The correlation between conventional coagulation tests and thromboelastography in each phase of liver transplantation

Thromboelastography (TEG) is gaining increasing acceptance in liver transplantation (LT) with conventional coagulation tests (CCTs) such as prothrombin time (PT), activated partial thromboplastin time (aPTT), antithrombin III (ATIII), platelet count (PLT), and fibrinogen concentration. The purpose of this study was to evaluate the clinical utility of TEG in LT and investigate the correlation between TEG and CCT values during each phase of LT.

Medical records of patients who underwent deceased donor LT at a single, university hospital between October 2010 and July 2015 were retrospectively reviewed. Blood samples were obtained at each phase of LT (pre-anhepatic, anhepatic, and neo-hepatic phase) according to our institutional LT protocol and utilized for analysis of TEG and CCTs. The Spearman correlation coefficient between TEG and CCT values were obtained.

During the pre-anhepatic phase, the reaction time (R), PT, and aPTT did not correlate with each other, but demonstrated a negative correlation with PLT. Clot formation time (K) demonstrated a similar correlation with R and a negative correlation with fibrinogen. The maximal amplitude (MA) and α-angle (α) were positively correlated with PLT and fibrinogen and inversely correlated with aPTT. During the anhepatic phase, MA was significantly correlated with PLT and inversely correlated with aPTT; other parameters had weak or indistinct correlation. During the neo-hepatic phase, R and K were significantly correlated with aPTT and inversely correlated with PLT and fibrinogen. A correlation of MA and α with PLT, aPTT, and fibrinogen was also observed. Clot lysis at 30 minutes and estimated percent lysis were inversely correlated with levels of ATIII and fibrinogen.

Conventional coagulation tests and TEG show particularly poor comparability during the anhepatic period of liver transplantation. TEG can be most reliable in the anhepatic phase, during which dynamic hemostatic changes occur.