Effects of preoperative enoxaparin versus unfractionated heparin on bleeding indices in patients undergoing coronary artery bypass grafting

Background We examined the effects of preoperative administration of enoxaparin (ENOX), a low-molecular-weight heparin, on bleeding indices and transfusion rates in patients undergoing coronary artery bypass grafting (CABG). Methods Patients undergoing isolated CABG between 1997 and 2002 who received preoperative ENOX or a continuous infusion of unfractionated heparin (UFH) were randomly divided into three groups: continuous UFH, ENOX last administered more than 12 hours before surgery (ENOX > 12), and ENOX administered less than 12 hours before surgery (ENOX < 12). Perioperative hemoglobin values, transfusion rates, and bleeding complications were compared. Results A total of 69, 58, and 34 patients comprised the UFH, ENOX > 12, and ENOX < 12 groups, respectively. Preoperative demographics and hematologic data were similar among the groups. Compared with the UFH group, the ENOX < 12 group had significantly lower postoperative hemoglobin values (9.6 ± 1.3 g/dL versus 10.4 ± 1.2 g/dL, p< 0.05), higher transfusion rates (73.5% versus 50.7%, p< 0.05), and required more total packed red cells per patient (882 ± 809 mL versus 472 ± 626 mL, p< 0.05). A nonsignificant increase was noted in the risk of returning to the operating room for bleeding in patients who had received ENOX compared with patients receiving UFH (6.5% versus 2.9%). Conclusions The preoperative use of ENOX less than 12 hours before CABG is associated with lower postoperative hemoglobin values and higher rates of transfusion than continuous UFH.