Does incorporation of thromboelastography improve bleeding prediction following adult cardiac surgery?

Abstract

Cardiopulmonary bypass (CPB) coagulopathy increases utilization of allogenic blood/blood products, which can negatively affect patient outcomes. Thromboelastography (TEG) is a point-of-care measurement of clot formation and fibrinolysis. We investigated whether the addition of TEG parameters to a clinically based bleeding model would improve the predictability of postoperative bleeding. A total of 439 patients’ charts were retrospectively investigated for 8-h chest tube output (CTO) postoperatively. For model 1, the variables recorded were patient age, gender, body surface area, clopidogrel use, CPB time, first post-CPB fibrinogen serum level, first post-CPB platelet count, first post-CPB international normalized ratio, the total amount of intraoperative cell saver blood transfused, and postoperative first ICU hematocrit level. Model 2 had the model 1 variables, TEG angle, and maximum amplitude. The outcome was defined as 0–8-h CTO. The predictor variables were placed into a forward stepwise regression model for continuous outcomes. Analysis of variance with adjusted R2 was used to assess the goodness-of-fit of both predictive models. The predictive accuracy of the model was examined using CTO as a dichotomous variable (75th percentile, 480 ml) and receiver operating characteristic curves for both models. Advanced age, male gender, preoperative clopidogrel use for 5 days or less, greater cell saver blood utilization, and lower postoperative hematocrit levels were associated with increased 8-h CTO (P < 0.05). Adding TEG angle and maximum amplitude to model 1 did not improve CTO predictability. When TEG angle and maximum amplitude were added as predictor factors, the predictability of the bleeding model did not improve.

Relationship of thromboelastography and conventional clotting test values with severe bleeding in critically ill patients with coagulopathy: A prospective study

“…Overall, our results show that only pFB and TEG‐MA were moderately associated with severe bleeding, although their predictive ability was far from optimal. This is in line with the findings of previous publications, which produced heterogeneous results regarding the predictive value of SLTs and viscoelastic tests for bleeding in critically ill patients with coagulopathy. Differences in design, clinical scenarios, and the time of sampling could partially explain these controversial results.…”

“…The authors concluded that TEM could not predict which patients were at risk for major postoperative bleeding . In a retrospective study that included 439 patients undergoing cardiac surgery, the addition of TEG‐angle and MA did not improve the predictive ability of a well‐established previous clinical model based on age, preoperative use of clopidogrel, and other clinical variables to detect an increased postoperative chest tube output at 8 hour (75th percentile, 480 mL). Another similar study also found that TEG was not predictive of postoperative bleeding .…”

“…Differences in design, clinical scenarios, and the time of sampling could partially explain these controversial results. For example, the design of the studies was not homogeneous, and authors performed ROC curve analyses, multivariate analyses, or Cox regression analysis . Additionally, the time at which the TEG assay is performed seems to be important.…”

Global assays of hemostasis

“…These settings include cardiac surgery [67–70], liver transplantations [71], sepsis [72], trauma [73–79], obstetrics [80], psychophysiological stress [81]. These systems have also been utilized to evaluate anticoagulant activity [82, 83] and determine what the critical threshold value is for the initiation of antifibrinolytic therapy in trauma [84].…”

Adult cardiac surgery blood/blood product utilization in the post aprotinin era: an 855 patient, community hospital, retrospective experience

“…Although salvaging will recover RBCs, it also removes platelets and coagulation factors, which can promote bleeding postoperatively [8]. We have associated increased CSB administration with increased postoperative bleeding [9]. Although studies demonstrate an independent association between blood transfusion and mortality, bleeding by itself may be harmful.…”