Activation of Coagulation and Fibrinolysis During Cardiothoracic Operations

Background. During open cardiac operations using cardiopulmonary bypass, there is activation of coagulation and fibrinolysis. We assessed the separate contributions of the surgical procedure itself and cardiopulmonary bypass to this, by studying sequential samples from patients undergoing routine open cardiac operations or thoracic operations without cardiopulmonary bypass. Methods. Activation of coagulation and the extent of fibrinolysis were measured from sequential samples obtained before the operation to 48 hours after the operation for 7 thoracic patients and 8 cardiac patients. Results. In the thoracic group operation length was shorter (p = 0.002), and there was no significant increase in thrombin–antithrombin III complexes or image-dimers until 24 hours postoperatively. In contrast, there was a highly significant increase in thrombin–antithrombin III complexes (p = 0.0043) and image-dimer levels (p = 0.009) during cardiopulmonary bypass. The increase in fibrinolytic activity was caused by an increase in tissue plasminogen activator (p = 0.013). At 48 hours postoperatively, the cardiac patients had a more hypercoagulable state than thoracic patients with significantly higher levels of thrombin–antithrombin III complexes (p = 0.041) and plasminogen activator inhibitor-1 activity (p = 0.0033). Conclusions. This study suggests the major activation of coagulation and fibrinolysis seen during cardiac operations is caused by the use of cardiopulmonary bypass.