Clinical Pathology Selected Abstracts, 1/15

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Value of TEG in determining cause of bleeding associated with cardiopulmonary bypass

A common complication of cardiac surgery with cardiopulmonary bypass is intraoperative and postoperative bleeding. Therefore, monitoring and identifying the cause of coagulopathy is an essential part of cardiac surgery. The authors conducted a study to compare the bleeding-monitoring method thromboelastography (TEG) with standard coagulation tests, including prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen, and D-dimer, in patients with active bleeding. They performed a retrospective study of patients who underwent cardiac surgery with cardiopulmonary bypass. A second analysis examined if a shortened TEG R time is associated with thrombosis. The authors compared TEG with standard coagulation tests in 21 bleeding patients. Of those patients, 15 had normal TEG values and three had a shortened R time. However, all patients had abnormal standard coagulation tests. Postoperative bleeding was noted in 18 of 67 patients who underwent surgery with cardiopulmonary bypass. The TEG R time and coagulation index, PT, and PTT collected after cardiopulmonary bypass were associated with postoperative bleeding in univariate analysis. However, only PT was independently associated with postoperative bleeding in multivariate analysis. With regard to thrombotic events, three of 38 patients with a normal TEG and four of 43 patients with a shortened R time had a thrombotic event. The authors concluded that the shortened TEG R time may not represent a hypercoagulable state. Although TEG is often used to predict bleeding associated with cardiac surgery, this study showed that TEG parameters were not independently predictive of postoperative bleeding. The authors noted, however, that a limitation of the study is the retrospective design of the data collection.

Welsh KJ, Padilla A, Dasgupta A, et al. Thromboelastography is a suboptimal test for determination of the underlying cause of bleeding associated with cardiopulmonary bypass and may not predict a hypercoagulable state. Am J Clin Pathol. 2014;142:492–497.

Correspondence: Dr. Amer Wahed at md.a.wahed@uth.tmc.edun