPT group was only 83.3% (20/24) compared to 89.5% (17/19) for placebo (p=0.597). At 52 weeks, the patency rate in the placebo group was 52.6% (10/19) as compared to a patency of 71.4% (15/24) in the dual anti-platelet therapy arm (p=0.244).

Conclusion: The addition of clopidogrel to aspirin post-bypass surgery did not significantly improve venous graft patency at 2 weeks but trended toward higher graft patency at 52 weeks.