Association of Plasma Fibrinogen and Thromboelastography With Blood Loss in Complex Cardiac Surgery

Abstract

Postoperative coagulopathic bleeding is common in cardiac surgery and is associated with increased morbidity and mortality. Ideally, real-time information on in-vivo coagulation should be available. However, up to now it is unclear which perioperative coagulation parameters can be used best to accurately identify patients at increased risk of bleeding. The present study analyzed the associations of perioperative fibrinogen concentrations and whole blood viscoelastic tests with postoperative bleeding in 89 patients undergoing combined cardiac surgery procedures. Postoperative bleeding was recorded until 24 hours after surgery. Regression analyses were performed to establish associations between blood loss and coagulation parameters after cardiopulmonary bypass including a prediction model with known confounding factors for bleeding. Coagulation tests show large changes over the perioperative course with the strongest coagulopathic deviations from baseline after cardiopulmonary bypass. After adjustment for multiple confounders, viscoelastic clot strength instead of fibrinogen concentration showed a similar performance for 24 hour blood loss and a better performance for 6 hour blood loss. This makes intraoperative viscoelastic testing a useful tool to strengthen early clinical decision-making with the potential to reduce perioperative blood transfusions.

Risk Factors for Hypocoagulability After Cardiac Surgery: A Retrospective Study

“…10 In contrast to conventional coagulation tests, which assess only single steps in the entire coagulation process, thromboelastography (TEG) can simultaneously assess the entire coagulation pathway, detecting insufficient levels of coagulation factors, reduced activity of fibrinogen or platelets, and hyperactive fibrinolysis (Figure 1). TEG is now widely used for monitoring coagulation function as well as guiding blood transfusion [11][12][13][14][15][16][17][18] and the use of anticoagulant or antiplatelet therapies. 19,20 Here we used TEG to assess pre-and postoperative coagulation function in patients at our medical center who underwent cardiac surgery involving cardiopulmonary bypass (CPB), and we explored potential associations between risk of hypocoagulability and clinicodemographic or perioperative characteristics in order to identify risk factors.…”

“…10 In contrast to conventional coagulation tests, which assess only single steps in the entire coagulation process, thromboelastography (TEG) can simultaneously assess the entire coagulation pathway, detecting insufficient levels of coagulation factors, reduced activity of fibrinogen or platelets, and hyperactive fibrinolysis (Figure 1). TEG is now widely used for monitoring coagulation function as well as guiding blood transfusion 11–18 and the use of anticoagulant or antiplatelet therapies. 19,20…”