Aspirin resistance after off-pump coronary artery bypass graft surgery

Abstract

Objective The present study was designed evaluate the aspirin effectiveness in the inhibition of platelet aggregation in patients after OPCAB.Methods 290 patients were recruited.145 patients underwent first time OPCAB (surgery group).Arachidonic acid induced platelet aggregation and urine 11-dehydro thromboxane B2 (11-dehydroTxB2) were measured before operation and on aspirin re-administered days 1,4, 10, and 6 months after surgery.The same tests were also detected in 145 patients from the cardiology department (non-surgery group) received medicine therapy as controls.Results Ninety-nine patients were defined as aspirin sensitive after OPCAB (AS Group).Postoperative aspirin resistance was identified in 46 (32％) patients at the first day after aspirin treatment started (AR Group).19 (13％) and 5 (3％) patients remained as AR at day 4 and 10 after aspirin re-administration, respectively.Patients in the AR group had higher 11-dehydroTxB2 levels than those in the AS group (P = 0.049).Six months follow-up showed ARA-induced platelet aggregation was (11.5 ± 3.4) ％.Urine level of 11-dehydroTxB2 was (50.3 ± 15.4) ng/L.No resistance was found.All cardiologic patients were identified as aspirin sensitive, the change of platelet aggregation and 11-dehydroTxB2 were similar as those in the AS group.Weight ＞75 kg and postoperative drainage ＞500 ml were risk factors of aspirin resistance after OPCAB.Conclusion Anti-platelet effect of aspirin was reduced during the early postoperative period in certain patients undergoing OPCAB.In case of resistance,antiplatelet treatment strategy should be intensified or modified. Key words: Aspirin; Coronary artery bypass graft off-pump; Platelet aggregation; Thromboxane B2