Effects of coagulation factor deficiency on plasma coagulation kinetics determined via thrombelastography: critical roles of fibrinogen and factors II, VII, X and XII.

BACKGROUND: Thrombelastography (TEG) is used to assess coagulopathy. However, a comprehensive characterization of the effects of specific coagulation factor deficiencies and mode of activation on TEG data does not exist.
METHODS: Thrombelastography was performed for 15 min with control plasma and plasmas deficient (<1% activity) in Factors II, V, VII, VIII, IX, X, XI, XII, or XIII activated with celite (0.28 mg ml(-1)) or tissue factor (TF, 0.1%) (n = 6 per condition). Additional fibrinogen concentration activity (75-345 mg dl(-1)) and Factor II, VII, X and XII activity-response relationships (1%, 6.25%, 12.5%, 25%, 50% and 100% activity) were obtained (n = 8 per condition). Thrombelastography parameters included reaction time (R), angle (alpha), and clot strength (A, amplitude; G, elastic modulus).
RESULTS: Celite activation of FXII-deficient plasma, TF activation of FVII-deficient and FX-deficient plasma, and celite or TF activation of FII-deficient plasma resulted in an almost undetectable clot. Compared to control values, celite activation of plasmas deficient in FXI, FIX and FVIII resulted in prolonged R and decreased alpha values, whereas TF activation resulted in decreased alpha values. Celite and TF activation of FV-deficient plasma resulted in prolonged R and decreased alpha values, whereas FXIII-deficient plasma had decreased alpha, A and G-values compared to control values.
CONCLUSIONS: The fundamental finding of this study is that coagulation factor deficiencies affect TEG parameters in both a factor-dependent and activation-dependent fashion. Utilizing both celite and TF activation improves the diagnostic power of TEG. Based on such TEG data, more targeted administration of blood products could potentially help improve perioperative hemostatic outcomes.