NEW YORK (Reuters Health) – The combination of aspirin and clopidogrel is no better than aspirin alone for preventing saphenous vein graft (SVG) intimal hyperplasia after coronary artery bypass graft (CABG) surgery, researchers report in the December 6th online issue of Circulation.
Unlike aspirin, clopidogrel has previously been shown to inhibit the process of intimal proliferation and smooth muscle hyperplasia, but no study has evaluated whether clopidogrel inhibits SVG intimal hyperplasia or improves graft patency after CABG.
Dr. Marc Ruel from University of Ottawa Heart Institute, Ottawa, Ontario, Canada and colleagues used intravascular ultrasound to evaluate whether the addition of clopidogrel 75 mg to aspirin inhibits the development of SVG disease in a phase II, placebo-controlled clinical trial of 113 patients.
At 1 year after CABG, SVG mean intimal area, the primary outcome of the trial, didn’t differ significantly between the aspirin-clopidogrel and aspirin-placebo groups.
Other measures, including overall graft patency, internal thoracic artery graft patency, and SVG patency at 1 year, didn’t differ between the 2 treatment groups.
Major adverse cardiovascular events and freedom from major adverse cardiovascular events at 1 month and at 1 year were similar for aspirin-clopidogrel and aspirin-placebo, and there were no significant differences in the rates of perioperative or late bleeding between the 2 treatments.
Despite these findings, the investigators aren’t ready to exclude the possibility of a beneficial effect from the addition of clopidogrel: “The results of CASCADE cannot conclusively exclude an inhibitory effect of clopidogrel on the development of SVG disease after CABG because the study may have been underpowered.”
“A larger trial with clopidogrel or newer antiplatelet agents with purported advantages over clopidogrel may constitute important areas for future research targeting the inhibition of SVG disease after CABG,” they conclude.
The Bristol-Myers Squibb Sanofi Canada Partnership provided study medication and financial support for the trial. Two of the 9 authors received research support from the partnership for the conduct of this trial.
Reference:
Aspirin Plus Clopidogrel Versus Aspirin Alone After Coronary Artery Bypass Grafting
Circulation 2010;122:2680-2687.
