Heparin anticoagulation in patients undergoing off-pump and on-pump coronary bypass surgery

Abstract

The authors analyzed the coagulation data of patients who underwent on-pump coronary artery bypass graft (CABG) or off-pump coronary artery bypass surgery (OPCAB) in a randomized prospective trial. CABG and OPCAB patients received heparin anticoagulation at 400 U x kg(-1), and 180 U x kg(-1) plus 3000 U every 30 min, respectively. In addition, OPCAB patients received a rectal aspirin, 650 mg, during the procedure. Perioperative coagulation test results (platelet count, fibrinogen, prothrombin time, partial thromboplastin time [PTT], activated clotting time [ACT], and thromboelastography [TEG; Haemoscope] were collected from CABG (n = 99) and OPCAB (n = 98) patients. Residual heparin activity after protamine was measured, using an anti-activated factor X (Xa) assay, in 10 patients from each group. Our study showed that the current anticoagulation regimen in the OPCAB patients achieved a peak ACT of 445 +/- 73 s, and it preserved platelet counts and fibrinogen levels. A residual heparin effect was detected, with residual anti-Xa heparin activity of 0.2 U x ml(-1) up to 2 h after surgery in the OPCAB group. Despite the residual anticoagulation, the OPCAB group had a similar TEG index of native blood, postoperative chest tube drainage, and non-erythrocyte transfusion rate as compared with the CABG group. We have shown that the heparin anticoagulation regimen in OPCAB patients does not lead to an immediate hypercoagulable state. Total doses of heparin and protamine were lower in the OPCAB group compared with the CABG group, and there was a residual heparin effect on TEG and PTT in the early postoperative period in the OPCAB group.