This, to some extent, may make preoperative aspirin therapy redundant for conventional on-pump CABG. The present study is carried out in patients undergoing off-pump CABG which obviates the need of cardiopulmonary bypass. Several reports documented that procoagulant or event hypercoagulable state would be developed after off-pump CABG probably attributed to much better preserved hemostasis in off-pump CABG compared with conventional on-pump CABG. The systematic review of 50279 patients taking aspirin for secondary prevention reported by Biondi-Zoccai et al indicated that aspirin withdrawal was associated with three-fold higher risk of major adverse cardiac events. It is speculated that, by virtue of platelet inhibition and antiinflammatory action of aspirin, keeping patients on continuing aspirin therapy prior to off-pump CABG may help attenuate the procoagulant or hypercoagulable state during the operative period and may also reduce thrombotic events while awaiting surgery. The issue whether the benefits of preoperative aspirin use may exceed the risk in patients undergoing off-pump CABG is of great importance and of much concern. In the first place, the effect of preoperative aspirin use on offpump CABG has seldom been detailed. In addition, it is a frequently encountered clinical question which needs to be answered urgently due to an increasing volume of Off-pump CABG performed in Asian countries which accounts for at least 60% of all the CABG. In the present study of 1418 patients undergoing off-pump CABG, we found there was no significant difference between the two groups in in-hospital mortality, stroke, intra- and postoperative blood loss, blood transfusion requirements and duration of intubation. Although not statistically significant, the rate for reoperation for bleeding was doubled in aspirin users group. With regard to mid-term endpoints during follow-up, no significant difference was observed among those two groups in Mace-free survival estimates and survival estimates free of rehospitalization for cardiac reasons. The present study also shows that despite of significant angina-free survival benefit associated with preoperative aspirin use in Kaplan-Meier survival analysis, but such difference did not reach significance in Cox proportional hazards regression analysis, with only a trend of preoperative aspirin use to decrease the mid-term hazard of angina recurrence. Due to the inconsistent recommendations from the aforementioned guidelines, the decision of preoperative aspirin use was varied among surgeons in our center. Surgeons were grouped into those who favored or disfavored or had no special requirement for preoperative aspirin use respectively. The surgeon’s decision on preoperative aspirin use was generally for all his patients, rather than for subjectively selected patients. However, under some clinical scenarios, surgeons who advocated discontinuation of preoperative aspirin use would also perform off-pump CABG for patients with continuation of preoperative aspirin use. Generally, those two groups were R428 operated by the same group of surgeons.