[Thromboelastography and classical coagulation tests in the preoperative period of liver transplantation]

Compared to standard coagulation essays (SCE), such as international normalized ratio (INR), prothrombin activated partial thromboplastin time (aPTT), or platelet count, thromboelastograhy (TEG) offers precise and real-time information about hemostasis. TEG tests both platelet function and coagulation by assaying several parameters of clot formation dynamically in whole blood.

To evaluate hemostasis in cirrhotic patients undergoing liver transplantation and determine the positive and negative predictive values of SCE for alterations of TEG.

Preoperative SCE and TEG were prospectively analyzed in 25 patients. Results were categorized as normal, laboratory alteration or clinical alteration. SCE results were compared with TEG parameters to determine positive (PPV) and negative predictive values (NPV).

Hemostasis was abnormal and laboratory abnormalities were observed in all patients. One patient had clinical signs of excessive bleeding. SCE were abnormal in all patients and TEG was normal in nine patients. The most common alteration in TEG was hypocoagulability, in some cases associated with hypercoagulability and hyperfibrinolysis. Two patients had solely hypercoagulability. PPV of INR, aPTT, platelet count and fibrinogenemia were 0, 0, 0.5 and 0.17 respectively. NPV of the same tests were 1, 1, 0.34 and 1 respectively.

Hypocoagulability was the most common laboratory alteration, however, clinical signs of coagulopathy were rarely present. SCE had a poor predictive value to diagnose o discard hemostatic abnormalities.