Effects of preoperative enoxaparin on bleeding after coronary artery bypass surgery

Abstract

Background: Low molecular weight heparins are replacing unfractionated heparin in practice prior to cardiac surgery. This study examines postoperative (post-op) bleeding indicators in patients who received enoxaparin and underwent elective isolated first time coronary artery bypass graft.

Methods: A total of 125 consecutive patients who underwent this procedure between 2009 and 2011 at one tertiary center were reviewed and divided into three groups: Group A (n = 50) received the last dose of enoxaparin between 12 and 24 hours before surgery, Group B (n = 25) received the last dose before 24 hours and Group C (n = 50) did not receive enoxaparin. Perioperative bleeding indicators and transfusion rates were compared.

Results: Preoperative patients' characteristics were comparable between the three groups. There were no perioperative deaths, return to the operating room for any reason, nor major bleeding. Post-op bleeding indicators were similar in the three groups. The average chest tube drainage at 24 hours post-op was 880 mL, 695 mL and 830 mL in Group A, B and C respectively (p = 0.71). Transfusion rates of red blood cells were not statistically different (Group A 56%, B 64% & C 62%; p = 0.747). In multivariate analysis, female gender, older age, and preoperative clopidogrel intake (stopped 5 days prior to surgery) were associated with higher transfusion rates.

Conclusion: In elective first time coronary artery bypass graft patients who had no aspirin or clopidogrel intake 5 days prior to surgery, the use of enoxaparin up to 12 hours prior to skin incision does not increase the risk of post-op bleeding.