Effect of aspirin plus clopidogrel therapy on aspirin resistance after off-pump coronary artery bypass surgery

Abstract

To investigate the effect of the anti-platelet effect of aspirin plus clopidogrel on off-pump coronary artery bypass (OPCAB) grafting and the possible side effects of such therapy. Sixty patients who underwent standard OPCAB were randomized immediately after surgery in two groups: the aspirin alone group of 30 patients who received aspirin (100 mg) daily; and the combination group of 30 patients who received clopidogrel (75 mg) plus aspirin (100 mg) daily. Platelet aggregation in response to arachidonic acid (PLAA) and adenosine diphosphate (PLADP) were measured at baseline (before surgery) and 1-6, 8, and 10 days after the medication. Postoperative bleeding and other perioperative parameters were compared between these two groups. There were no significant differences between the two groups in perioperative findings including average number of distal anastomosis, operative time, postoperative bleeding, ventilation time, and intensive care unit stay (all P>0.05). The proportion of patients with the PLAA above 20% value was significantly lower in the combination group than those in the aspirin alone group (32.1% vs 62.1%, P<0.05). PLAA of two groups one and two days after taking aspirin or plus clopidogrel were (24.2±31.9)% vs. (49.6±32.6)% and (13.8±27.2)% vs. (37.6±37.4)%, respectively (P<0.05). No obvious postoperative complication was noted in both groups. Multivariate analysis showed that clopidogrel administration was independently correlated with aspirin resistance (P=0.044, OR = 0.09;95% CI=0.07-0.48). Early combined use of aspirin plus clopidogrel after OPCAB can remarkably reduce OPCAB-related aspirin resistance and enjoy similar safety.